[comtech]

I bought a PM-30MV machine used it and decided it needed a DRO or for around the same price a CNC conversion. I chose the CNC conversion, more so just to see if I could do it.

I have ripped my machine down and cataloged all the parts and am ready to start upgrading the machine. I ordered the DVD from HossMachine to give me a base line on the stuff I need, since i have never attempted something like this before, the fabricating of the parts is no big deal, I'm worried about ordering the right parts, electronics and ball screws.

Right now I am stuck looking for answers on the Bearings and ball screws. My PM has larger bearings than the G0704 so I found the same type just different sizes larger,(12x28x8-x/y)and(17X35X10-z), but the ball screws have me worried.

Should i go with the HOSS recommend screws or go larger, match the size in the machine, or go with HOSS recommendation. Will it make a difference? Anyone know?

[comtech]

Z Question - Should I keep the Hydraulic cylinder inside the Z column or eliminate it altogether? Will the Stepper motor have the power. (going to use hoss super digital package).

[arizonavideo]

Hoss's DVD is for the PM-20 size machine so you can only use it as a guide as all the parts are larger on the PM-30.

You should leave the air spring on yours if it has one.

You should have enough room under the table to use a 5/8" Roton ball nut without matching the Y slide.

I have a Weiss 30 but have not CNC it yet.

[comtech]

Ok that settles it I will go the the 5/8 ball screw and just machine it to the specs for the G0704. Other than being a bit larger / heavier I don't think that there is much difference in the machines. I don't much worry about modifying the parts to suit my needs I just don't want to throw money away needlessly on electronics or parts so Im going to do as much research and ask as many questions as I can and hope people will give input. I thank you arizonavideo for you thoughts and am going to move forward on ordering parts.

[arizonavideo]

I have both a 30 and a 20 and they look the same but everything is larger on the 30. 280# V 500#

The same motors and screws will be fine but the head is heavier so you will get lower speeds but that should also work OK.

If you decide to go with a belt drive for the Z I made a nice motor mount and bearing mount and I could throw in a ball screw and AC bearings.

Send me a PM if you wish

[comtech]

I actually found out last night after going over bearing sizes I can't use the 5/8" there is not enough material for the bearing I had to use so I just purchased 85 inches of 3/4" x .200 rotor ball screw and nuts. The machine has 3/4" screws to start with. Thanks for the offer on the motor mount but I want to make my own, figuring this stuff out is the best part of the project. Since Otis just a hobby I can experiment a bit, and it doesn't matter if the machine is down or not I have a back up manual machine.

I am going to order the bearings, shims, couplers and oversized balls tonight. Soon I'll be able to grind down the screws to the right size.

[arizonavideo]

I just remembered that the mount is for the G0704 and not the 30. I should know this it took days to do the mount...

[LUCKY13]

Thats a very good looking mount there arizonavideo. IDk I really like it when a design has some curves to it. I always felt like the designers back in the day (40's-50's) did things like that for safty so people where not getting hurt on the edges of machine parts. SOme people claim it was just a part of the times but I always felt like there was more to than that. ANyway great design, and very compact to.


Jess

[hoss2006]

Kirby, are my emails getting thru?
I responded to a few of them but noticed you're not replying back but using one of my different accounts to send a new one.
I'm not ignoring you, check your spam folder, I get that occasionally when sending to a new address the first time.
Hoss

[Mad Welder]

..... I want to make my own, figuring this stuff out is the best part of the project.......

Welcome comtech and brilliant another new build in progress.....post loads of pics for those of us (me) who prefer photos instead of reading and yup I agree the figuring and the making is the best part too.......and you can always make temporary motor mounts and machine nicer mounts and brackets when it's together.....

[comtech]

For my PM-30MV conversion I purchased the following...using Hoss Plans as a guide...
VXB - Angle Thrust Bearings 5 − 12X28X8 for the x and Y and 2 17X35X10
3/4 X .2 Roton Ball screw and nuts for all 3 Axis (54" Total)
300 - Oversized Ball Bearings.1265.
1 1 1/8 − 18 Tap
Im into this about $350 thus far.

Working on the Z axis part first. I have made a new Z ball screw mount out of bar stock and threaded it for the ball nut. Repacked all the ball nuts with oversized balls (No back lash now). I went the cheap route and made my own shims for the bearings, the bearings didn't quite fit into the stock holes so I just made a round shim pushed it into the z axis plate and am in business. If any interest i can post pix

[comtech]

New Z Ball Nut Mount for a PM-30MV. Used the original mount for the head with 2 set screws and then made the new ball screw mount to fit into the original part. The ball nut swivels in the mount just like the original. I also added a stainless steel set screw and a piece of copper in the set screw hole to lock the ball nut in place. THe copper keeps the set screw from crushing the threads of the ball nut. I'm not sure this setup is going to work but Im going to give it a shot.

[comtech]

Well I didn't want to spend the money on shims for the z bearings so I just made some. Now the angular bearings are centered, work and fit properly.

[Mad Welder]

Very nice.....

[comtech]

The z axis is finished, ball nuts repacked, bushings installed, and bearing dust cover is made. I had to push on a bushing with a flange on the z axis and lock it on with lock tight because I was afraid that there wasn't enough of a lip for the lower bearing to rest. The lock nut is 1/2-20, end of the screw is turned down to .3750 for an oldham coupler. Here are a few pictures of the Z assembly minus the stepper motor mount haven't made that yet......

[comtech]

[comtech]

Motor mounts, thrust bearings, z limit switchfigured I'd just use existing lock for limit switch activator.

[comtech]

Just purchased kit from cnc4pc. I ordered Cs4sa4-1 cn. Stepper motor control box kit, x3 motor kit, limit switches, touch probe, pendant from Arturo Duncan.

Waking on some pieces parts and an update on instructions but you can see what I have.....

[aaron2496]

Hey Comtech,

Your X ball mount here looks like it's bolted right into the stock location. Did you have to machine out any material from the saddle to fit this in?

[comtech]

It is bolted in the stock location, I had to make a small pocket to accommodate the ball nut.