Something Old, Something New..Upgrading An Old CNC Millrite

[Karl_T]

Hey TMT,

Same guy as on RCM?


You certainly want to go Mach with steppers. Gecko should have dirves you need. As Al said, VFD to drive your spindle.

Karl

[cjmerlincnc]

Hi, I've not seen one. It would be great for others if you post some pics as you are doing the retro-fit. When I was looking for my mill (Ebay!!) the problem I had was you only see Bridgeports (too big for a small machineshop/garage/shed) or benchtop mills which are ok for hobby use but maybe not for manufacturing parts everyday. The other problem was that Bridgeports come up cheap on Ebay and hobby mills tend to go for high rediculous prices, lucky for me I got a 3/4 sized knee mill + tooling which was only a few months old for about a third of the price from new.
Now the long slog to find the time between work and converting it to CNC.

Can't wait...

Good luck with your project.

[Cyclotronguy]

Just a personal opine. I've rebuilt a couple of the Millrite / Powermatic vertical mills. Like the spindle's with their tapered Timken bearings.. they are really nice.

Hate the gibs on the saddle and table. They are not tapered and are difficult to adjust just right. The crossfeed screw sets outside the ways, given any play in the saddle gibs the saddle fishtails it's way across the knee.

The crossfeed screw (0.200 inch / Rev) does have a backlash adjustment via split nut, if the long axis on yours also has backlash adjustment then you may be able to keep the acme screws.

Cyclotronguy

[hybidder]

Well since you asked,

Leave the acme screws for now, hold off on the VFD. I have seen several posts mentioning interference from VFDs with breakout boards and drivers- I didn't say ALL but some. Leave the screws as they are, you can always upgrade later to ballscrews if you're seriously in trouble accuracy-wise. I'm a firm believer in taking things one step at a time instead of trying to throw everything including the kitchen sink into a retro. Get the basics down pat and operating reliably then add the bells and whistles later- one at a time.

If your motors spec's match up, get the Gecko 203v drives and a good breakout board. I'm using three 203v's and a CNC4PC C11 breakout board running Mach3 on my converted Bridgeport II copy and they work flawlessly together. I kept my old CNC controller but use it only as a DRO and comparing the Mach3 output position to the actual position on the DRO my 20+ yearold machine (with original ballscrews) will usually hold .001" and often better.

[voltsandbolts]

How did your Millrite turn out?