Re: Sherline Z-axis ballscrew feed.

Tim:

I'm thinking along the lines of a T-nut with a pre-loaded compression
spring against the saddle nut. The arms of the 'T' would ride
against the back of the mill column (or bottom of the lathe bed as
the problem is common to both). There would be some range-of-motion
loss (1" or 2.5cm) in the axis. If this is a problem, one should be
able to order a lathe bed and cut it to the desired length for the
mill. (Custom length lead screws are available from Sherline.) This
should be self-adjusting, easy to make and best of all - a cheap fix.

Tony


--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Tim Goldstein" <timg@k...>
wrote:

> I think this group has ballscrewitis. Not every application needs a

ball

> screw and some of the most demanding positioning application don't

use

> them. Need to move a lot of weight and move it fast with heavy
> acceleration? Than a ballscrew is a great solution.
>
> I have been playing with my Taig 2019CR and it is much more

accurate on

> the Z than the Sherline. The Taig solution is simply a slotted nut

that

> is pinched on the screw to adjust the lash. Works great and easy to
> adjust. There are also plenty of nice very high precision acme or
> modified acme leadscrews (.0006" per foot) with matching self

adjusting

> zero lash nuts that would fit right into a Sherline and are very low
> cost compared to an equally accurate ballscrew. It would be easy to

make

> up a split delrin nut or for that matter use another of the Sherline
> bronze nuts and make it into a split nut that you can easily adjust

to

> eliminate the lash on the Z.
>
> Now if the goal is to impress your friends because your Sherline

can run

> faster and jump higher, great get the ballscrews. But if the goal

is to

> eliminate the lash in a manner that is consistent with the design
> philosophy of the rest of the machine I would look at a split nut

or a

> slotted and pinched nut.
>
> Tim
> [Denver, CO]
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http://www.ktmarketing.com/SherlineIncrease.htm

>
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