Re: backlash fixes etc.


gorvil
 

Hi All,

This backlash thread (pun intended) has been very interesing to me.
There are lots of good ideas and great suggestions. I am in the
middle of fixing my cross slide to reduce backlash, so this is very
timely.

Small Parts Inc. sells lead screws and anti-baclash nuts that appear
from the catalog photo to be of the spring loaded double nut type
mentioned earlier in this thread. I am not suggesting that anyone
should go out and buy from them, but the photo makes it easy to see
how the system works. They have an online catalog at
www.smallparts.com.

Micro-Mark sells low temperature alloys of various types for
casting. They sell tools and supplies for the model railroaders (I
mean HO not 1/7 scale live steamers) so you can get small amounts
(11.4 oz.) for under $15.00.

I made a new nut for my cross slide last night. This was the third
try but the learning process is part of the reason for doing this in
the first place. I made a simple threading tool to cut the threads.
I turned down a 3" x 1/2" round bar to under a 1/4" on 2/3 of it's
length. I drilled and tapped a 6-32 set screw in the small end of
the bar and about 1/2" from the end I drilled a 3/32" hole through
the diameter of the bar. A piece of 3/32" drill rod ground slightly
under sized to the thread on my cross slide made the cutting tool.
It helps to grind a flat on the side of the drill rod with a slight
bevel against the set screw to help hold it in place. The 1/2" end
of the bar mounts up in my boring bar holder. You can replace the
cutter as often as needed to finish the job or regrind it to change
the profile of the cut. I think a tool of this sort is called a
broaching bar when you use it to make keyways or rifleing.

I found that my new nut fits very tightly on the end of the screw
where there is less wear and fairly loosely in the center part of the
screw where most of the action has been. I have some Delrin rod
stock, so I may try the spring loaded anti-backlash double nut system.

I'll post the results when I'm done.

Glen Reeser

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