PM-833 with Heavy Metal kit

Sorry, life threw me a couple curve balls a couple weeks ago. When I get back under control, I’ll get that info for you.

No need, but I very much appreciate your response. Here’s the actual parts I needed:
Part Numbers: A 6A 4-14DF05016, A 6A 4-18DF05020 & A 6R 4-033050 on Catalog | Designatronics Store | Stock Drive Products/Sterling Instrument

Did anyone see the Heavy Metal site appears to be down indefinitely? Any one know what happened? I was going to use them for the 833 conversion.

flyingamortgage mentioned in his post on Jan 16 that Bruce died late last year.

@Dr.D-Flo do you offer your own version of PM-833TV cnc conversion kit for purchase? Heavy Metal CNC’s website is indefinitely down at the moment.

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Unfortunately, due to the irregularities of the PM-833TV (and other import mills) castings, Bruce Nelson had to make slightly different brackets for nearly every mill that he sold a conversion kit for. He told me that it was very time consuming and there was a lot of wasted material and machining time. I would be willing to offer a conversion kit under some special conditions:

  • You provide measurements and pictures of the hole alignments
  • I ship you 3D printed brackets and you make sure all the holes line up
  • After confirming the dimensions are correct (this could take several iterations of printed parts), I will machine the final components.

This could be a bit of a lengthy back-and-forth process, but it would result in good alignment. The cost would be $1500 for brackets + doublenut ball screws. This is at a premium because I would be purchasing in small quantities and would not be manufacturing multiple sets.

This is perhaps only for those who are desperate, but you can shoot me an email ( if you are interested.

Hello Sean,

I finally got my PM-833TV. I was about to start the CNC conversion with the Heavy Metal CNC conversion kit and remembered your gas strut project. Since I will be using a 1700 oz. closed loop stepper for the Z-axis, it may not have enough torque to lift the head without the aid of the gas struts. Therefore, I plan on manually machining the brackets for the struts before disassembling the mill. Can you please confirm the following:

  1. That you used the threaded holes that were originally used to lock the Z-column (see below red arrows pointing to handles).
  2. That you used smaller holes on the other side of the mill that are currently holding the power cord in place (see red arrows pointing to small threaded holes.

One a side note, I saw the posting with regards to the fact that there is lots of variation amoung the PM-833TV builds. I was just installing a power draw bar kit from Greg Priest and found that the holes in the mounting plate do not align with the mill. I hope my CNC conversion goes a bit better.

Thanks… Richard

I used the threaded holes on the top and bottom of the z saddle that are used for the rubber and pleated way covers. There are four pieces to my bracket: 2 horizontal fastened with the way cover holes above and below the saddle and 2 verticals fastened to the horizontals.

Very clever idea! Thanks. I will be making these brackets on the mill before I convert it to CNC. This will be my first project since using a mill in high school (40+ years ago). I can assure you that mine will not be as pretty as yours!

Thanks… Richard

Sean… Thanks for the great idea. Since I will be using a 1700 ounce closed loop stepper, I really wanted to use your gas strut concept. I realized that I had to make the brackets BEFORE I disassembled the Mill as this stepper may not be able to lift the weight of the head. With the machine sitting on the floor of my garage, I machined these parts. This is the first thing I have milled on over 40 years. While my parts are not as sexy as yours, they work amazing. I can lift the head with the hand crank with very little effort. Thanks for sharing!

This is a late response but I want to thank you for offering your services. I was fortunate to acquire a PM-30 mill that was crudely converted to CNC and I will soon try to use it to machine the adapter plates for the PM-833TV CNC conversion. If I am successful I’ll put something in this thread on how it went. Thanks again for your reply and for your extremely helpful video on converting this PM-833TV. Cheers!

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Just a head up to let you know that Arizona CNC is working on releasing a conversion kit for the PM833.

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I was just finalizing my PM833 conversion and getting ready to post the project when I ran into a problem.

I was just installing the angular contact bearings on the X and Y axis. I made sure that the thinner side of the outer race of the bearings faced out of the flange. I greased them and applied a bit of preload. I understand that I should be able to preload it to eliminate slop, but the bracket should spin freely about the ball nut. This is worked perfectly on the X-axis.

On the Y-axis even if I tighten the nut by hand to apply preload, when I spin the bracket the ball nut spins with it. I do not know why this is happening. With just a tiny preload, the ball nut spins with the bearings.

The only thing I can see is that the bearing is rubbing a bit on the rear of the Y-axis bracket. See below:

Rear side of Y-axis bracket:

Front of Y-axis bracket:

Any idea of what is happening here?

Thanks… Richard

I had what looks like a similar if not the same problem:

“The only significant problem I had with the kit was with all the screw brackets that were machined to carry the bearings. The minor bore diameter on those brackets was smaller than the major diameter of the inner bearing race. That caused the inner race to ride on the aluminum when assembled, resulting in a bunch of friction. I was able to grab the parts with the lathe and take care of that issue.”

I enlarged that bore on the lathe. See the sixth and seventh picture in my original post. On one I chucked a washer behind it to bore to to keep from crashing the tool.

Thanks Sean. After posting, I looked at your older post and realized that you had the same exact issue. I messaged you directly but am not sure if the messaging system is working. My lathe is too small to hold this bracket and my mill is still inoperable. Would you be willing to bore out my Y-axis bracket? I would be happy to pay you for your effort. You can reach me at If this is not something you are comfortable with I fully understand.

For what it is worth my entire kit was a disaster. Dr. D was kind enough to actually remake all of my other brackets as the distance between centers for the mounting screws were all incorrect. Even one of my ball nuts was defective and David Clements from Arizona CNC kits repaired the ball nut for me. For what it is worth, he is developing a conversion kit for the PM833 as we speak.

Thanks… Richard

Just a heads up. Dave Clements from Arizona CNC Kits has offered to help me out at no charge. Absolutely great guys!

I’m glad to hear you have a path to completion, and that Dave Clements is making a kit for the 833.

Anybody know if they are still in business? Their website is down indefinitely according to the message on the website.

Maintenance mode

Sorry for the inconvenience.
This website is indefinitely down.

Thank you for your understanding.

As others have said, Heavy Metal is gone but Arizona is going to be offering a kit PM-833TV and PM-932V Update - YouTube