Ask questions about and discuss the CNC Mill project here.
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Hi I am considering this project for my own use. Precision Matthews does not have a owners manual online yet for the variable speed model. I was wondering if you had some pictures of the belt drive with the cover off. I also was hoping for some pictures of the spindle motor nameplate. Just wondering if it’s single phase or three phase. I think I read in your project that you are considering being able to control the spindle speed with your CNC software. I am considering this too but don’t have any idea what type of motor is on the machine.
Nice project thanks for posting it
Hey TCandee,
Thanks for posting on the forum. I am at work now, so I will edit this response with more details when I get home, but unfortunately, I can’t get the name plate off without taking off the VFD because the sheet metal wraps around the left and right side of the spindle head. However, the motor is 2 HP and 3-phase. Just so we are on the same page, you need to 220V single phase to power the VFD and subsequently the motor.
There is no encoder on the motor, so you can’t do rigid tapping, but you could control the general speed of the motor by connecting the MESA board to the potentiometer on the spindle.
Does that help?
Sweet. I was hoping it was 3 phase. The 833t is a 1PH motor. I want to switch to a sensorless vector VFD and drive it with a centroid acorn board. Thanks for the info.
I converted a 25MV already and added a power drawbar that could be run by the acorn if I had an ATC. I started building one but that was the easy part. Programming it to work with acorn is a bit out of my league. The PDB should
be real similar for the 833tv.
Todd Candee
Would you care to share a picture or two of your converted 25MV? I would love to see it.
Also, if you go through with converting the 833TV (or any other mill) if you would consider posting your progress on this forum that would be much appreciated!
Best of luck!
I will get some pictures to you as soon as I can. I also converted my pm-1030v lathe to cnc. This one I did from scratch. The only place I found a conversion for this lathe was a place I had had bad luck with before. Seems to work
well. I haven’t had a chance to use it much yet. I’ll post those too. I use closed loop hybrid steppers on this one. A lot more $ but probably worth it. I wouldn’t use Chinese leadshine clones next time though. They can be tough to set up or really easy.
Guess which experiment I had!!! They work now but after a lot of hair pulling.
Todd Candee
A CNC lathe on is on my list of future projects! Would you be interested in sharing BOM and CAD files for your conversion?
Sure. I’ll try to get them together. I did not take the time to completely draw the lathe but most of the parts I had to make I do have files. What format do you prefer.
I used a groschopp.com small frame 3ph motor on this and my 25MV. 1.12hp controlled by my acorn boards. They are only 4.875” square.
Todd Candee
If you had fusion files that would be great, but STEP files are fine as well.
Do you have a part number for the motor? And how did you do the indexing of the spindle/motor?
Sorry for all the questions. I havn’t done much research yet, but my few quick googles havn’t turned up any conversions of the pm-1030V, which is one of my top choices for a lathe conversion. It seems fortuitous that one of my first forum members would have a working conversion!
My records are quite hap hazard I will give you as much as I can but I did this conversion on the fly with no intention to repeat it. The spindle motor # is 6219. They don’t really like to build these one at a time. Last time I called
I got a no. Then called back and talked to someone else that would do it. You can order it with just about any diam. Shaft. The big box on the side of the motor can be completely removed. Good little motor. They offer a drive for it as well and a signal
isolator. (very important) Do some research on this. You can’t always just hook up a 0-10VDC output from a controller directly to these drives. Something about ground loops etc. Above my pay grade. I wish I had tried a sensorless vector VFD first to
see if it improved the low speed torque.
As far as the encoders on both the mill and lathe, I made mounts that read it directly from the spindle. If you don’t plan to use the different belt ratios that are stock on both machines then the encoder could be on the motor as long
as the ratio is 1:1. I don’t recommend this because I ended up needing the lower gear (In fact I made new pulleys for the mill to get a 3:1 ratio and a 1:1) for Rigid Tapping. Of course the gear change is manual and I have to incorporate stops in the GCode
to allow for this. On the mill I incorporated the encoder into my PDB. On the lathe I utilized some of the gears that came with the lathe so get a 1:1 ratio from the gear on the spindle. Pictures will show this better and I am going to change it anyway.
It is just too loud. Going to replace the spindle gear with a timing belt pulley and drive the encoder from that.
Cant upload step files. says image files only.
Well… this would be a huge a bummer if you couldn’t share CAD files on this forum. I will look into that.
For now, would you mind sharing on wetransfer? You can just send it to my email: dflo@drdflo.com
Man you are a wealth of knowledge. I hope you stick around the forum. I am excited to see your pictures of your lathe and mill.
I would say that I am still a couple of months away from a lathe conversion. I have been itching to build a plasma cutter for some time now… You wouldn’t happen to have one of those?
It took me a really long time to convert the mill. I did it the hard way by putting the x axis ballscrew inside the carriage. If you look up ProCutCNC. they have a kit. I would not trust them!! I converted my PM-25MV with one of their kits and they lied about no saddle modification required on purpose to sell more kits. Ended up using an angle grinder since I had no other means. The ballscrews were garbage too.
Anyway, their w axis ballscrew is on the backside of the cariage. This would be much easier but I think it puts a lot of stress on the BS. My way is difficult, expensive and takes longer.
I have the files ready. I will try to package them and email. Pictures to come soon.
Yah I was very happy with the kit I got from Bruce Nelson over at Heavy Metal CNC. Converting a mill to CNC is such a niche market that these “businesses” if you can even call them that use cheap components to maximize profits. Fortunately for me, Bruce sent over a quality kit and stood behind his product.
Some people have been teasing me for using a kit for my mill conversion. So when I buy a lathe I will make all the parts on the mill
Its not all its cracked up to be. Takes an enormous amount of time designing the kits. quality parts are expensive when you are buying only one or two. In the long run I think buying a quality kit is the best way to go unless you need specific things that are not offered. You did fine, and documented it well. Trust me, you were up and running months before you would have been if you had made it yourself. Plus, what if you don’t have a mill and lathe to make the mounts??? Kinda hard to do it yourself on the first mill!!!
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By the way, the PDB was by far the best upgrade yet on the pm-25. saves a lot of time when milling a part with many tools. I can’t take credit for the idea and the basic design. this was a Haas plan originally. I purchased his plans and got familiar with it and designed it from there. I used the tormach belleville washers since I am using the tormach tts tooling. This simplified the calculations to make an off the shelf washer combo work.
The PDB should be very similar on the 833tv. the top of the spindle will have to be threaded like it is on the 25MV or something else. other than that it should be identical functionally speaking.
I located 2 used air cylinders that should work on a PDB for the 833tv. I had to buy the pair. If you would like to buy one for your build let me know. Only $125 plus shipping. I will be testing it on my mill once they come in to make
sure they are strong enough. They are on paper but that has proven wrong before.
If you have success with that cylinder, then I would be happy to take it off your hand for $125. Keep me posted. I probably won’t get into a PDB installation until the summer.
Cool. Still waiting on delivery.
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These air cylinders are too big. I must have looked up the wrong model #. Anyway. I’ll probably order the fabco air cylinder.