PM-833TV CNC conversion kit availability?

When I was on the site I made sure to download the PM-833TV installation instructions. After my order went through, and my credit card was charged, I went outside to move a bunch of snow.

I just came back in and saw 2 emails from HMCNC. First one was an (I assume automated) confirmation of my order stating that it was being processed. The second one was from Bruces email address stating "WE ARE CLOSED . NOT DOING BUSINESS"

The link you showed me to Automated Technologies Inc. has what looks like the base model (non-premium ballscrews) kit. It allows me to put the kit in the cart, but I didn't go any further. My impression is that they are reps for HMCNC, not making their own kits.

Thanks for the offer, how close are you to installing your parts? Close-up pics combined with some measurements I could take might be helpful. Any mounts I could improvise would be pretty crude, I have no way to mill circular pockets or holes for bearings.
 
kirkrockwell said:
Hi Matt,
I am in that situation, purchased the PM-833TV with intentions to convert for CNC use. I ordered it in early January, and it is supposed to be delivered this Friday. I had several calls into Bruce's phone number, and didn't understand why I couldn't get a call back. I found out here about the bad news. I suppose they still have the kits in stock, and are hopefully re-grouping to keep going. But I also imagine the recovery will take time, nothing generates more grief and paperwork than an unexpected death...

I'm really hoping to salvage this project, do you have contact info for Jose, if it's ok to ask?

I have also contacted David at Arizona CNC Kits, asking if maybe one of his kits would crossover. He seems willing to work with me if I can get measurements to him for comparison. When it gets to my shop I'll see what I can find out. I don't have any experience with the other benchtop models so I don't have any clue what is the same or different between them. If anyone has the experience I'd welcome the help.

I got hooked on CNC when I worked for a shop that had a Tormach 1100 for production use. To train myself, I bought and converted one of the Sherline 5800 desktop units for CNC, using steppers, Gecko drivers, and Centroid Acorn. I learned Fusion 360 Design and Manufacturing modules and sucessfully made a lot of small parts. The PM-833TV really looked like a nice step-up option so I worked up a list of stuff to buy following the online example by Dr. D-Flo.
Click to expand...
Are you going the Linux route?
 
I have experience with Centroid Acorn, and want to go with that to reduce the learning curve for this build. I have never setup Linux before and already have a windows laptop with Acorn that was dedicated to my old Sherline setup.
 
kirkrockwell said:
I have experience with Centroid Acorn, and want to go with that to reduce the learning curve for this build. I have never setup Linux before and already have a windows laptop with Acorn that was dedicated to my old Sherline setup.
Click to expand...
Sounds like a good plan. I need to move forward on this project but work keeps getting in the way of stuff I really want to do!
 
Do you already have a CNC conversion kit? That may be the limiting factor for a while. I'll post here if the one I ordered today for the 833TV gets shipped to me. If not it's going to be a slower process, I'll still have a nice manual mill to work on though. David at Arizona CNC Kits said they are working on a kit for the PM 932V which is a RF45 clone. Is my PM-833TV an RF45 clone also?
 
I have the Arizona CNC kit on my PM-940. Dave does nice work and is great to deal with. If he will make a kit for the PM-833, I am sure you will be happy with it.
 
It's pretty puzzling that they would resurrect the website and then claim they are "not doing business" the instant an order has been placed. Their advertised shipping time was 3 business days if I remember correctly. I would give them a few days and contact my CC. It did the trick for me (I used PP though) - if they still have inventory, it might work for you too.

I looked at the kit and can't see why one wouldn't be able to make its functional equivalent on a manual mill. The bearing pockets could be machined on a rotary table. The Z-axis attachment is probably the trickiest part, but should still be doable. The big problem is sourcing the ball screws at a reasonable price. Then, one needs access to a lathe to turn the screws to accept the couplers/pulley.

The rest of the kit is not particularly impressive, which is hardly surprising at that price. The bearings are of rollerblade quality - I know it is a contentious topic, but I'm replacing mine, which will cost me another ~$300 for 3 pairs of midrange 7002 angular contact bearings. Same story with the couplers - they have to go. What worries me is the condition of the ball screws - in addition to corrosion, they are marred all over the place. Nothing major, but it may affect the durability of the ball nuts. Since it is definitely not shipping damage, they were either mishandled or Heavy Metal had bought somebody's surplus/NOS.

I can't be sure, but just looking at the pictures of the PM-932V it seems sufficiently different from my 833, I doubt the kit is going to work.

I may end up going with LinuxCNC, but I will first try grblHAL:

Grbl

www.grbl.org www.grbl.org
github.com

grblHAL

grblHAL has 45 repositories available. Follow their code on GitHub.
github.com github.com

I bought a breakout board from:

www.tindie.com

grblHAL BoB Unkit for Teensy 4.1. - T41U5XBB by Brookwood Design on Tindie

Breakout Board for a Teensy 4.1 to run grblHAL for controlling CNC routers, etc.
www.tindie.com www.tindie.com

put it together, compiled grblHAL for it, hooked up some old steppers, and it seems to work very well. I still haven't figured out how to handle the MPG part of it, which may turn out to be a deal breaker for me. I'll decide when I get there - for now, I have to install the kit and buy servos etc.




​

 
kirkrockwell said:
Do you already have a CNC conversion kit? That may be the limiting factor for a while. I'll post here if the one I ordered today for the 833TV gets shipped to me. If not it's going to be a slower process, I'll still have a nice manual mill to work on though. David at Arizona CNC Kits said they are working on a kit for the PM 932V which is a RF45 clone. Is my PM-833TV an RF45 clone also?
Click to expand...
The 833 may very well be an RF45 clone also. I just looked at the PM website and the 932 looks to be made in China vs the 833 that comes out of Taiwan.
I do not have a conversion kit. Converting my 833T to CNC has been on my to-do list for quite some time, I just don't seem to ever have the time. The mounting blocks and other parts of it can be made in your shop on the 833. It may be somewhat of a slow process because of the need to disassemble the mill to take measurements and then reassemble it to make parts. I have a 1440 lathe, so re-working the ends of a ball screw would not be a problem.
Speaking of ball screws, there are many suppliers of ball screws. I have heard of decent ball screws coming out of China (AliExpress) and other discount areas.
https://www.roton.com/ is a source I have considered.
https://www.vxb.com/Ballscrews-s/369.htm
https://www.automation4less.com/ballscrews.htm
https://www.cnczone.com/forums/benc...ball-screws-quality-choice-mapping-buy-7.html (not sure if I can link to an outside forum).
Ball screws come in two flavors, ground and rolled. For most of us, rolled ball screws are most likely adequate. Ground ball screws are exceedingly cost prohibitive.
 
The premium Heavy Metal kit comes with ground ball screws and it's only $200 more than the standard one with rolled screws.
 
BehemothTheCat said:
It's pretty puzzling that they would resurrect the website and then claim they are "not doing business" the instant an order has been placed. Their advertised shipping time was 3 business days if I remember correctly. I would give them a few days and contact my CC. It did the trick for me (I used PP though) - if they still have inventory, it might work for you too.

I looked at the kit and can't see why one wouldn't be able to make its functional equivalent on a manual mill. The bearing pockets could be machined on a rotary table. The Z-axis attachment is probably the trickiest part, but should still be doable. The big problem is sourcing the ball screws at a reasonable price. Then, one needs access to a lathe to turn the screws to accept the couplers/pulley.

The rest of the kit is not particularly impressive, which is hardly surprising at that price. The bearings are of rollerblade quality - I know it is a contentious topic, but I'm replacing mine, which will cost me another ~$300 for 3 pairs of midrange 7002 angular contact bearings. Same story with the couplers - they have to go. What worries me is the condition of the ball screws - in addition to corrosion, they are marred all over the place. Nothing major, but it may affect the durability of the ball nuts. Since it is definitely not shipping damage, they were either mishandled or Heavy Metal had bought somebody's surplus/NOS.

I can't be sure, but just looking at the pictures of the PM-932V it seems sufficiently different from my 833, I doubt the kit is going to work.

I may end up going with LinuxCNC, but I will first try grblHAL:

Grbl

www.grbl.org www.grbl.org
github.com

grblHAL

grblHAL has 45 repositories available. Follow their code on GitHub.
github.com github.com

I bought a breakout board from:

www.tindie.com

grblHAL BoB Unkit for Teensy 4.1. - T41U5XBB by Brookwood Design on Tindie

Breakout Board for a Teensy 4.1 to run grblHAL for controlling CNC routers, etc.
www.tindie.com www.tindie.com

put it together, compiled grblHAL for it, hooked up some old steppers, and it seems to work very well. I still haven't figured out how to handle the MPG part of it, which may turn out to be a deal breaker for me. I'll decide when I get there - for now, I have to install the kit and buy servos etc.




​

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