Re: [CAD_CAM_EDM_DRO] Re: Heck of a time tuning servo motors.

3:1 is a 14 T pulley on the motor. They fit just fine on a 3/8 shaft. I have
one with a 3/8" bore that I had to sleeve to fit onto motor I am using with
a servo motor on the Shoptask.

You can not remove the lash on the spindle by just tightening the spindle
lock. The problem is in the mechanism and you have to attack it there.
Basically you need to lock the fine feed worm gear onto the shaft that
drives the spindle rack there by disabling the dog clutch that lets you use
the rapid feed. That will eliminate about 80% of your Z lash. The remainder
of what you can remove is caused by the fine feed shaft (the one the large
axis motor drive pulley goes on) moving back and forth. Best fix is to get
some needle thrust bearings and matching race washers and putting one
between the dial that has the depth gradations on it and the plate the axis
motor bolts to. The other one goes on the opposite side of the plate and the
large drive pulley. Squeeze the dial and pulley tight and lock them down
with some good screws onto the shaft. Your Z backlash should now be about
5 - 10% of what you have from the factory. Absolutely no need for more than
3:1 reduction.

Tim
[Denver, CO]
info on some of my Shoptask adventure at:
www.KTMarketing.com/CNC.html

----- Original Message -----
> Hey Dan thanks for the reply.
>
--Snip---
> The real problem with this approach is in the Z-axis (mill spindle).
> There's no easy way to loosen this up without making it useless for
> plunging/milling. I think since there is a bunch of room up there I
> am going to fashion a second stage of reduction and try to get to 4-1
> or 6-1 on my z axis giving me a ton more torque. I'm looking at
> timing belt pulleys right now. A little machining on the plate and
> an offset bearing mount and it should work.
-Snip--
>
> Addresses:
> FAQ: http://www.ktmarketing.com/faq.html
> FILES: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/files/
>
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