MadModder
Gallery, Projects and General => Project Logs => Topic started by: shipto on March 11, 2014, 06:37:40 PM
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Everything I want to do requires slides of some sort or another. I have made slide before by endless hours of lapping crude steel plates but this gets tiresome.
I have decided to have a go at a project which will hopefully make the process a little less tiresome and make a surface grinder, I am going into this with low expectations and the hope that it will at least make the lapping last hours rather than days.
I have started by concentrating on the X,Y movement for the moment, I already had a couple of 8mm bars salvaged from printers and some linear bearings to suit them which I brought a while back with the intention of making a reprap printer. so these where drilled and tapped for 5mm bolts each end to fit into the housing for the front to back travel. I would prefer something more robust but if this works well enough it may be able to make better for itself. I first made it with just a front and back but then thought that it might flex a little too much so made a square frame to hold it steadier.
I made some bearing holder blocks for the top of the runner, this will be a cantilever type setup.
Next I needed to make the lower runner bearing holders, they are slotted on the side to adjust the table for squareness I still need to make and attach the blocks to do this adjustment and lock it in place. 5th picture shows them attached to the underside of the table and 6th picture shows the table on the bar I am going to use for the runner.
Hopefully tomorrow after work I can sort out the adjusting blocks.
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Should be a good build!
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I hope that you are going to put some boots on those slides to protect them from dust and grit. If you don't the grit will play havoc with the smoothness of movement.
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yep rubber wipers and brushes as well as guards to hopefully stop anything getting under the bearings.
Had a little time to spare at work today so made some parts for the frame pictures show the base and upright bits going out to shed after pointless to get the blocks done.
Done!
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Got framework home and spent a little time in the workshop, I was sorting out the main runner plate. The picture shows the pilot drilled plate in place one the frame (sorry for the rubbish picture but I didnt have proper camera with me)
its will have 3 bolts pushing against the plate to get it lined up properly and 6 bolts to hold it to the frame and also eliminate any twist in the plate.
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Loosely bolted together but not set up yet and I have to say I am very pleased with how smoothly the table glides along on this plate. Dont want to jinx it but maybe it will give good results after all.
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I have been trying to work on the gears for the feed screw but forged ahead without a clear idea in mind about what i needed and as such I have worked myself into a corner.
I am now thinking its a scrap it and start again job, however the gearing I have found should (if I have done my maths properly) give me a little over 0.1mm per full turn of the handle I just hope this will be fine enough control.
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Many a grinder has two speed gearing, as the fine feed needed is a right royal pain if you need to move a significant distance while setting up. On my cylindrical and also my surface grinder you pull out a knob to engage a coarser feed. Perhaps you could incorporate something similar ?
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Many a grinder has two speed gearing, as the fine feed needed is a right royal pain if you need to move a significant distance while setting up. On my cylindrical and also my surface grinder you pull out a knob to engage a coarser feed. Perhaps you could incorporate something similar ?
Its not a bad idea actually if I can figure out a way of driving the second stage of gearing direct then that would bring the travel to .5mm per turn and would certainly save a lot of handle turning.
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Not sure why you think it's a scrap and start again job as you didn't say. Or I didn't read carefully enough. From my looking at the last pic, if the gear plate attached to the lead screw is rotated 180deg it looks like it would line up close enough to allow fixing of the two plates so the gears mesh ok. Of course the way you have it may be what is needed for mounting. Good luck with whatever you decide - tis all a learning experience. Think of it a practice if it helps.
John B :mmr:
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Why don't you use a sliding gear that way you could have the fine feed and the more rapid travel?
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Theres much I would like to do but I am working on a shoestring budget (otherwise I may as well just buy a old surface grinder) with salvaged parts for most of the project. The gears are out of angle grinders and a drill, the screw is from a van jack etc.
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My friend has a old surface grinder that the table traverse is done with a wire (cable?) no thicker that a moped/bike gear/brake cable. And it seem to work.
If you can find a worm gear for slow speed, such as windshied wiper motor to turn drum (for cable feed), fast manual set would be pretty easy if the cable is tightened with a spring. Just a geometrical lock against the spring load, like a tool box spring lock or such?
Pekka
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My friend has a old surface grinder that the table traverse is done with a wire (cable?) no thicker that a moped/bike gear/brake cable. And it seem to work.
If you can find a worm gear for slow speed, such as windshied wiper motor to turn drum (for cable feed), fast manual set would be pretty easy if the cable is tightened with a spring. Just a geometrical lock against the spring load, like a tool box spring lock or such?
Pekka
Its not a bad idea however I have plans for the left-right back-forward movement of the table which will make it a set and forget machine. Definatly worth remembering for the future however :thumbup:
This weekend had a fair bit of time to spend in workshop working on the gearbox for the lowering and raising of the grinder posted a few pictures which will make sense once I complete the bits and put it together.
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PekkaNF you have really done it now :hammer: I was merrily making this gearbox when I started to think about your comment and had a eurika moment followed by a :doh: for not thinking about this before.
A much better way which would solve both the problems with feeding the grinder to the work and having a course feed for setting it close. If I can A) get hold of the correct tap for the screw I am using (possibly a 18X4 LH trapazoidal) and tap the center of a worm gear or B) turn the nut I already have and press it into a worm gear, I can lock the thread at the bottom to use the fine feed or let it free and turn the screw for the course feed, something like that shown in picture except the screw could be locked off rather than fixed.
I hope you get the idea of what I am thinking.
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Made some good progress today (thanks mostly to the word NO! long story) anyway I started to set things up better than they were, the main runner plate is set as good as can be until I make a few cuts and see how it is grinding. started to weld the frame to the base but ran out of wire before I had finished tacking it so its still clamped for now until I get more wire.
Also started on the up/down for the grinder its just a simple slide using angle irons and a little bit of flat for a gib. It all seems to go together well. The gearing for the screw for this is well under way too but i forgot to take pics of just that so theres one job for tomorrow. :D
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Progress :ddb:
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I'm enjoying your shoestring Grindy thing!
Regards, Matthew.
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I stopped short of calling it a surface grinder because I have seen some get quite elitist about them :D
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PekkaNF you have really done it now :hammer:
What I did now? :) I mean I live for things like that.
A much better way which would solve both the problems with feeding the grinder to the work and having a course feed for setting it close. If I can A) get hold of the correct tap for the screw I am using (possibly a 18X4 LH trapazoidal) and tap the center of a worm gear or B) turn the nut I already have and press it into a worm gear, I can lock the thread at the bottom to use the fine feed or let it free and turn the screw for the course feed, something like that shown in picture except the screw could be locked off rather than fixed.
I hope you get the idea of what I am thinking.
To tap trapezoidal is not very easy and taps are not exactly cheap. Also threading small ID trapezoidal thread is no fun. Buy the nut and make it do if you can.
I think got your idea....you want to do fast traverse by turing the screw, and (slow) feed by using worm drive. Nifty. You need brake/lock for the srew tough, but that should be pretty doable. Simplest form might be extra nut on the tapezoidal spindle to lock it imovable to the frame.
Pekka
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Went with the altering the nut option in the end (see above) as wife couldnt get me the right sized tap it seems to be a special thread which are more expensive and harder to get hold of, no matter though its all going in the right directions now :thumbup:
As for locking the screw to use the fine feed I am simply going to have a locking bolt contacting directly with the screw it wont hurt if it chews it a little as it wont effect the feed.
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what a week :doh: car failed MOT last friday, which I expected but thought it would be too expensive to get through which it wasnt just cv boots, dodgy handbrake, drop links and a sidelight. do you think the bloody cv's would split from the shafts anyway what with that and helping a friend out with a pocket bike i didnt get much done to the project.
what I have done i havent taken pics of but I will get to it and I am pondering what to do about movement backwards and forwards. Side to side is easy I just dont know whats best for the other.
thoughts so far:
1)ratchet and pawl system turning a thread
2)very slow motor turning the thread (this would mean the piece would be moving in two directions while wheel is grinding might cause problems?)
3)stepper motor with either a thread or belt (a little bit more complicated but nothing the arduino couldnt handle)
opinions welcome :smart:
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Why not just use a bike chain fastened to both ends and hooked up to a stepper to drive them back and forth the same motion as a printer. To advance the table at the end of travel (possibly setable) it could advance the gear 1 or x amounts of teeth.
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Why not just use a bike chain fastened to both ends and hooked up to a stepper to drive them back and forth the same motion as a printer. To advance the table at the end of travel (possibly setable) it could advance the gear 1 or x amounts of teeth.
If I choose the stepper motor route I will probably do this although maybe with a toothed belt rather than chain
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Traverse?
You may want to have a look on this project:
http://www.metallmodellbau.de/MINI_BONELLE_II.php
There are few pictures of omega drive type application halfway down the page:
http://www.metallmodellbau.de/pictures/MINI_BONELLE_II/MINI_BONELLE_II_504.JPG
Now, there is one thing you may want to consider, these relatively flexible drives are good for upphill or climb grinding as it happens on tool sharpening, but I would research and think to use this on surface grinding....analogous to up/down hill milling. You get by when you grind up, but on the return stroke you need very rigid grinder/drive or a ability to lift the grinding head during the return stroke. Maybe you have this already devised? I didn't fully follow all details.
Pekka
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I really like that idea pekkanf and think thats probably the way I will go. as for the up?down hill climb I am going to use a mechanical method so it should be solid enough to cope, soon all will become clear.
Today I started by taking a car cam belt idler and removing the outer bit and remaking it so it fitted into the center of a flywheel this will have the variable mechanism to move the table left and right. Then I made the shaft to drive it and started the housing for this, the picture for this i will post tomorrow.
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Well did most of the housing today just need to clean it up for the sake of looks (not that it will be seen now i think about it, it will be covered by a guard). Only had a small amount of stock so the bearings are not totally enclosed but this will not matter the housing is merely holding them straight they will be held in place by the shaft itself.
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Progress has been slowed due to working on getting a vw campervan to mot standard but I have been working on getting the left to right mechanism going and so far have done the top pivot and bottom slide. The bar I currently have connecting them is a bit of extruded aluminium which may not be man enough and need changing but I will see.
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I've been enjoying reading this project! :thumbup:
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I've been enjoying reading this project! :thumbup:
Thanks.
It is still ongoing but at a slower rate as other things must take priority while the weathers good :bang:. I did however mock up the drive for the left to right motion and decided it wasnt geared down enough so I am working on putting another level to further slow it down. Havent taken any pics as its not finished yet but maybe before the weekend is over.
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I decided to take a break from the chores I have to do on sunday and get some work done on the left/right drive :D I think it should be about right now but if I need a bit slower I can increase the size of the larger v-belt pulley.
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so I have decided I do need a bigger pulley mocked it up today to see it running.
the video makes it sound a lot noisier than it really is but the squeak once per cycle is the belt slipping slightly when it has to stop the carriage and reverse it, hopefully higher gearing will solve this. The bar you see is only a temp when I am happy I will get some rod ends.
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Cool! :thumbup:
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Supper :thumbup:
i love the shaper type movement must get back to to building my gingery shaper.
jon
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changed out the pulley and its way more managable now so just for fun I decided to do a little test :)
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That's fun! Looking good!
Regards, Matthew
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Very nice!
When you'll have tested and adjusted it would you publish a bit of info how flat surface it produces. It looks pretty good.
Pekka
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I will do my best but I don't have much equipment to measure it accurately the best I could do would be to lay some paint on the granite chopping board I nicked of the wife and show the results of that.
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I am fairly happy with the left/right movement now and its time to turn my thoughts to the back/forward which for the sake of less typing I will now call X and Y.
I have stripped down a old 9.6V drill a friend gave me and salvaged the motor and gearbox. Then I stripp down the gearbox and sawed the shaft shorter before facing it off, drilling and tapping the center for a m6 screw.
Next I made the mount for it from a block of aluminium, still have to drill and tap the block to mount it on machine but will do that after I work out the rest of the mechanism.
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Had to gather together some of the bits I threw away as I forgot to take the torque limiter mechanism into account, I could have just locked the mechanism but thought if I could find the bits it would be a handy function. So found them and installed them, then mounted the setup on the table.
Only problem now is that I am getting a bit fixated on this and am neglecting to do the jobs I should be doing, example I have had a replacement wheel arch for the camper for nearly a month now and not got it on the vehicle yet oh well :Doh:
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It's great to see some animation! :thumbup:
I've been puzzling/ following. But have had nothing to add...... :scratch:
Looking/ sounding good. Well done! :clap: :clap:
David D
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Shipto,
... do you think the bloody cv's would split from the shafts ...
The reasoning here is that a split cv boot will throw out all the grease and this could cause the joint to dry out and size up.
Would you want a drive shaft to suddenly start thrashing about when you are driving along ?
Interestingly, it is only the outer boots that the tester is worried about.
Dave.
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Shipto,
... do you think the bloody cv's would split from the shafts ...
The reasoning here is that a split cv boot will throw out all the grease and this could cause the joint to dry out and size up.
Would you want a drive shaft to suddenly start thrashing about when you are driving along ?
Interestingly, it is only the outer boots that the tester is worried about.
Dave.
Had to look back to see what i had said here, I wasnt questioning the reason for cv boots failing but commenting that I couldnt get the cv split fron the shaft to replace the boot, didnt go into much deatil because its not a car forum but i ended up having to take the shaft completely out and stripping the other side to get them on.
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No major progress today just added the block for the screw.
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Shipto
I have a chain set up that moves to the right then turns and goes to the left. I can kind of draw up something if you would like to see it. I found the mechanics when I tore down a ink tray mixer on a printing press. It's not anything hard and could possibly be able to set the two point on reverse direction to what you want. Let me know and I will try to make a sketch.
Nelson Collar
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Shipto, just watched the video.I love a good contraption,and this is a wonderful contraption :clap: :clap:
......OZ.
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Thank you nelson I would be interested to see what you have and thank you manxmodder the contraption should be ready to be brought into full operation pretty soon. I am talking to a guy about controlling that Y axis and he may be able to donate a surplus to requirement plc for me to play with :D
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I'd just use a starwheel on a threaded shaft every time it passes over the wheel it advances by how many pins turn the rod.
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something like this principal
(http://i1322.photobucket.com/albums/u577/tom_osselton/Photobucket%20Desktop%20-%20TOM-PC/boringbar_zpsfc6381c2.jpg) (http://s1322.photobucket.com/user/tom_osselton/media/Photobucket%20Desktop%20-%20TOM-PC/boringbar_zpsfc6381c2.jpg.html)
It would not be hard to setup on a table with setable reversing switches to control travel and the feed rate would just be set by the number of cogs and the pitch of the thread. The table going back and forth for two passes would advance it one step sideways the cogs would have to have a ratchet effect also.
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I was thinking of a mechanical solution at first tom but after much thinking I decided this was by far the easiest way to do this part of the build, didnt expect to have a pcl to play with though was thinking arduino would be used (may still use arduino as I have never used a pcl before and not sure about programming it)
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Bit off topic but since I dont have anything constructive to do with grinder I decided to put the wheel arch on the camper.. finally.
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How did I miss this thread?? Very cool!
Eric
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:bang: Been a bit quiet last few days as I have had to take a crash course in ladder logic to operate the plc, actually its not too bad once you get your head around it.
To start my main problem was I kept thinking of it like basic computer programming but afterwards I started thinking about it like a live rail and earth rail.
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Just remember that ladder logic developed to replace umpteen relays, so yes, think of two power rails with contacts and coils between them in intriguing combinations
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Been busy making power supplies need 24v for the plc and controls 12v at about 3amp for the y axis motor. Took a little time to work out the panel too (pic). From top left it is Grinder start/stop, X axis start/stop, then Y axis start and Y axis stop and the final 2 yellow are to bring Y axis backwards and forwards. Need to get some nice labels now.
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wiring or the beginnings of it anyway. Knew the wiring harness from my old fridge freezer would come in handy :)
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:doh: kept looking at the panel and thinking theres something missing but dismissed the idea as me being daft, Then last night it dawned on me I havent put the speed pot for the X axis on there. Going to have to decide on a resonable position for it but think its probably going to look out of place wherever I put it now.
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Shipto
I drew up a working that I said I would try to get to you. Well here it is and I hope you can understand my scribbling.
Nelson Collar
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Thanks nel2lar I think I understand what you have drawn and its worth filing for future use.
The machine is getting so close now but all the wiring is taking me some time not to mention that i finally got the welding on the camper done just need to put it all back together then gather a few thing and I will be ready to mot it (fingers crossed).
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Managed to get a fair bit done this weekend, I have put the rail for the y axis limits which will allow me to set the travel. The wiring for these limit switches and the power for the motor driving the table travels up the arm.
However there is a problem with my plc programming the grinder and Y axis is fine but I cant get the X to perform as expected and I am not sure why. Is there anyone who knows about easy logic on the board?
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The plc programming has been a bit of a headache but I have finally sorted it and everything is working as expected now :ddb:
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Decided to give it a little test by grinding the table top I am quite pleased. About the straightest thing i have in the shop is the ruler off my set square which I wouldnt guarantee but its probably close enough for my needs and the red area in second picture marks a place where I can slide a rizla paper under the ruler. everywhere else is too close to get it under.
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That's great Shipto! :headbang:
I think the wheel needs racing, for an improved finish. :smart:
By the way...... I'm sure, it's your rule which is bent....... :thumbup:
Love it! (http://smileys.on-my-web.com/repository/Respect/respect-061.gif)
David D
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Thanks Stilldrillin the wheel definatly needs changing the one on there is pretty bad but I will get another one once I have mounted magnets and made a jig to true it up. still have much to do like the mentioned magnets and guards which will include wipers and brushes to keep the guide rail clean. need to figure out how I am going to keep the muck from going under the table too, The linear bearings have wipers of their own but I still want to stop as much as possible going onto rails.
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A good vacuum system will do the trick.
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A good vacuum system will do the trick.
Thought about that but the noise would be horrible.
However I have been thinking about a canvas cover for the ways which I will try to describe because I would like opinions,
where the canvas is protecting the way it will fold around it but when off it will fold around the backsomething like this (see pic)
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Have you looked a bellows http://www.arceurotrade.co.uk/Catalogue/Machine-Spares/Machine-Bellows , I have the rubber ones and they squash down well .
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I have a little experience on dust issues on round quides.
I would start from two ideas:
* Prevent excessive fallout on quide rods, a little shield on top, maybe an ash vacumcleaner or something (you don't want to set shopvack on fire).
* keep quides dry and clean.
We had one system with plenty of abrassive dust, few hardened quide rods and plenty of ball bearing bushes. When lubricated regularry, the bushes wore out no time. They lasted about as long if they were never lubricated or lubricated with "dry" lubricant. But they life was varied even more (like factor of five) depending how often the ways were cleaned on shopvack. Claning with pressurized air was worse than no cleaning at all!
It's rally hard to prevent ingress of fine dust. IMHO non pressurized belows are not worth of it. If you get any dust/grinding paste in, it's really hard to get it out.
Commercial manual grinders seem to trust on design, that minimizes dust fall out on quides. Labyrinth seals with pressurized air purge are pretty involved.
On that type of machine I would put some shields and some wipers/lipseals to prevent any bigger that rodent size particled entering into linear bearings.
Pekka
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I am less worried about the linear bearings they have rubber wipers fitted and I plan to fit brushes to sweep them as the table moves along, with that I am looking into a method to block the majority of the dust even getting there in the first place. The main problem is the top of the way at the back, I am worried about a build up of dust which the bearings there will run over thus making the whole thing less accurate by whatever thickness the dust is.
Here again I am planning to use brushes the sweep the rail. the canvas Idea if I can get it to work would stop most of the dust getting there making the job of keeping the rail clean easier for the brushes.
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The canvas sounds a good idea to prevent the majority of grime getting in.
I just wondered if you had also considered placing a couple of neodymium magnets in a location where they would capture a lot of the metallic dust produced while grinding is taking place......OZ.
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Funny you should say that, I have yet to take photo's but I have fixed the magnets to the bed and tried a bit of grinding and the magnets did seem to be catching most of the grindings.
editted to include pics.
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Have moved on a little, brought the rod ends to replace the temporary arm and made a start on the guards.
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I have been testing the grinder out a little over the past week and come to some conclusions:
The grinder itself is too slow, too under powered and not sutable for prolonged use it overheats quite a lot.
It will suffice to allow me to make the parts to improve it, I am going to reamake that part using a .55kw motor and shaft with a variable pulley to set the speed between 3000rpm up to about 6000rpm. I also intend to make some adapters to hold the grinding disks I need to buy so they can be balanced before being placed on the machine. hopefully this will mean I can have a variety of grits.
Also something needs to happen with the main slide the bearing are digging in a lot quicker than I thought so I am thinking that if I can get some straight thin hardened material that I could fix to the areas where the bearings run that should do the job.
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Been busy working in the house keeping the treasurer (wife) happy but had a day off today and made some progress. The grinder has been stripped of its electrics and is ready to be mounted on new slide mechanism. Also made a start on the balancing adapters for the wheels.
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Bit more done :) Over the weekend I knocked up a couple of slide rails and got the motor plate mounted on the slide rails.
pic one shows the slide rails and on the floor is the motor thats going to be mounted (along with the evidence of my bad smoking habit :wack: ) and pic two with the motor mounting plate in place.
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Finally got it back to working condition and I am very happy with it now the extra speed and power has made a world of difference. Once I get a new wheel and get it balanced right the finish should be nice.
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Looking forward to seeing the latest version :coffee:
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Looking forward to seeing the latest version :coffee:
Apart from a new wheel and some guards your pretty much seeing it. I do have to work out a balancing fixture.
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Looks to be working well, you must be very pleased. What infeed depth were you using in the video? It seemed rather a heavy cut, you need to be careful not to overheat the work. It'll expand locally thus taking more off and leave an uneven finish when it cools. At the extreme the work expands, makes the cut heavier and burns the work. Amhik.
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Looking forward to seeing the latest version :coffee:
Apart from a new wheel and some guards your pretty much seeing it. I do have to work out a balancing fixture.
Oops, I have a temporary browser problem with Flash and Youtube, and didn't realize your post included a video. Hope to have things fixed shortly... :doh:
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Looks to be working well, you must be very pleased. What infeed depth were you using in the video? It seemed rather a heavy cut, you need to be careful not to overheat the work. It'll expand locally thus taking more off and leave an uneven finish when it cools. At the extreme the work expands, makes the cut heavier and burns the work. Amhik.
It wasnt taking as much as it looks, I lowered the head with four turns of the handle which I think is around .01mm but I need to rig up a dial to see the exact movement per turn. I might do that tomorrow after work because it has been so long in the making I have totally forgot how many teeth are on the worm gear, sure it was around 80 but cant be sure.
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I have a few little problems one good one potentially bad. The good one is that my wifes work has been having a clear out, I was given a metal cabinet and wait for it A 16" ECLIPSE MAGNETIC TABLE :ddb: now this is too much bulk for the existing setup so a redesign will have to be on the cards now. The other problem is that a stray bit of swarve got onto the left/right controller board and blew a track :doh:. I just hope this is all it did.
Couldnt look at it this weekend however as I had to get some lights fitted into grand daughters doll house.