Re: [CAD_CAM_EDM_DRO] Threads on a ball screw........

Will,
 
There are various types of sleeve retaining compounds, shaft compounds , etc.    I don't know what they are but they seem to expand between a sleeve and a shaft and glue the two together.    The stuff I am using is from the auto store but I have also used Loctite products made for larger gaps up to .030" and they work.   On my mill ball screw it seems to be working just fine so far.
 
My lathe is a chinese hunk of junque but it works for 95% of what I need it for.  It is not rigid enough for this type of turning on hard steel.   Given a good tight rigid lathe and proper tooling there is no reason why the end of a ball screw can't be turned.  Grinding shouldn't be required but of course can be done.
 
jack

--- On Tue, 2/23/10, Will Holding <76lancia@...> wrote:


From: Will Holding <76lancia@...>
Subject: Re: [CAD_CAM_EDM_DRO] Threads on a ball screw........
To: CAD_CAM_EDM_DRO@yahoogroups.com
Date: Tuesday, February 23, 2010, 4:33 PM


 



What is this "sleeve goop" you speak of, something better than threadlocker?

Those ballscrews ARE nearly impossible to cut down or thread, makes a good case for making yourself an inexpensive toolpost grinder. You just have to cover your entire machine with plastic so you don't get the grinding mess into your ways.

-Will

----- Original Message -----
From: Jack McKie
To: CAD_CAM_EDM_ DRO@yahoogroups. com
Sent: Tuesday, February 23, 2010 3:59 PM
Subject: Re: [CAD_CAM_EDM_ DRO] Threads on a ball screw....... .

David,

Yes, an interference fit would work but the nice thing about the goop is that the part can be removed easily if need be. Another issue is that this ball screw was a bugger to machine, even with carbide tool so the surface isn't all that great. I have machined "press fits" in steel and iron that were pretty tight with about .0005-.001" interference but they are tricky. The goop is supposed to hold about 3000psi in shear. Machining these ball screws isn't fun and at least for me, this is a simple solution.

Jack

--- On Tue, 2/23/10, David G. LeVine <dlevine@speakeasy. net> wrote:

From: David G. LeVine <dlevine@speakeasy. net>
Subject: Re: [CAD_CAM_EDM_ DRO] Threads on a ball screw....... .
To: CAD_CAM_EDM_ DRO@yahoogroups. com
Date: Tuesday, February 23, 2010, 2:26 PM

Jack wrote:
>
>
>
> I have converted my minimill to ball screws but was having problems with
> shaft collars shifting causing backlash. The solution was to fit a nut
> to lock the collar in place. I had trouble with both my lathe and the
> hard material in turning the thread and spoiled the thread. The
> solution was to turn down the shaft in that area. Drill out and cut off
> a bolt to form a threaded sleeve. The sleeve is attached with sleeve
> retaining goop. Assuming the goop holds the sleeve this is a simple
> way to put threads on the ball screw and I plan on using the method in
> the future since it was quick and simple. I thought this might be of
> use to someone in the group.
>
> Jack
>

Actually, if you can machine closely enough, heating the threaded part
and cooling the ball screw will allow you to press the screw onto the
shaft. Shrink fits (like the one described) are VERY secure, they must
be machined off to remove them! And, no, I don't know what the
interference fit would have to be, but given the dimensions it should be
pretty easy to find out.

--
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12 Clairmoor Drive
Nashua, NH 03060

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