[Cordwood14]

Hi All, I am now working on a Cincinnati Sabre 750, Model ERH and am starting disassembly for service of the X-Axis ballscrew. X-Axis started making a loud "scratchy" sound when using rapid or high feedrates. At slower rates, say, 30 IPM, the sound has a periodic characteristic which occurs apparently at 1 point of every ballscrew revolution. This leads me to suspect that the thrust and/or support bearings are failing.

Oddly, with the way covers off, it sounds as though the sound originates from the ballscrew nut - perhaps there is conducted vibration from the bearings to the nut?

I don't feel roughness when rotating the ballscrew by hand, though there is some drag - rotating the ballscrew via the bolt at the support bearing using an allen wrench, fingers on the short end of the wrench - rotates with some difficulty.

In disassembly, how are the taper pins in the thrust bearing housing and the ball nut removed? Each has a threaded hole - would I screw in a bolt to push it out, or would I use a slide hammer? Also, how to immobilize the ballscrew when removing the bolt in the ballscrew at the far end or support bearing - clamp the removed ballscrew in a vise (with padding of course)?

Thanks,

Drew

[maver1ck]

Typical ballscrew bearing failure exhibits backlash. Before trying to pull everything apart, verify how much is present and whether it is in the bearings or nut.

Have you checked your coupling? if cracked it can exhibit odd symptoms. When checking the coupling, check the housing for evidence of coolant getting through the bearing...if the drain hole gets plugged, this will fill with coolant which then can get into the motor.

The mechanical drawing that came with the machine shows the assembly in detail so you should refer to that when tak8ng it apart....I do not remove the bearing supports (or ballscrew) when replacing the bearings.

[meckardt55]

Found out how to attach a file for your problem someone wrote this info, good luck

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