Re: [CAD_CAM_EDM_DRO] Ball screw adjustment?

Allan;
I went through this same exercise and determined it was easier to get paired
nuts from Rockford Ballscrew. My 3/4" preload nuts were $271 each.

Lead error is both additive and periodic. I think the .004/ft claim is
somewhat misleading. You can easily compensate for consistant lead error.
Thread drunkenness (periodic error with a period of one turn) cannot easily
be compensated for, and this is the type of error you may find in rolled
thread screws. We found this to be a problem on a machine we just finished.

Doug

----- Original Message -----
From: <allan_r9@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Monday, November 05, 2001 4:11 PM
Subject: [CAD_CAM_EDM_DRO] Ball screw adjustment?


> Hello Group,
>
> Has anybody on this list tried to "make" a preloaded ball nut from
> two standard nuts spaced apart? Is this a practical idea for use on
> McMaster ballscrews with a lead error tolerance of 0.004"/ft.? I
> talked to Rockford Ball Screws and found the price of the 3/4"
> preloaded nut was ~6X the price for 2 McMaster regular ball nuts.
> When "lead error" is quoted, is the error a linear additive, or
> variable amount? Restated, is the 0.004"/ft error consistent on the
> next 12", or is it some other distance on the next 12"?
> I'm getting ready to order the 3 screws for the GEM 500 machine, so
> looking for feedback. The 3D model will be placed on the Files list
> soon, along with the 5 axis trunnion table.
>
> Thanks in advance,
> Allan
>
>
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