Reply with QuoteI like how you used the angle iron, I have "filed" a few pic's for future reference. Keep the pics comin
Russell.
2-axis ghetto cheap
I've mentioned that I'm doing a super-cheap 2 axis conversion on my HF 44991 mill, and this thread shows my progress so far. But first, a word about my project.
I very much admire the conversions that Hoss, skmetal, Adam, and others have done or are doing. They are done right, and done with a very high level of quality and expertise. In fact, they're done the same way I would have done it myself a few years ago when I was machining for a living, and had almost unlimited resources for materials & machine access. Hat's off to you guys, keep up the great work and updates on your machines!
When I got my mill a few weeks ago, I had no immediate plans of CNC-ing it, until I saw what can be done. I decided to take my project in a different direction: how cheap & easy can someone do a 2-axis conversion? 2 axis is perfect for me, as I only plan on doing limited 2D profile machining on plastics or occasionally aluminum. The way it sits right now, I have about $140 into it. $100 for the complete 2 axis setup I got off ebay, and $40 for the timing pulleys & belt.
Pic 1 shows the incredibly simplistic components I made to complete the stepper mounting. The Y mounting brackets are 1" angle iron, and are mounted to the Y axis hub using the M5 tapped holes that go thru it. Note that NO modifications needed to be made to the machine. I may decide to do some minor mods when I mount the controller and run the cables. I presently have the timing belt tension just about right. If and when it stretches, I'll have to add a belt tensioning device to it. The X axis drive is a simple aluminum shaft that engages the slot in the end of the leadscrew. I opted to use Lexan for the mounting plate because it was readily available and easy to work with. I may at some point make nicer aluminum mounting brackets for both X & Y axis, but first I'll see how it works. Next phase of the project is getting the controller mounted and the cables run neatly. If all works well, then I'll come up with something to shield the belt & motors.
Pic 2 shows the timing pulley: the I.D. was bored out to 20mm, and it simply replaces the number dial.
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I like how you used the angle iron, I have "filed" a few pic's for future reference. Keep the pics comin
Russell.
Very Nice, sweet and simple. I love it!
I can't say I like your setup there blades, I love it.
American ingenuity at it's best.
I love simple designs that get the job done with the least hassle.
That would be a pretty easy kit for you to sell.
Hoss
Gosh, you've... really got some nice toys here. - Roy Batty -- [URL]http://www.g0704.com[/URL]
Hi Blades,
Your Y axis set up is almost identical to what I did as a temporary set up for a power feed on my mill (not an X2). The difference was that I made a new bearing block to add two radial bearings between my thrust bearings. The hand wheel was removed as I didn’t like the idea of catching it when at full tilt under CNC control.
So how do you think your thrust bearings will cope with the side load from the belt tension; do you foresee a problem over time? Reason I ask is if it’s not going to be a problem I may do the same on an X2 that I already have, to use for a CNC drilling machine.
Thanks for sharing btw
John
Did you install more precision ball screws? Didn't notice a mention of that. But then my wife says I can hardly find anything.
Thanks
Hager
Neat! What can you do with the Z axis?
Hey guys, thanks for the kind replys! Wasn't too sure how well this ultra-simplistic setup would be received.
Hoss: thanks man! I definately developed it with an eye towards kitting it.
oldmanhistory: I don't have any thrust bearings on the Y axis, only the OEM setup, and yes, I do forsee problems on a long-term basis, due to the fact that there are no bearings. This is definately on-deck for future improvements. For now, I will just keep it well greased.
Mr. Chips: no, no ball screw for now (part of my ultra-low-cost design). I originally thought about using some new 10 pitch acme screws, but decided with the smaller motors to see how it works with the OEM 16 pitch. Ball screws would have required machine modifications, which I wanted to avoid at this time (part of the KISS principal again)
kanton: no plans for Z axis conversion. There's a lot you can do with 2 axis, but it requires more "hands-on" when running a program. Years ago I ran a 2 axis Tree CNC mill, and absolutely loved it. Was especially nice for drilling hole patterns. You could quickly traverse to different hole locations without concern of Z axis programming. Can't really do any true 3D machining though. Since I'm not looking to get that fancy, the 2 axis will suit me well.
More to come later. Next step is to hook the controller up and see how everything moves, and what kind of power I have at the handles. I already know with the 16 pitch leadscrew that I won't have blazing fast jog speeds. Also have to come up with a CAM program that will recognize the controller board.
Wish I didn't have to work all weekend!
This project is so neat I may want to copy it, but I want at least a three axis machine. Does anyone know if two of these packages could be used together to get a three or four axis machine?
Also, does anyone know which "Two powerful high quality 12 volt 600maH, 1.8 degree, 200 step per revolution motors custom manufactured by Shinano Kenshi" come with this package?
Thanks,
kanton, the motors may not be up to the task of raising the head, unless you have a really good counterbalance setup that minimizes the required lift force. The website that is associated with the ebay sale strangely no longer lists the package on their website. When it was on there, they said the steppers were "... over 100 oz in torque". I know this is well below what most guys are using.
Maybe it would be possible to use 2 of these motors on the Z axis? I guess you'd have to do the math and see if it's financially worthwhile to pursue it.
Last edited by blades; 01-12-2008 at 11:46 PM.
My 1st post – so bear with me.
Has anyone tried installing a Stepper Motor to the Z-axis fine wheel feed using the same method as blades did with his Y-axis and the timing belt?
I know this would not be the best way but would be a cheap way and you could simply use the stock mechanism to engage and disengage for manual use.
Also the low power motor should turn Z-axis fine wheel feed – I think.
Blades, that's an awesome, quick and dirty way to get up and running!
Love it!
OH
I am not a machinest (I think I can't even spell it) but every Mill handle I have turned has has tons of free play when changing directions, and if you tighten the gibs would it still make it usable? How would you manage this? But then possibly there are ways? Pun unintentionally intended I think.Originally Posted by blades
Hey guys, thanks for the kind replys! Wasn't too sure how well this ultra-simplistic setup would be received.
Mr. Chips: no, no ball screw for now (part of my ultra-low-cost design). I originally thought about using some new 10 pitch acme screws, but decided with the smaller motors to see how it works with the OEM 16 pitch. Ball screws would have required machine modifications, which I wanted to avoid at this time (part of the KISS principal again)
Hager
Hey Mr. Chips, it's "machinist"
The typical wear characteristics of a well-used mill will have more slop & backlash in the middle of the table travel area, because that's where most of the use is taking place. The best you can do is to adjust the gibbs (or ways) to eliminate slop on the ends of the travel, then compensate for the extra slop in the middle of the table by gently "riding the brakes" to take up the excess slop. If you adjust the gibbs to have no slop in the middle of the table travel, it will be too tight on the ends of the travel.
If the slop you're feeling when changing direction on the table is backlash, (that dead amount of free-play in the handle when the table isn't moving when you crank), it's caused by either the leadscrew & nut wear & imperfection, or by the bearing preload on the handle that drives the leadscrew, or some combonation of both. THIS, my friend, is where ballscrews REALLY shine! Once they're in and adjusted, backlash is extremely minimal and usually stays that way. CNC and ballscrews belong together like bread & butter. My setup is a cost-driven compromise, because I'm using the standard leadscrews that came with the machine. The primary comprimise is in terms of accuracy, but I'm ok with that.
*** UPDATE ***
Well, today I didn't have to work after all, so I hooked up the driver & PC to test it out.
It works!! Now for the real impression: I was a little disappointed, but not at all surprised, at the lack of power from the motors. It was very easy to stall them out by hand, or by lightly applying the locks. I'm really not surprised by this, and can see why Hoss and others recommend a minimum of 250-ish oz or so motors. You really need a little reserve power to ensure that the motor doesn't stall and miss any steps. These motors I'm using will get the table from point A to point B, and will most likely work fiine for taking very light cuts.
I'm currently only running on the CNC program that came with the board, but it doesn't support G-code, hence no linear or circular interpolation.
In spite of the low power, I am extremely happy with the results of this project so far. It will be well suited for someone who wants to get their feet wet and play around with CNC. It's probably great for a beginner at CNC, but NOT a beginner machinist. I say that because you have to be well experienced at machining to fully understand the limitations of this setup. I also would NOT recommend this setup (kanton, are you reading?) for part of a 3-axis conversion. Don't try and go this cheap if you're wanting 3 or 4 axis, you'll be sorely disappointed. This setup would be PERFECT for someone who works with PC boards and wants to machine traces & drill holes. The program that comes with it would work great for table positioning for drilling hole patterns.
chukkie: great idea! But it would probably require a more powerful motor than the ones I'm using on this setup. That little fine feed wheel doesn't turn all that easy on my machine.
I am still very much committed and excited about this project, and will continue to improve it. I will install some sort of belt guard before I attempt any actual machining, and I also need to see if I can get Mach to talk to the controller board. I will also see what I can do to improve the overall smoothness of the table & leadscrew operation, which will help the motors.
In the mean time, here's another pic, and a VIDEO of it running a test program.
I like the simple approach to 2 axis CNC blades!! Did it take you like 5 mins to make everything! haha
Make sure you keep the bearing blocks, leadscrews, and ways oiled, I know on mine it can be hard to turn when it starts to run dry, especially at the ends of travel.
Are you doing anything to combat backlash? I think I have at least .010" of it on any given axis on mine.
LOL! Yeah, it definately looks like 5 minutes worth of parts, doesn't it?
Good thought on oiling the ways & leadscrews, as they are a bit dry on my machine after taking everything apart and cleaning/deburring. That will probably help a bunch.
Haven't really addressed backlash yet. I will minimize it as much as possible with careful adjustment, and will have to rely on Mach (or whatever program I end up using) to compensate for it. I really don't have that much though, I think around .004 or less when I checked it before.
Blades do you have a link or part numbers for the timing pulleys and belt you used?
I just purchased X2 and I think I will do a conversion like yours but with the Z-axis on the fine feed and larger motors.
Sure thing chukkie, keep us posted!
I got the parts here:
A 6R 3-067037 $5.00
A 6A 3-22DF03708 $11.79
A 6A 3-22H3708 $11.49
Thanks blades
I will start a new thread when I get all the parts in.
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