Quote Originally Posted by Muzzer View Post
I dunno about komatias but I got mine from AliExpress, machined to my own drawings for a nominal cost, like $5 per ballscrew - that saved a lot of messing about and they did a good job. The std ballnut diameter is slightly bigger than the std leadscrew nut, so I machined my yoke out on the (Bantam) lathe. Unless your machine is in almost new condition, you may struggle to justify expensive ballscrews, as there will be slop and backlash even once the gibs are adjusted. The ballscrews account for only a part of the total.

Using an MPG means I don't need the X & Y handwheels, which (in my case) added a lot of unhelpful moment of inertia to the servos so I removed them and have a better servo response. I still have the original DRO I fitted years ago but this simply tells me how worn the machine is. If you can achieve backlash below 20-30um (0.001"), I'd say you are doing well. However, the actual accuracy will be worse when you are machining as opposed to cutting air, as there will be additional forces at play - but the willy wavers tend not to get into measuring that, as it spoils the fun.
Thanks for the info I have already converted my Series 1 to CNC using the standard acme screws and also removed the handles 'cos I was getting fed up with getting the occasional thump. By the way I'm with you on appropriate accuracy for outlay I paid £130 for my Bridgeport as it literally had fallen off a lorry and the head casting was cracked. Another £150 in used spares got me going and I've spent another £700 on the CNC conversion. So value.

One thing that puzzles me is the wall thickness on the standard Bridgeport yolk. I can see there is enough meat to machine out from 32mm to 40 mm but there does not appear to be enough wall thickness for the securing bolts without breaking through the wall. How did you manage?

I guess I could buy a 2505 ballnut and dismantle the X axis to see better but I'm pushed for time as we are moving house in the spring so any info would be highly appreciated.

Cheers
David