PM-833TV CNC conversion kit availability?

[7milesup]

My build is going to be $10-$11k in parts

Wow. That is 3x to 4x the amount Dave Florian has in his. I would be interested in hearing about the parts you plan on using.

 

[kirkrockwell]

Wow. That is 3x to 4x the amount Dave Florian has in his. I would be interested in hearing about the parts you plan on using.

It is about that much, I almost pooped when I tallied up the spreadsheet for my build. David's website has a bill of materials with links to parts.

Benchtop Mill CNC Conversion

Dr. D-Flo converts a manual benchtop mill, the PM-833TV, for automated machining in his garage. Learn about the mechanical and electrical systems required for this conversion.

www.drdflo.com

I followed along, adding what I absolutely needed, and discounting parts/pieces I already have. And skipped the stepper electrical parts, adding instead the AC servo electrical parts.

Starting from scratch my Precision Matthews order was $6k already for the 833TV, its stand, a 4 inch milling vise, R8 collet set, and clamp down set. That includes shipping/tax with liftgate and into shop delivery. After that I needed a $1199 conversion kit. DMM servos (z-axis with brake) total around $1100, and their drivers around $750. Power supplies and cabinet and all the small parts brought it right up there.

He makes sure to state that for this amount you could get a bare-bones Tormach. And recommends paying for a turn-key system, if you want to miss all the fun of what looks to be a 2 or 3 month build. I can only complete this type of project if I follow along with someone who has already done the legwork finding and matching parts, writing it up, and producing videos showing what it's supposed to look like when its finished. Going the DIY route lets me justify some of that dollar amount as "tuition" and "entertainment" expenses.

 

[7milesup]

It is about that much, I almost pooped when I tallied up the spreadsheet for my build. David's website has a bill of materials with links to parts.

Benchtop Mill CNC Conversion

Dr. D-Flo converts a manual benchtop mill, the PM-833TV, for automated machining in his garage. Learn about the mechanical and electrical systems required for this conversion.

www.drdflo.com

I followed along, adding what I absolutely needed, and discounting parts/pieces I already have. And skipped the stepper electrical parts, adding instead the AC servo electrical parts.

Starting from scratch my Precision Matthews order was $6k already for the 833TV, its stand, a 4 inch milling vise, R8 collet set, and clamp down set. That includes shipping/tax with liftgate and into shop delivery. After that I needed a $1199 conversion kit. DMM servos (z-axis with brake) total around $1100, and their drivers around $750. Power supplies and cabinet and all the small parts brought it right up there.

He makes sure to state that for this amount you could get a bare-bones Tormach. And recommends paying for a turn-key system, if you want to miss all the fun of what looks to be a 2 or 3 month build. I can only complete this type of project if I follow along with someone who has already done the legwork finding and matching parts, writing it up, and producing videos showing what it's supposed to look like when its finished. Going the DIY route lets me justify some of that dollar amount as "tuition" and "entertainment" expenses.

Ahhhh. That makes more sense now that you are including the mill and all of its accouterments. I already have the mill, which I have been using for a few years now.
I did consider going the Tormach route but my understanding is that there is no manual mode. I would like the option of turning a handwheel should I have the need.

 

[kirkrockwell]

Ahhhh. That makes more sense now that you are including the mill and all of its accouterments. I already have the mill, which I have been using for a few years now.
I did consider going the Tormach route but my understanding is that there is no manual mode. I would like the option of turning a handwheel should I have the need.

When I built my Sherline I sourced steppers with dual shaft to continue using the handwheels. I rarely did, but instead used my MPG to work manually.

 

[Crazy Cat]

A lot of the work involves machining the mounts to fit your motors, and opening up the base and table to accommodate the ballnuts and couplings, machining the oil grooves and tapping out the fitting holes. I needed a lathe for the ball screw ends because my motors have 16mm shafts, and one of the screws was an inch short. If you just bolt everything up, you just run into problems with the existing holes being slightly off and miss-alignment problems. The base required quite a bit of grinding and sawzall work to accommodate the y axis screw and nut.

I bought my servos and drives off of ebay for a fraction of what they would cost new, but then there is a lot of messing with them to get them configured correctly, and the cost of cables and connectors. Right now I'm putting the control cabinet together, and there is the cost of the power supplies, contactors, breakers, din rails, filters, switches, limit switches, wiring, the cabinet, oil lines, pump, relays, etc....

To do it correctly it is quite a bit of work, and money, and its rewarding and fun as well. Just be prepared for all of the incidental work and costs.

 

[7milesup]

When I built my Sherline I sourced steppers with dual shaft to continue using the handwheels. I rarely did, but instead used my MPG to work manually.

I am assuming that the handwheels felt "coggy?" From my understanding the larger the stepper motor the more pronounced the cogging effect. I wonder how that would play out on this mill because the steppers will be considerably larger than on the Sherline. Servos would not have that effect when powered off, is that correct?

 

[kirkrockwell]

I am assuming that the handwheels felt "coggy?" From my understanding the larger the stepper motor the more pronounced the cogging effect. I wonder how that would play out on this mill because the steppers will be considerably larger than on the Sherline. Servos would not have that effect when powered off, is that correct?

Yes, the cogging was noticable even on the nema 24 steppers. Also when spinning the handwheel faster, the stepper would generate power and illuminate the lights on the driver even with everything turned off. That could be stopped by disconnecting the stepper leads.

As I understand the AC servos are free to spin when unpowered. That's why the z-axis servo needs to have a brake that applies when power is off, or the weight of the whole axis can cause the head to ride down the ball screw and impact the table/vise.

 

[arizonavideo]

Hi Dave,
I bet you'll catch a bunch of us guys trying to do the PM-833T/V models! I am self taught / novice level at CNC. I started by building out a Sherline 5800 CNC ready desktop mill. Now that it's gone, I intend to use the PM-833TV build as both a continuation of the learning, and in support of my other hobbies and interests.

My build is going to be $10-$11k in parts and the CNC conversion kit from Bruce would be $1200 of that amount. My expectations are in-line with "hobby level" accuracy. My preference would be what looks like your standard 940 kit, that has the C7 ballscrews with double nuts set up to avoid backlash, and including the angular contact bearings. I intend to follow David Florians example, including the DMM servo upgrades. I think the X and Y were nema 34 with 1/2 inch shafts and a Z-axis nema 42 with 5/8 inch shaft. A couple hundred bucks either way isn't going to stop me from doing this.

I read Davids build list and its fine but you can make changes.

The DMM 86N is just fine for all axes. It is a 750 watt servo and most the time you will be milling with 60 watts of power on the X and Y. The only question is the Z and a break. The 86N has been used lots for the PM-940 with no break. If you have medium preload on the AC bearing and snug gibs the head wont drop. The larger 32mm Z screw also has a bit more friction. On my 940 the head does not drop but with the power off and if I hammer on the vise and vibrate the mill it will go down some. I still have a 25mm screw.

I still like some of the closed loop steppers, mostly the Stepper Online drivers are good. 1200 oz for the X and Y and 1600 for the Z.

If you guys want to measure up the parts for me I can make them. We can do it here if you want.

The strange thing here is my best friend from grade school and for many years after was named Bruce Nelson. He had heart problems and died 4 years ago. Still miss hims sometimes....
Thanks
Dave

 

[kirkrockwell]

I read Davids build list and its fine but you can make changes.

The DMM 86N is just fine for all axes. It is a 750 watt servo and most the time you will be milling with 60 watts of power on the X and Y. The only question is the Z and a break. The 86N has been used lots for the PM-940 with no break. If you have medium preload on the AC bearing and snug gibs the head wont drop. The larger 32mm Z screw also has a bit more friction. On my 940 the head does not drop but with the power off and if I hammer on the vise and vibrate the mill it will go down some. I still have a 25mm screw.

I still like some of the closed loop steppers, mostly the Stepper Online drivers are good. 1200 oz for the X and Y and 1600 for the Z.

If you guys want to measure up the parts for me I can make them. We can do it here if you want.

The strange thing here is my best friend from grade school and for many years after was named Bruce Nelson. He had heart problems and died 4 years ago. Still miss hims sometimes....
Thanks
Dave

Good to know about the z-axis, that 940 is a heavier machine. I used Stepper Online before, and on this build I want to use the upgrades, keeping in line with the 'more premium' nature of the PM-833VT. But if I don't need that 1300 watt braked motor it would save a chunk, thanks for the practical advise.

I emailed you about my situation. The mill is in my shop waiting to be torn into.

 

[BrokenSpoke]

Is there a final verdict on this? I was literally ready to buy the conversion kit based on the DFlo video (bought the mill a year ago - waiting to save up enough spare cash for CNC)... but, apparently the company that made the conversion kit is gone? Any other conversion kits for the 833TV? Or at least some drawings/parts list I can purchase?