7/16"-20 tpi X Slide Leadscrew Mod   

 

 
    After seeing all the discussion about the error in the cross slide & being disgusted with the adjustments or lack thereof, I decided to start thinking about how I could fix some of the problems I have encountered:

#1 - There is alot of endplay in the metric leadscrew. This causes around 10 thousandths backlash minimum in my cross slide. I have placed brass washers between the leadscrew & mount, grad dial and mount, but still have some play.

#2 - A metric leadscrew is not an acurate way of moving the leadscrew in divisions of an inch. Therefore a leadscrew with imperial threading is desirable. I chose 20 TPI, as this only requires 50 divisions, and I just happen to have a 50 tooth change gear for the 7x10. The Sherline leadscrews on my mill are 1/4-20 and it uses a 50 division resetable collar which I find a joy to use. So I decided to mak my own leadscrew in 7/16-20. I had a piece of 5/8" 12L14 a couple feet long so I used that. I also had to adjust the TAILSTOCK becaused that turned out to be about .020" off. I was having a devil of a time trying to get the threaded are turned down to an even dimension. So I spent time fixing the tailstock so that I was not turning tapers anymore.

After finishing I have found that I now have no trouble turning to a specific diameter. I used to have to take a cut, measure, take a cut, measure, on and on and on... Now I measure take a cut to bring me to an even .010" boundry. Then crang in to take a .020" cut, cut again, measure when I should be about .020" from my target dia. take a .010" cut, then a couple .005" cuts & I'm there with a beautiful finish. I probably should be more careful but this works EVERY time for me, YMMV.

Drawing of all parts
Parts Dwg [PNG Format](67k)
ls-modp-2.png
Assy Drawing [PNG Format](34k)
Drawing of all parts
Parts Dwg [GIF Format] BIG!!(215k)
Assembly Drawing
Assy Drawing GIF Format BIG!!(139k)


Last updated 04/17/2001



All above images Copyright (c)2000
Ty Hoeffer


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For more information email me at:
pth3k@virginia.edu