MadModder
The Shop => CNC => Topic started by: ddmckee54 on January 12, 2026, 11:58:15 AM
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I recently purchased a small CNC router, fully intending to heavily modify it and turn it into a more respectable machine. This machine started out life as a Vevor 3018, the previous owner had upgraded it to a 4030 and upgraded the spindle to the high speed spindle motor. As built, these machines are real lightweights, the frame is made of 2020 and 2040 aluminum extrusions. But, Awesome CNC Freak has shown that with some TLC these little guys can be used to do useful work. He's machined a lot of the parts for his DIY 5 axis CNC using his modified 3018.
These are some of the cons that I see and what I plan to do about them:
1) It's a lightweight, it has no mass to it, and no base. I plan on adding a substantial base to this little guy. The first plant I worked in made laminated plastic sheets, I saw them make sheets anywhere from about 20 thou, up to 11 inches thick. In the years that I worked there, I accumulated several of their rejects. I'm going to use a 400mm x 600mm part of one of those 30mm thick sheets to make the base that every thing else will be bolted to. That 400 x 600 x 30 mm piece weighs over 20 pounds, and I can bolt that to the bench if needed.
2) They only used 10mm guide rails, those things will flex like crazy. I'm going to up-size the 10mm unsupported rails, to 12mm fully supported rails. Just going from 10mm to 12mm rails would be an improvement in rigidity, but using the fully supported rails should make that an orders of magnitude improvement. The X axis rails will be bolted to the base, further increasing their rigidity. The new 12mm Y axis rails will also be fully supported, and bolted to new 2040 extrusions - instead of being just a 10mm rail hanging in space. I also plan on bolting those new 2040 extrusions together, which should also help to stiffen up the gantry. If I have to, I can use this guy to mill out new gantry side-plates out of some more of that 30mm stock.
3) The Vevor control board leaves much to be desired, it's being replaced with an ESP32 control board with MUCH better stepper drivers.
4) They used about the cheapest, lowest torque Nema 17 steppers possible. There's no ID on them at all, but they're about the right size to be the 40-ish oz.in version. I already have MKS42 closed loop stepper controllers for these guys, If I need to upsize the steppers, I can go to 84 oz.in or 92 oz.in steppers in Nema 17, and still drive them with the MKS42's.
5) The stock Z axis just plain sucks, it's made out of injection molded plastic and it's only got 40mm of travel. It also has 10mm rails, but they're a LOT shorter that the X or Y axis rails so that alone makes them much stiffer. I can 3D print a temporary replacement that will give me more travel while working on a permanent solution.
6) The spindle, where to start, it's a GS-775M , 20K rpm, 75W motor. But at least it's got an ER-11 collet adapter on it. I can't complain too much I guess, my Unimat's motor is 100W, my Sherline's is about 125W, and my first CNC - back in the late 90's - had a whopping 60W spindle motor. Awesome CNC Freak used a 200W motor with a speed reducer in his 3018, might do something like that. And then there's always that 1KW water cooled spindle and VFD that's been sitting in a box waiting for me to finish its' project.
7) This thing is drip-fed g-code through a G-code sender, I've got a used Tiny PC coming that will do just that. I've accumulated a DDCS stand alone controller and stepper drives over the years, which are also a possibility.
This and my other unfinished projects will keep me busy over the winter.
Don
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Well, one nice thing about them (I don't own one btw) is that they are cheap and accessible. A heavy machine with powerful motors and spindle is out of reach for many. And they make an interesting upgrade project, which sounds like what we're in store for here! :beer:
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"Interesting upgrade project", yes indeedy.
I got the 400 x 600 x 30mm base cut to size, and all the sharp edges taken off. There's a lot stuff that needs to be bolted to the base, I'm thinking drilling & tapping will be best. I'll just use longer screws for more thread engagement in the plastic. It's HARD plastic, but it IS plastic. I knew there was a good reason that I bought that push-pull power tapping attachment.
My 12mm rails arrived a couple days ago. I first ordered the rails about 3 weeks ago, when they showed up I lifted the box I thought "My God, this is an awful heavy box for 12mm rails." Turned out they were 20mm rails, I checked my order and sure enough that's exactly what I ordered. When I contacted the seller about returning the rails, he made a counter offer. He offered a 40% refund and I just keep the rails, saves both of us the hassle of returning them. So now I have a pair of 20mm diameter, fully supported linear rails that are 1m long for some future project - with 2 sets of bearings.
I got the X axis 12mm rails cut to length yesterday. I needed 450mm of rail for an exact fit, I cut them to 430mm so I could move them around a bit if needed. The rails are hardened so I had to use the spinning wheel of death in an angle grinder to deal with them - I don't want to have to cut them more than once. When I started mocking things up I discovered that by some happy coincidence the bottom of the bed is exactly 1/4' above the top of the bearings - talk about dumb luck! And I just happen to have a couple of short chunks of 1/4" x 2" aluminum flat stock laying around. The bed will be in the original location, so no mucking about with the X axis leadscrew. I think I can keep the Y axis leadscrew in the same spot, but when I print the replacement Y axis carriage I'll most likely need to move the lead nut location. The new 2040 extrusions for the Y axis rails should be here in the next day or so, then I'll have a better idea what things could/will look like on the gantry.
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It's picture time. This is the top of the old cnc, or what's left of it.
(https://lh3.googleusercontent.com/pw/AP1GczOShFqXjT0T_L4ltK9QJrIVx16evV4uLFKKZ3VV8rGiEWkVUQwSRvHStftem0Zs2gCVCxw5ReJGpqgB2xOQz8YHpogj-oexEvuIycamGVoqW3HdjhE31oNb384f5_rBcIHV3a2kqW4FumDhyV9cgOgu=w640-h480-s-no?authuser=0)
That's a 12" scale in the upper LH corner for size reference.
Here's the belly of the beast.
(https://lh3.googleusercontent.com/pw/AP1GczNWKolLobYriXGgD_zV4LKh57hd_JYmCc9jNqv8hZS5iKsOefOhMLNfUCyFYZqMNOZIBwFzp31G-YwNlndCZ13d-Ixjy2OoK8BHW4nqcI210D_72RdRxpaRUYkgHcI63d-_wzxGrZAl_1aCvrEhddPP=w640-h480-s-no?authuser=0)
Both the horseshoe shaped top and the base are 1 piece metal castings. I took them apart to make getting this off my workbench a little less clumsy. I'm pretty sure the base is aluminum, but as heavy as the top section is it could be Zamak. Then again, there IS a lot of steel bolted to the top. That orangish blob in the center is the 2 piece carriage for the Bosch 1Hp router. It was machined using the original convoluted belt drive system that could only handle a DOC of about 0.010" at MAYBE a 10"/minute feedrate. I remember it seemed like it took about a thousand passes.
OK, this is the new toy, it's sitting on its' base but nothing is bolted down yet.
(https://lh3.googleusercontent.com/pw/AP1GczPaj41c3uS0BrQT33lYzSWJCCg0gOpMc917WE6wl6I7xXJ2nVgZL5nzshdgdJx3paR20qdfv6VMxfcIHhA_aC7ppk3sV7CYse-xOnFSsqyoS-FG-cBnxViiU8vhdRYcGp6O9JM2gCtKllXf4fOzmqff=w640-h480-s-no?authuser=0)
The Sherline is visible sitting in the corner, that corner is where the old cnc sat for at least 15 years.
This next shot shows dumb luck in action.
(https://lh3.googleusercontent.com/pw/AP1GczNt9D0h_tkWW320QoJ5Eqq5FQjgf8AN7EKZ0M4ABOqbJVSd6WwyNy49afRDaW59oMJ0Gnr1PJJ_6DOWrOSD9t9MLKj7bN0acAyJOr7J5JqDzYgizqPqp1-KodvdiWtjLsMhwpIB0CuWsd7s28aIIqS0=w640-h480-s-no?authuser=0)
In the background you see one of the new X axis 12mm rails with its' bearing blocks, just in front of it is the existing 10mm rail that's 450mm long and only supported by an M5 bolt at each end. The new 12mm rails are bolted to a solid aluminum extrusion that will be bolted to the base by a pair of M5 bolts every 100mm. The rails will be shimmed as required to make sure they stay flat. In the foreground is the 1/4" x 2" aluminum bar that the bearings will be bolted to. As you can see, that bar JUST fits under the work table. Like I said, this is dumb luck in action - not prior planning. Right in front of that is one of the 2040 extrusions that are the major support of the machine, and the just hang off 2 M5 bolts at each end. There's about a 4.5mm gap between the extrusion and the surface. It's no wonder that people complain about the lack of rigidity in these things, there's just so many places built into them where things can flex. I intend to make spacers and bolt through the 2040 extrusion and the spacer into my 30mm base.
This is the spindle, in all its' glory whatever.
(https://lh3.googleusercontent.com/pw/AP1GczPpf-AyXy07DSz2EOcm9il0kwb9aSb8q3rGS6jzmRDoJpOn4M99pjsmJW-zKRi0YpHgv6ZJl7XLACJQJU8h79hLQ4DGYln6jhkdRbZFfu_r5vA5OZSAcvO9JaKemkB_KArL8rBXcjqmypTfrlsLXupO=w640-h480-s-no?authuser=0)
This assembly is 60mm at it's widest, and it uses every mm of the existing rails to get its' 300mm of spindle travel. The problem is that the new bearing blocks are 40mm long, and there's 2 per rail for stability. That's 80mm, and if you figure in a generous clearance Clarence - you're up to 85mm. So any way you slice it, with the existing gantry set-up I'm going to lose 25mm of work area. For now, I can live with a 4027 instead of a 4030. Especially when you consider that my old cnc was a 3020. You can also see that they didn't use any more plastic in those moldings than they absolutely had to, it's not just the rails that flex.
This shows where the new Y axis rails will sit in relation to the existing rails. The camera really messes with things, the old 10mm rails look bigger than the new 12mm rails, but it just ain't so - I checked to be sure.
(https://lh3.googleusercontent.com/pw/AP1GczOuRZuiIcQAeHHmWATuDEuowMq40T_vaHTMIZct2lRkErNkn7uXvJR35gfAcf1hK3Jb1e-7cSn8qRYE6L0Sv4Kl_LgUzhRLYzaq3oTzpREyjPhz6BbOvIDJEm28WonD7FKXtiG-9rWiAjj7DAE8w07_=w640-h480-s-no?authuser=0)
I just got the 2040 extrusions to replace the existing 2020's. If I did the arithmetic right, I should have about a 15-16mm between the new extrusions when they're installed. I intend to make solid spacer blocks to fit between the 2040 extrusions and effectively turn them into a truss. At that point, the weak link in the gantry will probably be the 15mm phenolic side plates. If that's the case, I can try bolting on a stiffening rib, or just making some new side plates out of my 30mm stock.
The major renson I went with an ESP32 based controller is that the MKS DLC32 has the horsepower, and the programming, to function as a stand-alone controller if desired - no drip feed from GRBL required. Just load your g-code onto a thumbdrive, plug that into the controller, and run the file.
That's enough yapping for today, I have to go make myself some supper.
Don
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I got a little more done today, but nothing worthy of any pictures. I finally quit waffling about the Y axis rail length, I needed 370mm so I marked them at 370mm. When I cut the rails, I cut on the"good" side of the line rather than the waste side. The kerf from the spinning wheel of death, and its' clean-up, gave me about 3mm of clearance. The 2040 rail supports I cut at 370mm on the table saw with a carbide blade, I took it slow, wore ear protection, and it worked like a charm - or so I thought. Except... They weren't the right length, and they weren't even the SAME length - despite the fact that the fence setting had never been changed. After doing a root-cause analysis of the problem, it was determined that some NUMBSKULL had forgotten to lock the fence down on the saw. Fortunately they had grown in length rather than shrinking, so they were saveable. I set the fence back to 370mm, locked it down this time, and trimmed the pieces to length. I tapped the ends of the extrusion M5, and replaced the existing 2020 extrusions. I was a little off on my estimate of the gap between the new extrusions, it's actually 16.5mm.
I figured out why this particular 30mm sheet was scrapped, the rail in the foreground in the above pictures rocks back and forth. I can hold one end down and measure about a 0.015" gap under the other end, so there's probably about a 0.008" lump in the middle. Looks like I've got some shimming in my future. The background rail sits flat now, but I'll probably have to shim it to level it to the front rail.
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After doing a root-cause analysis of the problem, it was determined that some NUMBSKULL had forgotten to lock the fence down on the saw.
Sounds like you had the kind of day in the workshop that I always seem to experience.... Glad you saved it though!
I am watching with great interest, as I also have one of those floppy 3018 machines; I've only used it a handful of times so far, mainly because it's so loose, I thought it would make a good CNC PCB drilling machine - which it would, if only the rest of my PCB production skills were worthy of its accuracy...
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Ade, straight out of the box there's so many ways these things can flex and bend that it isn't even funny. And I'm less than impressed with their "lead nuts", they WILL be replaced. I'm not expecting to be able to hog out tool steel with this thing when I'm done, but light cuts in brass/aluminum/plastic it should be able to handle. And if I'm really lucky, even lighter cuts in steel - Awesome CNC Freak has shown it can be done.
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I've been working on figuring out just exactly how I'm going to attach the new pieces to the existing hardware, so I started 3D modeling the relevant bits. The hardest part of that was determining the actual location of the leadscrew in relation to the new linear rails. I could determine the position of the existing rails in relation to the mounting locations for the existing 2020 extrusions and I'm reusing those same mounting holes for my new 2040 extrusions. So I had a fixed starting point. As near as I can tell, the center of the leadscrew is on the vertical centerline of the existing 10mm rails. However, it is not centered BETWEEN those rails. Oh no, couldn't do that, that'd be too easy. The leadscrew's centerline is 1mm BELOW that center - and I am NOT moving that leadscrew.(Yet) After a lot of head scratching, and double-checking/triple-checking/quadruple-checking of measurements, I started modeling the important bits of the Y & Z axis. This is where I'm at now:
(https://lh3.googleusercontent.com/pw/AP1GczNMy5yBp7QJX8iP1cI1UC_0nkLAkg8llHTwLVCias8d36ujISnb_zOpW3Fx63J85xfeLNpiqsgxKAMzvwLdGM2oisSvVucGI4PvZfGb19Kz2aFh039Q3iPwHnnOb4k1AKjFkYwbQH8UpszJTXBuamdW=w640-h334-s-no?authuser=0)
The orange colored bit is the Y axis leadscrew, the cyan bit is the mounting plate for the bearing blocks/lead nut holder/Z axis. I ordered enough anti-backlash lead nuts to replace all of what they used as lead nuts. I don't think any of them were actually bolted to anything, so far they've just been a push fit in the moldings. Before I ordered them though I figured it just MIGHT behoove me to determine what flavor of T8 trapezoidal screw they were. It turns out they are T8 screws with a 2mm pitch, 2 starts, and a 4mm lead, so that's the flavor that I ordered. Things will be a little "tight" where the Y axis lead nut will live - there's 19mm between the bearing blocks, and the lead nut will be occupying 14.5mm of that. I'm going to 3D print the lead nut holder and there's plenty of room above and below the lead screw to put plenty of meat for the lead nut to pull/push on. The Z axis is still just a figment of my imagination, once I can get it out of my head and into the computer I'll share it. I do know that I want to shoot for 75-80mm of Z travel, that'll let me fasten a replaceable spoil board to the bed and still give me a decent work envelope.
Don
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Some progress has been made on embiggening the Z axis carriage and spindle mount, this is where the design is now.
(https://lh3.googleusercontent.com/pw/AP1GczMLN2IxDnlIFXvN8rgiOMBF7A3O_PfxkCn-ZDPnAgQS3gk2GiUY_9KJCvPlS88MdCHz9-Q599945eWlJ3LfZEAYsTNMtTSZDL65hhz2-KgwLaoMK_Yc67r4TPgttkL-sq8ngDtoBBiXPaqSm1ahly2N=w1196-h625-s-no?authuser=0)
The magenta objects are the new Z carriage and the slide for the spindle mount. The carriage length increased from 96mm to 160mm, and the slide height went from 35mm to 48mm. The extra 64mm of carriage length gives me over 75mm of Z axis travel. The extra 13mm of slide height allows me to install two LM8UU linear bearings on each rail, instead of the original one per rail with 11mm of hole leftover to get packed full of shmutz.
Something's not computing in the listed specs on the anti-backlash nuts I bought. I just don't see how you can possibly install M3 bolts in a 16mm bolt circle, when the object you're trying to insert through that circle is 14mm in diameter. The numbers just don't add up. I'm going to have to wait until I have the parts in hand before finalizing the design and doing any printing.
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I got a little more done today, I got spindle mount and clamp designed. I got the anti-backlash nut yesterday, so I was able to get that part of the spindle slide design corrected/finalized. I sectioned the spindle clamp so you could see how I'm bolting the back half of the spindle mount to the slide.
(https://lh3.googleusercontent.com/pw/AP1GczMGZQD2JDxni8eSE6pT46_8iWc_Lfa-lvmVfRwTCJ8azkZpshdbzZJhIV9ih6TimcKayL4_YVawzFRsc-IB_syaKFy_Y3cFXL8Ahr3swfR8_UxXUOCb-lWp4LnNCgkvAnnODbJ-HF8tIB2C7IuqC31t=w1196-h625-s-no?authuser=0)
The mounting holes bolt circle for the nut IS 16mm in diameter, and the major diameter of the part of the nut inside the slide IS 14mm. At least 0.5mm of the 3mm diameter of each M3 screw would protrude into the bore of the spindle slide. There's no way I can use a heat-set insert on these, and I don't trust just threading an M3 screw into plastic - especially when part of those threads don't even exist.
But fear not M'Lords, I have a clever plan. I'm going to change the diameter of the mounting bolt circle to 18mm by slotting the existing holes. Unfortunately I still can't use heat-set inserts though. The only part of the nut inside the slide that's 14mm is the rear flange of the spring-loaded part. And I don't why it's that big, the OD of the spring is 12mm, so you'd think that 13mm would be good enough. Maybe they started with 14mm stock? I'm not going to use M3 machine screws to mount the nut to the slide, I'm going to use long-ish M3 sheet metal screws.
Now I've got a question that I need a little feedback on. Right now I've got the leadscrew nut on the top of the slide, do I need to put it on the bottom? I want the tool forces to be transmitted to the leadscrew by the slide pushing on the flange of the leadscrew nut, not by the slide pulling on the M3 mounting screws.
Don
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QQ - I've often wondered about a linear rail/bearing upgrade to my CNC3018 (although, quite honestly, probably the only thing that would stay original is the motherboard, and maybe the steppers); the rails I was looking at are rectangular in section (e.g. the MGN12 range), whereas you've used the circular version (SBR12?). Was there any particular reason you went with the round rail, vs. the flat rail?
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Ade - there were a couple of reasons that I went with the SBR12 rails over rectangular rails. First, they were cheaper. Second, I've got some history with circular rails. 40 years ago I was working maintenance in a plant that made laminated plastic sheets. There were several saws in the plant used to trim off the rough edges and cut the sheets. The plant ran 24/7 at least 5 days a week, sometimes 7 days a week. I remember that at least 2 of the saws ran on fully supported circular rails, the rest ran on cam follower rollers. In the 3-1/2 years that I worked there I remember changing many cam followers, I don't remember doing anything to the linear rail bearing blocks other than greasing them. I'm not saying that SBR12's are better, just that I trust those rails.
One thing that I just figured out today is that I don't need to bolt the X axis rails to the base, then square and level everything else up to them. The side frames of the CNC are 2040 extrusions, so I can bolt the rails to the side frames and save much tearing of hair and gnashing of teeth. I'm going to use the "Easy" button. I also discovered that the M5 x 10 SHCS that I ordered were JUST long enough that they bottomed out in the slot of the extrusion before the rail was completely tight. I was not looking forward to having to trim that many M5 x 10 SHCS - no matter how I would have done it. Then I remembered that I had ordered a bunch of M5 washers, 0.5mm thick, for my RT7R project - and hadn't used them yet. "Easy" button time again, but I will have to order more - soon.
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Thanks Don! Good to know... a while back, I bought a handful of SBR20 rails & matching bearings - I was planning on building a massive circular saw to cut "billets" of machinable wax square & true - they come out of the mould all kinds of shapes, so the plan was essentially to build a table saw, with the table able to move in the X & Y axes on linear bearings, plus a mechanism to rotate it 90 degrees at a time; so the procedure would be to lock the weird shaped billet down as best as possible, then cut one side, rotate, cut the next side, rotate etc. until square (or rectangular); then set it up vertically and do the top & bottom in the same manner.
Like all big ideas.... nothing ever came of it, but I still have the rails & bearings, just waiting for a project...
I suspect they'd be a tad oversized for converting a CNC3018!
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I suspect they'd be a tad oversized for converting a CNC3018!
Funny thing about 20mm rails... When the 1m-ish box arrived, my impression when picking it up was that it was AWFUL heavy for a pair of 12mm rails. Upon opening the box I discovered I was right, I didn't have 12mm rails, I had 20mm rails. I checked my order and I had ordered the 20mm rails by mistake. I contacted the seller about returning the rails, and he offered a 40% refund if I'd just keep the rails - saving us both the hassle of the return. So now I also have a set of 20mm rails and 4 bearing blocks, just waiting for a project.
The saws I was talking about on the 22nd, the ones that used the cam follower rollers, were like radial arm saws on steroids. They had a 10-15 Hp saw motor, and a chain driven power feed for the saw. The beds of those saws were covered in a grid of ball transfer units. They worked great on the hard slick plastic, probably wouldn't work so good on machinable wax.
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Well, ain't that just a kick in the teeth.
All the various bits and pieces have arrived, sooo... I started assembling the Y rails, and guess what? They DON'T fit! I pre-assembled the tee-nuts onto the rails. Since that would be easier than trying to pre-position the nuts in the extrusions - they would probably move around in the slots. But I could not get the rails to slide into the slots. The tee-nuts fit in the slot just fine, so i started looking for other causes. When in the extrusions the tee-nuts were close enough to being on 20mm centers for using a digital-guesstimator. The holes in the rails on the other hand were on 21mm centers, I know these were cheap rails, but still... Where was quality control, aren't they supposed to check that kind of stuff? Guess these rails must have been made on a Friday afternoon, or a Monday morning. I've got a 5mm end mill, I'll probably set up a jig and just move all the holes, on all the rails, in one set-up.
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I keep telling myself, the best laid plans of mice and men..... but it doesn't really help in these situations. :bang:
I sometimes drill more slots than holes in a day. You don't want to get to the point where you're afraid to drill or cut at all, though, just because of the possibility of screwing something up. And besides, some of the most entertaining threads are where people rehabilitate something scrapped that has problems built into them. Reading about the fixes always creates a good feeling for me.
Anyway, onward and upward with this machine. I'm sure it is already better than the stock version! :coffee: :coffee: :beer:
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I did set up the jig, it's sketchy at best - but it did work.
(https://lh3.googleusercontent.com/pw/AP1GczOwSaIcFlEy2_3gIS6KA3fTibE6AokEtyjEqgOC-X8kTiqsDm2vvIQfNpOHdaJNDnyGO3F1Tdtm9HkcHDG4ZWmYvr8c5ttuoQe9CeO0H7P-XJ52-TP7_JTg4S0uFS70y3F2PC5xuM6TN2p9Yh7bK_l5=w640-h480-s-no-gm?authuser=0)
Yeah it looks sketchy, yes it's made out of scraps, yup that's a 5mm end mill chucked in a drill press, and if you looked at it wrong bad things would probably happen. But it didn't need to survive for long, it just needed to be able to take a crescent shaped slice, about 0.75mm at its' widest, through 4mm of aluminum - 32 times. And it passed that test with flying colors, here's a completed rail still in the jig.
(https://lh3.googleusercontent.com/pw/AP1GczNs_1LXvmvDMTkPhdi5eT78dTFAYvohXA6sCVP2uUAL72MS98_9Ls9Ysyz1-LzGFrJqnLIybYKMFGUHtjaZAcUgI1Cdb8MfyPQOjCGxWwM-ukOMY6vS1qpjMSDp3bkmIm5vgjCWJFaPFx3kLinJqzPf=w640-h480-s-no-gm?authuser=0)
You don't get many chips taking that small of a bite.
I then started putting things together and ran into more problems. Since I'm using 2040 extrusions instead of the original 2020's, I needed to drill holes for 4 more M5 bolts - that hadn't happened yet. I don't know how much I'm paying the guy that drilled the holes, but it's TOO much. The exit point for one of the holes had about a 2mm offset from the entry, a LOT of file work later and that was corrected. You remember when I said that the M3 mounting bolts for the Y axis stepper would JUST clear the new 2040 extrusions? Well they do, they DON'T however clear the rail flanges. Take the rails/extrusions out, clip the corners off the flanges, and reinstall the rails/extrusions. Now, how much clearance do I have between the bearing blocks? WHERE'S THE FLIPPIN' BEARING BLOCKS? Take the rails/extrusions out, install the bearing blocks, and reinstall the rails/extrusions. NOW how much clearance do we have Clarence? About a mm, OK, a miss is as good as a mile. WADAMINUT, where's the grease ports? I'd installed the blocks so that the grease ports were pointing toward each other instead of away from each other. Take the rails/extrusions out, flip the bearing blocks around, and reinstall the rails/extrusions - for about the leventy-leventh time.
OK, now it was time to get serious and start getting this thing squared up. I made sure that both of the 2040 extrusions were in plane and perpendicular to the main side frame extrusions. I made sure that both the side plates were the same distance from the ends of the main frame rails, so the Y axis had a good chance of being perpendicular to the X axis. Then I went around and tightened the bolts, one last time. Annnddd...
Ya know that feeling, when the wrench suddenly loses all resistance and just spins round-n-round-n-round? Yup, I stripped the threads, and I THOUGHT I was being careful. And that's where I left it today.
I know that I ran the M5 threads at least 20-25mm deep in the ends of the extrusions, and I know that after going through the 15mm side frames the M5x20 bolts only had about 4-4.5mm of thread engagement in the extrusions. So there SHOULD be 10-15mm of good threads in the extrusion yet. My current plan is to get M5x30 bolts, that extra length of thread engagement should take care of the problem. (As long as I'm REALLY careful this time.)
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I'm sure it is already better than the stock version!
I don't know about better, but it's got to be stiffer. I found a deal on 84oz-in NEMA 17 steppers, so I'm going to upgrade to them in the near future. By the time all the shouting is over with, there's not going to be many "original" parts left on this thing. Which is probably a good thing.
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Still waiting on the M5x30 bolts, so I've been working of how to fit the mounting bolts for the Y axis leadnut into the available space - 19mm max. M3 bolts on a 16mm bolt circle doesn't leave a whole lot of room to spare - like absolutely none. That being said, the 3D printed leadnut block was deleted from the design. In the process of doing that I discovered that I had never anchored the Y leadscrew into position, because I was never sure where it would actually be located relative to the new rails. That led to much head-scratching as to how I could do that with the tools that I had - an 8" digital guesstimator. (Even though it's a good one.) After much careful measuring, tweaking of the 3D model, more measuring, and more tweaking, I finally got the real world and the 3D model to agree with each other - AND anchored the Y Axis leadscrew in position.
The Z axis quickly showed me that there was NO way I could directly mount the leadnut to the Z axis leadnut to the bearing carrier. Eventually I settled on mounting the leadnut to a 1/8" plate and mount that plate to the bearing carrier/slide. 1/8x1-1/2 HRS flat stock is fairly easy to get, so that's what I'll use as a starting point. I had originally hoped that I would be able to design one leadnut mounting plate and use it for all 3 axis, the Y axis quickly educated me in the folly of my ways. The spacing between the Y axis rails is fixed, as are the position of the Y axis leadscrew, and the positions of the Y axis bearing blocks. The Z axis leadnut plate would NOT work - not even with modifications. So I basically started over, the only things I kept from the Z axis mounting plate were the tapped M3 mounting bolt holes, the clearance hole for the anti-backlash spring, and a maximum width of 36mm - so I could still use 1/8x1-1/2 HRS flat stock. I found that I needed to knock the corners off the mounting plate to clear the X axis rails/extrusions, but that's no big deal. I'm still scratching my head about the bolt locations for mounting the leadnut plate to the X axis bearing blocks, there's some fairly important stuff that I need the holes to miss. When I get the bolt locations nailed down I'll try to remember to get a screenshot so you know what I'm talking about.
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It's taken longer than I'd hoped, but I think I've got a solution to my leadnut problem. I'd purchased 3 anti-backlash leadnuts that were designed for 3D printers. I got to playing around with one of them and realized that the way they worked wasn't going to cut the mustard for this application. They are basically 2 leadnuts installed back to back with a spring between them. The 2 halves are clocked together by a tab and slot arrangement. Only one of the leadnuts is fixed, the other just floats on the leadscrew. Even with all the compression I could get out of the spring, it would still allow the leadnut to move on the leadscrew. The only pre-load you.ve got on the leadscrew is that spring, and it ain't enough. This is what I'm going to try.
(https://lh3.googleusercontent.com/pw/AP1GczMIBZMBcSIcKw37C6vnrsQWBj98PPNpah1ZV-S3PJcp8amYGdN7S89ssHxLjYjZsWWKEXSifnu1FbyGLjM9QXsngD7jjLcxG6RlGiwK6zIRJLUQv6N0iqeygrIG4WCqe-h-jw80VJdYXiNRXHYaGW16=w640-h333-s-no-gm?authuser=0)
It's still just 2 leadnuts back to back, but now I can adjust the amount of pre-load on the screw. This is actually parts from the anti-backlash nut along with a different style of leadnut. The part on the right, with the slots in it, is from the anti-backlash nut. It has a 22mm OD flange with 4 mounting holes. The part on the left is also 22mm in diameter, but only has 2 mounting holes. The sides have been milled off, leaving a 10.5mm wide flange. I'm not showing the original spring, which I will also reuse. I cobbled together a test rig for this set-up and it seems to work. I can tighten things down to the point where I can lock up the leadscrew. I got some Belleville washers, and the current plan is to stack them with a flat washer between each pair so they can't just slip together - losing the leadscrew pre-load. The stack-up shown is a Belleville-Flat-Belleville stack. It's going to take some playing around with things to find the sweet-spot, where's there's minimal backlash and no lost steps. I also realized that the leadnuts will need to be assembled after mounting to the leadnut plate. The leadnut plates will be 1/8" HRS, tapped for M3, that should give me 5-6 complete threads in each hole.
This is what the 3D model looks like now.
(https://lh3.googleusercontent.com/pw/AP1GczMz4MNckBxChw0ngF__yDOqQNrK1tT-HP2IfndPP2sKlEN08RHoEtI0yyI0KuX-MQ3ymhPGhgpP3LDH1zaac-EkbD4k0crkZWDYvJMJwreUZmA0q-vTIV-aF6hGpwHjoWv8L1sCHjm_UO_CzXlFlZ0g=w640-h335-s-no-gm?authuser=0)
The orange bit is the Y axis leadscrew, which I realized a couple hours ago just ain't right. The large lump on the left end should be on the right. That's not that big of a deal, but it will break the constraints in this assembly when I fix it. The yellow parts are the leadnut assemblies for the Y and Z axis. The dark blue parts are the Y and Z leadnut plates. The cyan part is the mounting plate for both the Y axis linear bearings and the Z carriage assembly. I don't show it, but all the linear bearing mounting holes will be countersunk.
Screw it, I'm calling it a day.
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I've been picking away at this thing all week, and it's starting to drive me up the wall. I flipped the Y lead-screw around, and it didn't break as much as I thought it would. But, I have a small issue with Alibre that's REALLY irritating. This is the latest assembly drawing of my new CNC's 3D model.
(https://lh3.googleusercontent.com/pw/AP1GczNbrp5xX_dRazeqitMvpx38u9iDP3WOG8oj0rHdj33T8j0CXe2wCRg9rPFe6LG9SbwrtE5AbMzfN6Q6pZq1WmhB1OiMyHf-Sg0aGJalcILaKHSala0mPSMVxGRnRgFfJ8N6INBSlqvbmuUTQQ9crTbp=w640-h334-s-no?authuser=0)
You see that yellow object in the middle? That's not where it's supposed to be! The lower surface of the flange should be coincident to the upper surface of the dark blue lead-nut plate. The Z carriage, basically everything in front of the cyan colored plate, is one sub-assembly. In THAT sub-assembly, everything behaves like it should, including the lead-nut. However, when the Z carriage assembly is added to the main assembly, the Z axis lead-nut turns into the misbehaving red-headed step-child that you see above,
I thought this problem felt kinda familiar. About a year ago I was working on designs for 1/16 scale RC truck differentials, based on a modified cheap Chinesium 1/10 scale RC car differential. I started out wanting just the front and rear axles for a tandem dual drive set-up. Later, after seeing how a fellow builder had modified the front axles from a similar 1/10 scale RC crawler into powered steer axles for his 1/14 scale RC telehandler, my designs morphed into adding a powered steer axle for a 6x6 Bruder truck conversion. I had designed a powered steer axle, and tested it as an assembly, where the steering worked fine. When I added that sub-assembly to the main truck, it would no longer steer. The same thing happened with the rear axles assembly. As seperate sub-assembly it would articulate, when added to the main assembly it would not. I had a buildlog detailing the designs of the differentials.
I checked back through that Frankendiff build log and found I had run into a similar road-block there. I have a perpetual off-line license for Alibre Design Pro V.22, I am NOT going to pay any more to upgrade it - and maybe not have it work any better. I've checked, seems like sometimes it works, sometimes it don't. AND, then I would have to upgrade to a version of WINDOZE that I like even less than the WIN7 Pro I've got now.
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Before I completely tear this thing apart again here's a couple shots of what it looks like with the new rails installed.
(https://lh3.googleusercontent.com/pw/AP1GczMCN6KZMo1y4uXlNlAf4HqQQm7dxGoe9W4xnbReiIXulnuE2noIGhk4L87YAPtNp63-p6kNUpLiP-RNatV6aB7pTc1rkOfOM_mQeRYO4XfBAAmtJFW4Y0i6BvtxY0szK4_jvnx7a0B5h1Ifxzug0Lgs=w640-h480-s-no?authuser=0)
I installed the mocked-up lead-nut assembly just as a sanity check - it fits so I guess I'm still sane.
Installing the X axis rails on the side frames is causing some issues.
(https://lh3.googleusercontent.com/pw/AP1GczO4szlE7SxZwJeNXkm4-AFZ6E2OC0_RfmQr-UwcEZyj2xpY92u61uxwzUORUdKN4xYKxkjP2q-TyE0vKvLOHe3G0m7b7krWVlFBssqGTcqykw-YkwN00HtKO1QT4TO0opP6ODv7_cFePTM8--ThfNww=w640-h480-s-no?authuser=0)
That change, while it made the alignment of the machine MUCH easier also threw a monkey wrench into some of the other stuff. There is no longer 1/4" between the bottom of the bed and the bearing blocks, it's more like 3-ish mm. I've got some 1/4"x1-1/2" aluminum angle that I will modify to make the bed/bearing mounting brackets. I'll lose another 3mm of Z work height, bringing the max working Z height down to about 60mm, but that will be fixed after I get this thing running again. It can make itself new extended Z height side plates. The X axis lead-nut mounting block will need to change. The current plan is to add 3mm to the dimensions of the existing mount, and print that. Then I install that lead-nut, measure how thick of a shim I need between the lead-nut and the bottom of the bed, print the shim, and install it - Eazzee-Peasee.
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I think your leadscrew idea is interesting, looking forward to seeing if it works out for what you want to do with the machine. Sorry to hear about the Alibre glitches. Frustrating. But it does seem like you're moving along with this rebuild/upgrade. Keep on truckin!
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I managed to get a few things crossed off the ToDo list, AND I've figured out who the culprit is for the lead-nut assembly misbehaving. It's the Nut-Bolt-Washer assembly, and in particular it's the wave washers. When I try to constrain the surface of the wave washer to the face of the bolt, I got NO options for the constraint. Sooo... What I originally did was to anchor every thing in place. I have no idea why it worked in the Z carriage assembly and not in the main assembly. I deleted the wave washers from the NBW assembly, constrained the flat washer to where the surface of the wave washer would normally be, and the little toad started behaving properly. Onwards and upwards I guess.
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Got a little more accomplished yesterday, I've added the base and the main frame to the CNC assembly and determined the "safe" locations in the X & Y 2040 extrusions, places where I can poke the holes that will let me start bolting this thing down. The holes through the X 2040 extrusions will let me bolt the main frame down to the base. The holes through the Y 2040 extrusions will let me bolt the 2 Y extrusions together into a sort of truss. That should really help to stiffen up the gantry. I determined that 50mm from the ends of all the 2040 extrusions was a safe location, far enough away from the end that it wouldn't affect any of the threaded holes in the end of the extrusions. (I just keep forgetting to export the main assembly as a JPEG file before I to post - on different computers dontchaknow.)
That let me determine the locations of the 6 through holes, and the 4 counter-bores that are 10mm deep in the base. I initially was going to tap the holes in the base, I've talked myself out of that. I'm going to give myself a little wiggle room, I plan on using four 1/4"-20 bolts in 5/16" holes to bolt the main frame to the base. The bottom spacers that will support the X 2040 extrusions will be 6mm thick. This will give me 1mm of clearance between the "feet" of the endplates and the base - to try and eliminate any twist that could be caused by the high spot I know exists in the base. I designed 3mm thick spacers for the tops of the extrusions to give the bolt heads and washers a flat spot to live. Totaling up the extrusion, spacers, washers, base thickness, and then subtracting the 10mm counter-bore depth I'll need about 71mm, a 1/4-20x3" bolt should work.
For the 16.5mm spacers that I'll need to bolt between the Y 2040 extrusions, I'll probably use something similar to the bottom spacers for the X 2040's. it'll just have an alignment tab on the top and bottom. That could make printing this part interesting, we'll see how the P1S handles it. I may try print this on an angle for strength, like Clough42 suggested in one of his videos. So far with what little I've printed the results have been outstanding. And I am far from being comfortable with either the printer or Orca - just because they're still so new to me.
I also used Alibre to print a 2D drawing of the base, so I'd be able to lay out the holes that need to be drilled in the base. It took me a while to figure out where, and how, to dimension the model so that I'd get a usable 2D drawing. It took me almost as long to find where to change the drawing units from inches to mm. I plan on laying out the hole locations on masking tape first, as a sanity check, before committing to actually drilling the holes. I also plan to test the counter-bore depth on some scrap to see if I'll need to go deeper than 10mm to be able to use a 3" long bolt. A max of 4mm of threads might get a little dicey, bolt threads might not get to the nylon lock. I've still got 20mm of thickness left in the base after the counter-bore, so I can always go a little deeper.
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This time I remembered to export the new CNC assembly as a JPG file.
(https://lh3.googleusercontent.com/pw/AP1GczMoy32pixdnjkFNVeFaNqGSu5PhkXqMi0lEELRJX87MBO42d6XtguCCn-N9fdcGEj_MHLdaHj57JPwjDYdcsoPvm-ctAIvy90KXMDJT7j43j81wEQ6edFHdbGJXS7DoSnmFx1zYXGHG0l7XWsaPhfUS=w640-h336-s-no?authuser=0)
The magenta colored bits are the parts that will be 3D printed. I added all the spacers to the 3D model that will be used to bolt the main frame to the base, and the spacers that will turn the two Y extrusions into a sort of truss. Coincidently, all those spacers also got printed today, and the center-points for the holes in the base got laid out. I've got to get the holes drilled in the X and Y rails so I can verify that the locations are correct before I drill the base.
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Well... It's one step forward and two steps back time again. I got the machine mostly disassembled, the Y rail extrusions have been removed, marked, drilled, and bolted back together into a single truss. (Had to run out and get some longer bolts, the bolts I had were too short, or too long.) I also added the grease zerks to the Y axis linear bearings, two straight zerks on the two top bearing blocks, and two 90 degree zerks on the bottom blocks to make greasing them easier.
I had taken one of the X axis rails off and as long as I has the kit of zerks fittings out I figured that I'd add the zerks to those bearing blocks as well. All of the set screws in the Y axis bearing blocks were black oxide, the set screws in the X axis blocks were SS. I didn't pay too much attention to that at the time. Not, until I discovered that the Allen wrench that fit the black oxide screws would not fit the SS screws - too big. That's when I discovered that the black oxide screws were M6 - which I knew, but the SS screws were M5. I ain't got no stinkin' M5 grease zerks, M6, M8, M10, 1/8" BSP, and 1/4" BSP I've got - but no M5's. They are now on order. The X rail that is out has been marked and drilled, tomorrow I'll remove the other rail and get it marked and drilled too. I center punched the mounting hole location that was closest to the edge of the base, when I used a transfer punch to mark the other mounting hole in that rail it was about 10mm off from my layout. I remember that when I added the mounting holes to the base, one of the mounting holes at the RH end of the machine was 10mm off - so I corrected it on the base. I then made the 2D drawing of the base that I used to lay out the mounting hole locations on the base. I think I moved the wrong hole in the model, so that's why the RH mounting hole locations were wrong. Good thing I decided to do a sanity check before drilling the holes in the base.
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Picture time...
(https://lh3.googleusercontent.com/pw/AP1GczPv1x7EnRaY2cTiBT_0T8vaA1ja2FXFFHWEGMO4yrbVsuzKxPV4ATMofLxAIT5QjqqYWrq2T09m3C1r1Bqo8DYQ-RuJFaCrq6Zg-XrOz3lHjNzFD2_5zGyx29BOtKuuJ-GozJtRNLbWp0ELhCTcgf1F=w469-h625-s-no?authuser=0)
This is what things look like now, doesn't look a whole lot different than this one does it?
(https://lh3.googleusercontent.com/pw/AP1GczMCN6KZMo1y4uXlNlAf4HqQQm7dxGoe9W4xnbReiIXulnuE2noIGhk4L87YAPtNp63-p6kNUpLiP-RNatV6aB7pTc1rkOfOM_mQeRYO4XfBAAmtJFW4Y0i6BvtxY0szK4_jvnx7a0B5h1Ifxzug0Lgs=w640-h480-s-no?authuser=0)
If you answered no to that question you'd be absolutely right. But there is one MAJOR difference, the frame is now bolted to the base and living in its' new, and permanent, home.
Next step? Get the bed mounting brackets designed/fabricated, and get the bed mounted to the X axis bearing blocks. If you look closely at the base below the second mounting bolt for the X axis linear rail on the far side you'll see the access hole for greasing the X axis bearing blocks. (There's a similar access hole on the near side that's hidden in the view.) Once the bed is mounted I can get to work on the X axis lead-nut mount. I really need to find mt ToDo list and get it updated, this should check off at least a couple more items.
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Is the base from a table leaf? Just guessing!
I'm kinda interested in the MKS DLC32 that you mentioned earlier. I'm pretty unaware of the current CNC circuitboard stuff going on in the maker world other than a failed attempt I made at implementing a working GRBL Arduino system for my older CNC router/mill.
Luckily in that case I was able to get an old laptop working with LinuxCNC again which does work fine with the mill via ancient parallel cable drive. So I dropped GRBL. But I am always curious about what's going on in low cost CNC driver options in case I want to make a custom specialized tool some day, neither lathe nor mill.
I think I understand how that one is programmed, separately from the mill, and then the program is loaded and run either by thumbdrive or wifi etc. I do have a tiny extremely low end 3D printer that accepts a thumbdrive program and then runs it, so I get the concept.
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vtsteam:
The base is a 470x550x30mm piece of laminated phenolic plastic, with a kraft paper core and what, if I'm remembering correctly, were known as canary covers. On my bathroom scales that chunk weighs in at about 25 lbs. In the mid to late 70's I was working in a plant that produced them, in the maintenance department. Every once in a while a sheet would get rejected, this one has about a 0.010-0.015" high spot about 200mm from the LH side, I suspect that was one the reasons for it's rejection. I'd keep my eyes open for any rejects that I thought might be usable in the future. Since they were bound for the landfill anyway, I'd get permission from the production supervisor to take them.
The only ones I wouldn't take were the epoxy/fiberglass sheets, those you can't cut with carbide blades. You have to use a diamond saw on them and basically grind through them. At that time, carbide saw blades for home use were EXPENSIVE, a diamond blade was the stuff of dreams. We had one guy in maintenance whose sole job was to sharpen and repair the carbide saw blades.
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Wow, that's a pretty impressive piece of phenolic! I remember it used to be used in low cost PC boards, but not in 30mm thickness! What were those boards used for?
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My guess would be that it was probably used as an insulator, the stuff machines fairly easily. I poked the access holes and the counter-bores for the mounting bolts using nothing more complicated than a Forstner bit in the drill press.
The thickest slab I ever saw them press was 11" with a canvas core. At that thickness things can get a little dicey, so they are very careful about how they do it. I also saw them try pressing a slab about 8" thick only to have it spit out the side and bind up the press. The press itself was a big hydraulic cylinder in a pit, we wound up changing the seals after this incident and I'm thinking the ram was 36-42" in diameter. The 4 studs connecting the cylinder to the top-hat were 8-10" across. The only thing that dropped the press ram and the heating platens was gravity. When the laminate shifted it became wedge shaped, that cocked the ram in the seals - so it wouldn't drop. They attacked that slab with hand chisels, air chisels, sawzalls, I think they even used a chainsaw on it. That particular type of laminate was designed to laugh at most shock loads - it's used for gears that need to stand up to repeated high shock loads. They finally got enough clearance between the slab and the studs to wrap a cable around the slab. Then some brave soul lunatic volunteered to hook a fork lift to the cable and yank the slab out of the press. (I knew him, lunatic fits.) From the tire marks we had to clean off the floor, it did not give up easily. Between getting the slab out of the press, and waiting for the new seals, that press was down for the better part of a month.
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Presumably this is Tufnol, usually paper or cloth with phenolic resin. I used them for high voltage insulators and mounting plates for electrical assemblies. Also used for gears. Easy to machine but has a characteristic slightly acrid smell..
I have some 12mm sheet (plate?) and 50mm rod in the workshop somewhere....
https://tufnol.com/materials-and-products/ (https://tufnol.com/materials-and-products/)
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Wow, exciting stuff re. that press incident! :coffee:
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Tufnol would be similar, but appears to be a UK product. Almost 50 years ago I worked at https://www.norplex-micarta.com/ (https://www.norplex-micarta.com/) in Postville. At that time the parent company was in Lacrosse, WI, and Postville was definitely NOT the headquarters - let alone global headquarters. Some of the stuff in the video on the website looks VERY familiar. At the time I worked there thermoset sheets were the only product, but there were many flavors of those. May have to do a Google Earth and see what the plant looks like now.
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I got the brackets cut to length and the inside corner radius removed. I found out that my method for bolting the frame to the base may NOT have been such a great idea. Not modeling the bed initially was not a wise move, it gave me the false notion that I had plenty of room to play with. I forgot that the bed overhangs the main frame. Those mounting bolts mean I either need to raise the bed 6-8mm to clear them, or I need to swap those bolts with something else, neither of which I planned on doing. Raising the bed would probably be the simplest, but that means my 65mm clearance over the bed drops down to more like 55mm - at least for now anyway.
Or.... Maybe I just notch the ends of the bed extrusion, that might be the simplest/easiest thing to do. I'll have to check that out, we're probably talking about removing a 10x10mm notch from the bottom of both ends of the bed extrusion. I'm not sure, but I think that extrusion is at least 15mm thick, might be 20mm or more. And how often do you need to put a tee-nut in the last 10mm of the slot? I REALLY need to get the bed modelled, so I can see it before I do any slicing and dicing.
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This stuff?
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Bill, that's the stuff. But I had a reason that I didn't need to model the bed - explained below.
Is there a Meathead of the Month award? If there is, then I'm nominating myself!
I was down in the shop taking enough measurements to allow me to model the bed. I found that I've got 5.28mm between the bottom of the bed and the top of the frame. OK, now how far does the head of the mounting bolt protrude above the bottom of the bed? I measured the top of the bolt at 11.62mm down from the top of the bed. A little head-scratching later and I determined that a 5mm deep notch would give me almost 2mm of clearance. Hokay-fine, now how wide does the notch need to be? Better make sure the bed is centered first. Why is there such a LARGE gap on the far side of the bed, how wide is the bed anyway? Survey says: Bed width - 300mm, space between frame rails - 400mm. (Insert head smacking Homer Simpson DOH moment here.) Wade-a-minut-here, why is there only about 10mm of the bed sitting on the mounting bracket? (Insert another Homer Simpson moment here!) Some dip-stick forgot that the horizontal leg of the bracket needed to point to the center, not the outside, of the machine.
I still need to trim a few mm off the vertical leg of the bracket. But, I can actually gain a couple mm of usable Z height out of this - instead of losing height as I originally feared.
I didn't model the bed because it CAN'T interfere with anything. Despite my original panic, this turned out to be tempest in a tea pot, a much ado about nothing, a Rosanna Rosannadanna "Nevermind" moment.
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I?m afraid the ? Meathead Award ? died with Archie Bunker.
https://youtube.com/shorts/h8o-61uvYbw?si=afbKmCy9Org_1DXl
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Ah, the Sock'n a Sock and a Shoe'n a Shoe bit, I think about it every time I put on a Sock'n a Shoe and a Sock'n a Shoe.
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It's been decent outside. so I've been spending a little time picking up sticks and leaves. But I have made a little progress and crossed 1 or 2 more items off the ToDo list, I've got the bed/bearing mounts bolted to the bearings. I wound up cutting about 4mm off the vertical leg of the aluminum angle.
(https://lh3.googleusercontent.com/pw/AP1GczMI3H-gG2RJw7rteXBOSD-T51lfRn_yWA7FI30Xe76UME5Qq3sp8c_WZdMwuK7qWxjxY3_oxvlVvr6O5yvi1ZP_7LUHn_apJrPfH_ZduNc_LtDrl9Dri7kamatzbghRbkyVOsDUs9FbtGhN9NbKVrqt=w426-h568-s-no?authuser=0)
I'm still not sure just exactly how I'm going to bolt the bed to the brackets yet. If I use an M5 SHCS, that will block off those slots for use by the clamps. An M5 FH would work, but my counter-sink bits are either too big for the slot, or too small for the screw head. I may have to resort to using a drill bit for a counter-sink bit.
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A kind soul on another forum gave me some possible ways to mount the bed to the brackets, including a couple of links. It definitely pointed me in the right direction.
That led me to a trail of bread crumbs, which told me that I needed to measure the slot width - it's 8mm. Searching for an 8mm t-slot nut with an M5 thread led me to the fact that 8mm is the width of the slot on a 3030 extrusion. Searching for 3030 T-slot nuts led me to this, https://www.ebay.com/itm/157340497226 (https://www.ebay.com/itm/157340497226). Which allowed me to verify that these T-nuts had mostly the same dimensions as the ones that came with the clamps, the T-nuts in the link are M5 - the ones from the clamps are M6. (I've got enough issues with M5 screws, M6 would be worse.) One "Buy it now" transaction later and VIOLA, I have a plethora of T-nuts on the way. Although mounting the bed to the brackets, and the X-axis lead-nut to the bed, will take a healthy bite out of that plethora - I should have enough left over to allow me to clamp objects to the bed for years to come.
I also got my M5 grease zerks today, more stuff that can come off the ToDo list.
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Houston, we have a problem. I thought I would have enough clearance between the bearing block and the base for the zerk fitting - I don't. I need about 10mm for the fitting to clear, I've only got 4mm. Initially I thought I could flip the bearing blocks 180 degrees, and have the zerk fitting on top. No can do, the bed overhangs the fittings - so they wouldn't be accessible. I couldn't do it anyway, there's only 8mm between the bearing and the bed. I can't use an angled zerk fitting either, because they're even taller than the straight fitting.
Soooo..... The solution is simple, I install the grease fitting, grease the bearing, remove the grease fitting, and plug the hole with an M5 set screw - 4 times.
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I added another 20 or so items to the ToDo list, another 15-20 on top of that and the mechanical part of this build will be mostly over. Then I'll get to the part I'm more comfortable with, the controls/electrical end of things.
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Most of the nuts and bolts that I'll need have arrived and I got the bed bolted to the bed/bearing mounts last night. I centered the bed between the rails. The frame diagonals are as equal as I can measure with a metric tape measure, and the edge of the bed is flush with end of the frame, so the bed slots SHOULD be perpendicular to the X axis. If they aren't - well that's future Don's problem. A kind soul on another forum suggested flush zerk fittings. I found some M5 fittings that should fit and ordered them, they arrived today, I should have about 2mm of clearance between the fitting and the base - it worked like a champ.
I'm almost done with the Z axis slider redesign to fit the 300W spindle, something that would have had to happen anyway - might as well get it over with now. I've also been working on the design for the X axis lead-nut block. If I've counted on my fingers and toes correctly, I should have about a 3mm gap between the lead-nut block and the bottom of the bed. I plan on measuring that gap with a stack of feeler gages, and printing a shim to fit. That should be close enough for gubmint work.
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Over the weekend I made the mounting plate for the Z axis carriage and the Y axis bearings. I screwed up when I cut the plate, I didn't cut on the waste side of the line. But that's OK, because I left a 5mm gap between the bearings - so I just squeezed them together a couple of mm. What wasn't OK was the fact that 2 of the 4 holes for EACH of the 4 bearings were in the wrong place. The 2 sets of holes that were perpendicular to the rails had the correct spacing, the 2 sets of mounting holes that were parallel to the rails were not correct. I downloaded the specs for an SBR12UU bearing, which said that the center to center spacing was 28mm - in BOTH directions, Those specs are what I used in my design, and when I made the mounting plate.
When the mounting holes didn't line up I started double checking everything, the drawing said 28mm center to center spacing, the layout lines measured 28mm, the holes measured 28mm on centers. My bearings on the other hand measured 28mm C-C across the rail, and 26mm C-C parallel to the rail. So I started checking to see if maybe I had something different than an SBR12UU bearing. What I found was another SBR12UU spec that matched my bearings. How can the SBR12UU have 2 different specs? I do know how I got 4 bearings that matched one spec and 4 that matched the other spec though. I bought a pair of 1m long 12mm rails with 4 SBR12UU bearings from one supplier. I had to cut the rails to length anyway, so I got rails long enough to get the 2 sets of rails. That supplier didn't offer just the bearings, so I ordered another 4 SBR12UU bearings from another supplier. That also explains why 4 of the bearings needed an M6 grease fitting, and the other 4 needed M5 fittings.
I'm in the process of making a new mounting plate, this time using the correct center to center spacings. The bag of misfit parts will get another donation, but I'm not taking the rap for this one.
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I HAD the mounting plate in place for a little while, it's back off again. Past Don apparently forgot that 2 of the mounting holes for the Y axis lead-nut mounting plate SHOULD have been drilled and tapped into the bearing mounting plate for M3 bolts BEFORE it was bolted in place. I've also discovered that I need to be a LOT more careful in my layout and center popping of the hole centers. This mounting plate turned out better than the first one, but I apparently miss-read the vernier on my marking caliper on one row of holes because they were off by about 1/2mm. A little judicious filing corrected that. The funny part is, that was the same row where I had mistaken a scratch in the aluminum for my layout line and all the pilot holes in that row were about 5mm out of place. Fortunately all the extra holes will be covered by the flathead bolt so nobody will ever know about the boo-boo - right? I really can't wait until when I have this thing running, can tell it to go to point X - Y, give me a center mark at that point, and be fairly confident that's where it's actually located - not just sorta close.
It turns out that the depth stop on my drill press is just about worthless when used to get a consistent countersink depth. The only hole that had a good countersink depth was the first one, the only hole I actually verified, the one I used to set the depth stop that I used for the other 15 holes. Because none of the other 15 countersinks were flush, they all were proud of the surface. I could have lived with them being too deep, but noooo.... I wound up having to take the bolts out one at a time, touch the countersink up with the countersink bit in the hand drill, then put the bolt back in. I don't want to think about how many times I cranked those bolts in and out, before I got the trick down pat of flipping the bolt over and using the head to judge the countersink depth. Remember that judicious filing, and those 4 extra holes? Turns out they are no help at all when it comes time to countersink the hole. They let the countersink wander around like a hotdog in a hallway.
I removed the plate last night and got the hole locations for the leadnut plate mounting bolts laid out. I was going to get them drilled and tapped, but i think I'll hold off on that for a bit. At least until I've got the layout of the leadnut mounting far enough along that I can do a sanity check and see if they'll match.
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I spent most of the day double and triple checking the 3D model against the machine as it currently sits, and found a couple of discrepancies - those got corrected. Last week I picked up a piece of 1/8" x 1-1/2" x 48" HRS barstock, only it was 1/8" plate that had been sheared to 1-1/2" width and I'm OK with that. The problem is that for some reason I had modeled this as 34mm wide and it actually measures at 38mm. I fixed the model, but then I had to be sure that everything was in the proper location. which is not as easy as you'd think. The leadnut plate is centered on the Y axis bearing plate, but the leadscrew is not centered on the plate. While I'm changing a LOT on this machine, I tried to move the minimum amount of hardware from its' original location as possible. When I changed the original Y axis 2020 extrusions to 2040 extrusions, I used the original mounting holes as my starting point. I also kept the original location of the Y axis leadscrew, this was not without consequences. By a happy coincidence the centerline of the leadscrew and the centerline of the Y axis rails all align vertically.
However, the leadscrew's horizontal centerline is 3mm below the horizontal centerline of the 2 rails. This leads to an asymmetrical and somewhat goofy looking leadscrew plate. I've got the layout done on the plate and got the holes center popped. I've even got it cut out, filed, and sanded. The layout lines on the Y axis bearing plates match with the layout lines on the leadnut plate. I'm going to drill an 8mm hole for the leadscrew and make sure that's in the right spot before I do anything else. That'll give me a chance to possibly fix it if I did make-a-da-boo-boo. There's not a lot of wiggle room in some areas, the model shows that I SHOULD have about 8-9mm of clearance between base of the Y axis rails and the leadnut plate. The problem is that I didn't model the heads of the mounting bolts for those rails. I've got MAYBE 2mm, but clearance is clearance Clarence.
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Don, I try to visualize in your posts what you are describing, but often fail. Even a pencil sketch on a photographed napkin might help me "get it". Otherwise, just in general, sounds like you're making progress, and I'm looking forward to seeing the completed mill! :beer:
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Ever have one of those Hokey-Pokey days? The days you take one step forward, one step back, then two steps forward? Today was one of those days.
It started out well enough, I got pilot holes drilled every place in the Y axis leadnut plate that needed a hole. Four of the nine holes were locations that needed to be tapped M3, so I just used the M3 tap drill for all the pilot holes. I needed an 11mm hole, actually I need 10.5mm but a little wiggle room isn't going to hurt. I ain't got no metric drills, what I've got are a set of number drills and a set of fractional drills from 1/16" to 1/2" - by 1/64" increments. So far that has fallen well within the tolerances of my gub-mint contracts. Anyhew, I got the big hole drilled, so I could check the leadscrew alignment with the leadnut plate.
Annnndddd.... It didn't fit as planned. I needed to move the plate about 2mm closer to the Y axis extrusions. Which meant that in addition to being too short, the plate is now also interfering with the mounting bolts for the Y axis rails. Oh Happy-Happy Joy-Joy! There IS a silver lining though, I had a proven hole layout, I knew what needed fixing, and I knew how to fix it. The second time you make a part really is faster than the first time, practice makes perfect I guess.
I knew that there was no way on God's green earth that I was going to be able to drill and tap four M3 bolt holes with everything on the rails, so I came up with a work-around. I took a careful measurement of the distance from the edge of the leadnut plate to the edge of the bearing plate, and clamped the leadnut plate in place. After carefully removing both plates, they were transferred to the vise where a transfer punch was used to mark the center of one hole - didn't want to push my luck. After drilling and tapping the hole M3, I used the M3 bolt to clamp the leadnut plate in place to mark the other hole. Rinse-lather-repeat and all the holes in the Y axis bearing plate are now drilled and tapped.
That just leaves the M3 hole that needs to be drilled and tapped in each of the far side Y axis bearing blocks. Back to the machine to partially reassemble the Y axis bearings and bearing block. I didn't need to put EVERYTHING back together, I just needed the far side bearings blocks tight enough that they wouldn't move when I slid the bearings off the rails. I took the side plate off the nearside of the machine, slid the Y axis close to the end of the rails and removed the near side bearings, setting them aside. I was then able to remove the rest of the Y axis assembly from the rails, clamp it firmly in the vise, and use a transfer punch to mark the hole locations for the M3 bolts. I then removed the bearings from the plate, covered the bearing openings with tape to keep the swarf out, and drilled and tapped the holes for M3 bolts. I then started putting this part of the machine back together - for what I hope to God is the last time.
Anywho, this is what the Y axis looks like now. (vtsteam - I'm usually too lazy/busy/forgetful to remember to take pictures.)
(https://lh3.googleusercontent.com/pw/AP1GczO9me-jA2guUsZfmAdwkaaNfclcMgfpx_6WiHw5fq_YyV0m8Ex848vIn8lCk2qYu76ZXNf0Cl4OwJztdDslKFRHsZcFyynp6HJxOhanvDAvuYBUM6zs_RF3VTxp5wPCWIu5akaLXYKzPVMCYZCjBK45=w584-h625-s-no?authuser=0)
Like I said, the offset leadscrew makes the plate look a little goofy. Everything is just loosely assembled right now, and since I took the side plate off I'll need to align the rails to the bed again. That's not the actual leadnut, I need to build the anti-backlash nut and the leadnut plate together as an assembly. The four M3 button-heads hold the leadnut plate/leadnut assembly to the rest of the Y axis assembly so maintenance will be fairly easy.
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Today was spent putting the Y axis leadnut assembly together. I started with your standard 3D printer anti-backlash leadnut, looks like this when assembled on the leadscrew.
(https://lh3.googleusercontent.com/pw/AP1GczNjZCk1pkmO1BXkKHk_dgff88M7jNE6zoklN5BZjsyFDhpIYvuODYEOBTUZ8jl4IFUOMfiJ06jMMYNazNuDwlZSVT3nljJw1k1Iv6PU1LIDfzWMvz1N1-0GUFAB2tA9RCoWD6Z4fuiPtouVfkNN9api=w469-h625-s-no?authuser=0)
This is just 2 modified leadnuts assembled back to back with a spring between them.. The spring keeps the 2 halves of the nut separated, removing the backlash, and a tab/slot arrangement keeps them in sync. This works fine for the minimal tool pressure of a 3D printer. BUT, and there's always a big butt, any tool pressure that opposes the travel will overpower that wimpy little spring and your backlash is back - don't think that'll do the surface finish any favors.
I remembered that Awesome CNC Freak had modified his 1310 machine to deal with backlash, so I did some digging - and then quite happily swiped his idea. This was the test rig I built.
(https://lh3.googleusercontent.com/pw/AP1GczMmv-oyGUPjjqoSSxuQNenIFxxy_zUJG5SNgeJDchBwgyLCSN2P-RKrnx1tI_KB5pcIbQ5EaZEOz2hNG-Y9eQQE_23C5ic5C6LOu6hEsRG6G3t4oGpBuBTxA2z3aYaqmtAYGnOxJE1iWQ113cS-v_JZ=w469-h625-s-no?authuser=0)
It proved the concept. By using the nut to squeeze the 2 halves together you eliminate the thread backlash, and it's much more rigid. It does take careful adjustment though, you go from free falling to totally locked up in 1/4 turn of the nut. The bolts I used on the test rig weren't long enough though, the nylocks wouldn't lock - going from M3x35mm to M3x40mm bolts solved that problem. The bolts also keep the 2 halves in cync. This is what the business end of the Y axis anti-backlash leadnut assembly looks like.
(https://lh3.googleusercontent.com/pw/AP1GczMYhANqn-tjCNXsW3_XujIfia04uf6Yi-5s59KTHlyypOzVodTYMgytip6TDYNx8vu98R2aXs3MVRB9Rl4mp9K7je6Og9mszkyBimNbjgqQoRzC5MSmWc_Sss-GPVKQlWnVOAy4VR89cMWeAnp5lixN=w469-h625-s-no?authuser=0)
That part will be buried between the Y axis bearing blocks though. This is all you'll see.
(https://lh3.googleusercontent.com/pw/AP1GczNrWuSuOZhjNq4OCP_qo7QLwEscpuSrG-TmJK-jO4EdX8GQ24xYMygb3x2Pd-P-6ZdllGOvY-ed5AP6yj9NxH_fgkXN_0RzCgWLJgoWuwr4S0I7ramDe58jTWsQuwHWz1_WRm6UqlplFraiaVAn57q4=w469-h625-s-no?authuser=0)
OK, OK, if you ignore the bit in the lower LH corner - THAT's what you'll see. Really shoulda cropped that picture.
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Thanks greatly for pics! :beer:
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Thanks greatly for pics! :beer:
I had my old Blueberry flip-phone for so long, I keep forgetting that my new flip-phone has a camera. It doesn't have the anti-blur capability of my camera so sometimes it takes several attempts to get a decent shot.
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I had a couple of 3D printing milestones recently, I started printing with something other than PLA and the P1S glitched on me. Although in all honesty I probably made it worse than it should have been.
I decided to try PETG, and I wanted to get the scaling dialed in to correct for shrinkage. I decided that I might as well be printing something useful to do this testing. My new spindle uses an ER11 collet, so I found an STL for a chip fan that presses onto the collet nut. The friendly Google AI said the scaling factor should be 100.3-100.8%, so I scaled the fan to 100.5% and gave it a shot, way too tight. I scaled it to 100.8% and printed it again. It takes less than 1/2 hour to print the fan - including the 7+ minutes the P1S uses for setup on every print. It was still too tight, but I could force it on the nut. I printed it again, this time scaled to 101.5%. It presses onto the nut, not all the way, but since I didn't design the fan I can only guess the designers intentions. I WAS going to print a fan scaled to 102%, but that's when the glitch occurred. I started the print and left to do something else. When I came back about 15 minutes later I had a bird's nest on the print bed. It happens, so I did what I do when the D6 screws up late at night - I shut off the power and went to bed.
When I got up the next day and fired up the printer it was not happy with me, the AMS was making very unhappy noises. I realized that I SHOULD have aborted the print, then shut off the power and gone to bed. Ain't 20/20 hindsight just wondermus though? I realized that the filament had frozen in the extruder and that I needed to get it out of the hot end so the AMS could retract it and be happy again. But, I needed to do that before the AMS was powered up. I decided to try unplugging the AMS, heat up the hot end, and see if I could pull the filament back by hand - to see if that would work. I did, and it did - so I decided to try printing again. All seemed to go well, until it tried starting to print about 50mm above the print bed. All I could do was abort the print and hang my head in shame wondering "What the Hell did I do to this poor machine?" Before I contacted Bambu Labs and confessed my sins, I wanted to run the initial calibration cycle again. I wanted to see if that would let the printer find its' lost marbles.
I'm proud to report that it worked and the plastic pooping robot is now about 7 hours into an 8 hour print. That print will give me the Z axis rail holder, and the bearing block that will slide on those rails.
Don