Aluminium CNC build (TEP mill converted) by Craynerd

[raynerd]

I know I`m going to get an absolute hammering for this especially off Swarfing, but I started off with EMC2 and don`t have a bad word to say, it got me going and was all free! I would consider myself a decent computer user but having never used linux before, I found EMC2 tricky to get my head around when wanting to do anything but the basic functions.  BUT I did install windows and have since run Mach3 on it. Mach3 was much easier to setup and the user interface can`t be beat! Despite all my tweeking of emc2, I still couldn`t get my motors to move as fast and smooth as I could with Mach3 - which I know makes no sense and the issue must have only been due to my inability to setup EMC properly, but it did show how easy Mach3 was to get up and going and to the best setup!

Anyway... enough on that before I get myself slaughtered by the linux crew! I have no doubt that if I knew what I was doing in emc, I could have got an identical setup than I have in Mach so I blame it on my inability! But on the flip side, it shows how easy it is to get Mach3 up a running with best setup.

Today I attempted a few more gears, big and small and practiced layouts in vcarve. I wanted to utilise wood/space and so attempted to cut a few smaller pinions in the crossing out areas of the bigger wheels. The third round disk is just a spacer washer.



The gear is 150mm and my wood is a scrap I had lying around at just the right size..infact, 151mm gives me little error in my alignment! Screwed the wood down to an mdf sacrifical piece with some double sided tape as well...


I did this in 4 steps:

Step 1: cut all the centre holes, this allowed me to go around and screw each part down so it didn`t pop out and get caught in the cutter at the end of each piece


Step 2: Cut all the pinions and spacer:


Step3: Crossing out:


Step 4: Cutting the teeth


And out it all popped...well, when I had unscrewed it all:




Really enjoyed this little project and learnt a lot.

Chris

[DaveH]

Very nice Chris - well done 
 
DaveH

[Swarfing]

Chris you should not worry about using proper control software, if using girly windoze and mach3 gets the job done then so be it 

You still did a good job and well done

[John Stevenson]

There is a very good thread going on at the moment on the Yahoo DIY-CNC group.
An American Dan Mauch, very knowledge and much respected is trying to get a Gecko 540 running on EMC but it won't run the charge pump correctly.

Three EMC uses, one of them a developer, Kirk Wallace, are trying to sort this out. Dan first posted on March 26th asking for advise as messages to the LinuxCNC forum were going unanswered.
Since then there has been approximately 118 posts going backwards and forwards between various parties for 14 days.

Now if 4 people conversant with Linux CNC can't sort this out in this time then what change does a complete newbie have ?

John S.

[philf]

Chris,

Excellent stuff! 

Now for some metal? 



Phil.

[raynerd]

Phil - Metal is next before I stop any more tests and finish the machine properly -stops etc....

I expect this is probably asking too much, but I`m very much learning CAD and I`m getting OK now for more obvious parts. I know this is only a practice, but I`d love to make a part I want. Could any draw this up for me to scale in a dfx file? However, i want it modifying...I want all the little teeth with only a 3/64" instead of a 1/8" line to the centre. In an ideal world, the hypotenus would then come up at a corrected angle to meet the tip of the next toot, but it actually doesn`t have to..there could be little flats between each tooth. The one deep tooth, at the top of the drawing, would than be 1/8". So basically, the wheel exactly how it is in all dimensions but I want smaller teeth and the one deeper tooth can be like the "standard" 1/16 on the original plans.

I`m away from my normal computer right now which is why I`ve attached the image rather than posted it. While writing my message I have realised this is likely not a two minute job so I appreciate it if any could even just give me some pointers as to how to get that drawn up, I`d be thankful. I`ve not tried a gear yet although with it being a ratchet wheel (count wheel on the clock), I expect it is easier than a normal tooth profile !


Chris

EDIT: Just thinking, I expect i`ll need to use pretty thin bras sheet and a 15deg engraving bit to get a sharpish angle in the corner where the pawl gets hooked. I guess I`m always going to get a round corner due to the radius of the cutter.

[kwackers]

Now if 4 people conversant with Linux CNC can't sort this out in this time then what change does a complete newbie have ?

John S.

If they're talking then things have moved on...
Used to be Linux fanboys were like the high priests holding the knowledge and trying to get help with issues usually just met with abuse and unhelpful comments.

[philf]

Chris,

Is this what you wanted?



The deep tooth at 1/8" looks deeper than your drawing. I've put the three no. 55 holes in the centre of the hub as there was no pcd for them.

DXF attached.

Cheers.

Phil.

[John Stevenson]

This is what I got keeping to the 60 degree limitation.





John S.

[mattinker]

There is a very good thread going on at the moment on the Yahoo DIY-CNC group.
An American Dan Mauch, very knowledge and much respected is trying to get a Gecko 540 running on EMC but it won't run the charge pump correctly.

Three EMC uses, one of them a developer, Kirk Wallace, are trying to sort this out. Dan first posted on March 26th asking for advise as messages to the LinuxCNC forum were going unanswered.
Since then there has been approximately 118 posts going backwards and forwards between various parties for 14 days.

Now if 4 people conversant with Linux CNC can't sort this out in this time then what change does a complete newbie have ?

John S.

First of all, I don't want to pollute this very interesting thread. I'm really glad to see the great results that you are now getting

One can always find an example of what doesn't work with something. I use Linux for everything, principally because I don't want to contribute to Microsoft and their practices. The communal spirit of Linux is important to me. I have never had a problem that I couldn't resolve so far. Apart from being free, Linux has the immense advantage having no virus. Problems. There is of course another very important consideration, "the best system is the one you know".

Regards, Matthew

[raynerd]

John, Phil...many thanks for both your drawings! I think John, you have actually drawn what I want and what I meant to say. Phil, you have drawn exactly what I said....sorry my fault...

I`ll have another go:

The drawing shows 1/8" rim with "normal" teeth at 1/16" depth to the centre. I have asked for teeth 3/62" to the centre BUT then incorrectly, I said:

The one deep tooth, at the top of the drawing, would than be 1/8

... I`m sorry, that should have read the one deep tooth would then be the standard 1/16" from the original drawing. i.e making all the teeth smaller and so the "deep tooth" becomes the standard depth of the old drawing.

However, I`m fairly sure that is what you have done John...!

I`ll give it a bash later today... not sure how well it`ll work as I`m invetiably going to end up with a rounded corner. This could also be quite critical in its failure as this is where the pawl binds to the tooth to drag it around!

[John Stevenson]

OK now we have sorted the sizes out this is the wheel with a 1/16" master tooth.



shout up which DXF you want and I;ll email it.

John S.

[philf]

Chris,

I thought it didn't look right - what's 1/16" between friends?

You're going to have 2 problems I think:

The radius you've already mentioned and the fact that, using a tapered engraving cutter, you won't have vertical sides to the teeth.

You could always relieve the teeth something like (drawn for a 1mm dia cutter):



Cheers.

Phil.

[John Stevenson]

Neat Idea Phil, gave me an idea.

Edit,

Chris has said he wants to use a 15 degree engraving cutter so i drew the cutter and offset the tip by 30 thou to see how big the diameter is when cutting 30 thou sheet. taking a guess here as Chris has said 'thin sheet'

So alter two teeth, the one on the left to give a rad at the bottom as you would get by profiling and the tooth on the right by pre driling with the cutter, then profiling.
Looks like the pawl will have to me modified from a complete angle to a radiused one to fit in.



Comments ? bricks ? flying custard ? muuuuuuuum yummmmy

John S.

[philf]

Hi John,

I don't know if Chris has a 15 degree inclusive cutter or half angle.

Whichever, the wheel will still have non vertical faces which I suppose could be compensated for in the pawl.

Personally, I'd prefer to use a small diameter parallel cutter to do it.

I prefer the look of the radiused bottom rather than the drilled relief on purely aesthetic grounds.

I'm going in the workshop to experiment on the Quorn T&C grinder - I've plenty of broken carbide cutters as blanks.

Alternatively, it's the ideal job for a 4th axis using a 60 dovetail (or fly) cutter.

Phil.

[raynerd]

Phil...

Alternatively, it's the ideal job for a 4th axis using a 60 dovetail (or fly) cutter.

The last time I saw your machine I`m sure you demo`d the 4th axis in motion and you were just looking for the ideal project to really test it out !!!    

-----------

OK, just to quickly clarify how this wheel is being used... it is the count wheel. The pawl attached to the pendulum drags it around and equally the back stop jams up against the teeth lower down to step it around.

The reason I want to change this wheel is because it takes too much drive and lift from the pendulum to step the count pawl OUT of the teeth. The pawl is only 1/32" so actually in theory the teeth only need to be 1/32 deep to catch and lock the wheel and drag the wheel forward. I`ve said 3/32" to give some tolerance but it certainly doesn`t need to be 1/16 as per the plans. The issue is not actually with the 1/16" teeth...it is because the 1/16" tooth FORCES the "deep tooth" to be even deeper and consequently, if the clock stops (which it does infreqently!) it is because it just hasn`t quite got the momentum to slide the count pawl up the hypotenuse to escape the deep tooth. Having 3/32" teeth and a 1/16" deep tooth will mean that the "effort" to escape the deep tooth will be massively reduced from what it is now. Escaping the deep tooth will be mill escaping a normal tooth on the current wheel. This will make a massive difference. The angles that the pawls (count pawl and backtop) are set at also mean this small difference in the normal and deep tooth, it takes a real extra bit of momentum to escape it! Unfortunately, the way this clock works means that the deep tooth comes around right at the end of the cycle when the momentum of the pendulum is at its lowest!!

So after that little rant and explanation, I don`t think either of the two wheel with the circular roots will work as the hypotenuse must be a clean slope for the pawl to slide up to escape the wheel. Actually, I have no issue with the radius at the bottom of the tooth as this will allow the pawl to slide nicely to its escape...however, will this radius cause the pawl to jump over the tooth and not engage against it. It is the pawl dropping into the sharp root of the tooth that drags it forward without popping up over the top.

Not ideal, but perhaps if I just went ahead with the radius at the bottom I could go around the wheel with a needle file and just sharpen it up a bit...however, it does defeat the CNC somewhat!

I hope that has given you some more info in what I am trying to achieve...truth is, I`ve read your posts and now I`m still not sure of the way forward.

My only cutters at present near narrow enough are the 15deg engraver or a 2mm endmill.

[philf]

Aha! Alles Klar! 

So the big clearance on my drawing wouldn't work at all. I was picturing a solid pawl.

John's radiused root should be fine - particularly if the rad is smaller than the diameter of your pawl wire.

The slope would also be better going to a point then it's not as steep.

I've just been grinding a 0.5mm cutter:



The end looks like:



I've ground enough parallel to cut about 1mm.

The trouble is that (according to GWizard) you ideally need a spindle speed of 77,716 rpm at a feed rate of 468mm/min.

Do you know what the maximum spindle speed you can get is?

You'd need to reduce the feedrate proportionally.

You're welcome to try it if your engraving cutter doesn't work.

Cheers.

Phil.

[raynerd]

 
Damn, Vcarve won`t let me plot a toolpath that it knows it can not fit! I`ve taken Phil's attachement and selecting my 30deg inclusive engraving bit set at only 1.05mm in 1mm material depth and it tells me "Error: Check tool can fit into selected vector at machining depth" if I try and cut outside/right.  If I try and cut on the line it will create the tool path so I`m guessing it is doing this because it knows it can`t get into the corner...fair play to it, but that is a pain. If I choose to cut on the line it`ll make my wheel smaller than desired

I`m thinking that 4 axis is the only way to do this properly.

Chris

[John Stevenson]

Try it at 0.5mm then file the rest, you will have a pattern to follow and that bit of brass will file out easily.

[philf]

Chris,

I've just done the preview in Cut2d with a 0.5mm cutter and it's come out OK.



I've attached another 'clean' DXF  the previous one had some arcs left on the points of the teeth from a previous incarnation. (That may have been the problem or maybe Cut2d doesn't worry about fitting into the corners.)
 
Good Luck.

Phil.

[raynerd]

Hi guys, I`ve only had half hour sessions in my workshop recently due to commitments at work and home. But I`m just updating a few of my threads, starting with this one.

Here is the cnc machine as it now stands and I`m pretty chuffed with how it has turned out. I`ve now milled aluminium sheet, brass and of course soft plastics and wood. I`ve also purchased some wider angle engraving tips that have been cutting very well.

I have a big project planned for this machine but more on that in due course.

Here is the machine as it stands:

The flexible cable shield is very good. I must admit, I`ve got a cable I can`t fit through which is stuck to the top defeating the purpose of the shield but it works well and keep everything near:


Electronics are housed in an MDF case with a clear perspex top. Master on off switches for the machine and spindle with the pot also hooked up to the front perspex case.


Hall effect sensor with a collar and magnet on the spindle gives me what seems to be a fairly accurate reading of spindle speed in Mach3. Unfortunately, Mach3 does a very poor job of controlling the spindle directly even with my microcontroller pic controlling the PWM in line with the ESC. I have a dual boot system and EMC2 / linuxCNC has no issue at controlling my spindle speed directly from the software!! Unfortunately, I prefer Mach3 and so I am living with manually controlling the spindle speed but with Mach3 displaying the RPM from the hall effect sensor:


Thanks for looking and all the help I got from various people on this forum when building this machine. It is better than anything I had thought it would be capable of!

Chris

[raynerd]

Hi guys,

Just wanted to show you my latest project. I was going to put it in the wood section but actually, I`ve done no woodworking skills to do this, it has all been CNC!!

I`m laying some parquet flooring in my porch. It is only a small 3m sq area and so I fancied making a little more special by adding some inlays. This is my first effort and more hopefully to come.

I just wanted something simple to try so I choose a star/compass with a N letter. It could be much more intricate but for now I wanted to just go with a single wood inlay. The parquet block is oak and the inlay is in maple.

Using VCarve, which I must say in my opinion is probably the best piece of software to match its quite complex function, that I`ve ever used! I created a vcarve path in the oak block. I then inverted the image and created a v carve path between my image vector and a rectangle I`d purposly added and drawn outside of the material boarder. This then cuts the material in the inverse and you get the image above the main timber level. This takes a lot longer as it has to remove all the extra.



Push the male into the female and glue.




Machine away the excess material and sand level:


OK, only a simple inlay but I couldn`t have even dreamed of doing this by hand. To get the "N" so well pronounced as well. I bet it would take a little more sanding and I would hope that would make the edges even sharper but I`ll leave this for now. I might use it, I might not...I`ll see how some more complex designs come out!

Chris

[micktoon]

Hi Chris , that last project looks realy good , very nice edges between the two woods, like you say you would have to be very good to do that by hand.
  Cheers Mick

[raynerd]

Cheers Mick, got another more complex design on the way now. We`ll see how that turns out.

[John Stevenson]

If you made them with an E for East instead of a N for North you could sell millions in Bradford and make a fortune.