Re: [CAD_CAM_EDM_DRO] Z-Axis backlash removal

Your post doesn't say what size your mill drill is or what model.
Most mill drills seem to come stock with .020" backlash. Most of the problem is due to the machining of the bores for the cross shaft and pinion. They machine the bore so that the pinion is loose against the rack on the quill. The other problem is the worn wheel housing is properly adjusted so that the worm contacts the worm wheel properly.
There are a couple solutions.
One is to counterbalance the quill so that the backlash is always up. The other method is to replace the existing cross shaft flanged bearing with a new one that is made excentric. This would also require the machining of the shaft on the worm wheel side so that there are two eccentric bearings holding the cross shaft. These are then roated until the backlash is gone. If you want I have a detailed explaination of this procedure. Give me your email address and I'll send it to you am also woking on an air spring that has a constant 40 lb lift of the quill. I have one in my mill drill but I haven't had time to to much testing
Dan Mauch
economical 3D scanner software and kits
low cost stepper and servo motors.
cases for Gecko drives
kits and assembled 3-4 axis drives
www.camtronics-cnc.com
www.seanet.com/~dmauch

----- Original Message -----
From: Dave Sage
To: CAD_CAM_EDM_DRO@yahoogroups.com
Sent: Tuesday, June 03, 2008 5:04 PM
Subject: [CAD_CAM_EDM_DRO] Z-Axis backlash removal


Hi:

This is my first post here. I've been sitting in the bushes trying to gather
as much info as possible.

I'm in the process of converting my mill/drill to CNC. I have ball screws
ordered for the X and Y and motors and drives ready to go for all 3 axis.
I'm wondering what to do to remove the backlash (about 15thou) from the
Z-axis. If anyone has any suggestions what is typically done I'd appreciate
it and I'd follow that lead.

Sage

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