Reply with QuoteIt does sound like a backlash issue. The normal causes are: 1) loose motor coupling, 2) thrust bearing adjustment, 3) worn ball nut/screw.
.007" egg-shaped holes while circle-milling
I'm getting about .007" egg-shaped holes while trying to circle mill.
It appears to be happening in the X Axis.
Does this sound like a backlash issue, and what needs adjusting?
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Re: .007" egg-shaped holes while circle-milling
It does sound like a backlash issue. The normal causes are: 1) loose motor coupling, 2) thrust bearing adjustment, 3) worn ball nut/screw.
Jim Dawson
Sandy, Oregon, USA
Re: .007" egg-shaped holes while circle-milling
0.007" that's like 0.17 ish in mm. That's a lot for it to be a backlash problem alone.
Sounds like something is loose or needs a lot of adjustment.
Re: .007" egg-shaped holes while circle-milling
Which axis has the correct size for the diameter ? .... that is the axis that doesn't have a problem.
Are there flats where the axis changes direction ?
As Daz says, check all items that are on that axis, I've seen bodgy work where some builder used pointed set screws instead of keys on drive mechanisms.
Re: .007" egg-shaped holes while circle-milling
Y axis is correct, X axis is over-sized .007".
I'm guessing it's the Thrust-Bearings.
Re: .007" egg-shaped holes while circle-milling
Not on a Tormach, but the last time I had an issue like this the ballnut was loose in the carriage. Easy fix.
Check the play between the ball nut halves in the X axis. They have a spacer between them to preload them. Put in enough shim to take out the slop.Originally Posted by RussMachine
Re: .007" egg-shaped holes while circle-milling
I did this on my Y axis ball nut,it worked well. I am thinking offset keys that hold the two halves together, then a spacer shim wouldnt be needed, I just have to get up the "want to" to get it done.The parts I make arent that critical.
mike sr
