Bridgeport R2E4 - Unacceptable Backlash in X axis

I've discovered that my Bridgeport R2E4 has 3-5 thou backlash in the X axis.

The Y axis also had some backlash (3 thou), but after tightening the gibs, it is down to 1 thou.

Tightening the gibs on the X axis made the X backlash worse - 3 thou backlash before tightening, 5 thou after tightening). The motor is spinning, as is the nut, but no travel for those few thou. Is there a way to tighten the nut some how? I found nothing in the maintenance manual talking about adjusting the ball screws (if that is even possible).


Anyone have any ideas? Or is the machine just wore out?

Thanks!

You need to switch from using way oil to using a mixture of STP and sawdust. A better alternative is to have the screws rebuilt.
No, there's no adjustment. 3-5 thou after 30+ years is pretty typical for a r2c4. You could repack the ball screws yourself and improve things tremendously, but you need to know what you're doing.

Check the backlash in several locations. Near the ends where the ball a few is not used as much. You could also put a indicator on the table and ball screw and try to push the unit and see what is .moving. the ball screw bearing may need to be tightened a bit. Otherwise the screw nut assembly is bad. Righting the fibs will make it worse as more pressure is needed. Got to go...rich

Thank you, Larry and Richard, for the replies.

I was afraid someone would say the ball screw assemblies needed to be rebuilt. Perhaps down the road. I will definitely check the table for backlash in different locations. I'm not sure why I didn't do that at the time. Rich, how would I check the bearing? On this machine, the screw is stationary, and the nut moves. I'll be 100% honest - I have very little idea of what exactly is going on under the table on this thing. The parts diagram doesn't make it clear what is what, as it simply calls the entire ball assembly by part number.

I don't need this machine to be the most precision thing in the world, but I would like to get some good parts off it. After checking backlash at multiple locations on the table, I may try setting backlash compensation, and see if that gets me a little closer.