Re: Sherline Z-axis ballscrew feed.

Hello Tony,

All my sherlines came without CNC. Some had the lock lever, earlier
ones did not. Thank you for letting me know that the cnc-ready
sherlines do not have the lever; which makes things easier...

The plain nut will be easier to retrofit with the "star'd" 3/8-20LH
nut I mentioned before. The flat back of the plain nut will provide a
good place to mount the spring steel or music wire keeper for the
added nut to control backlash.

Looking at one of my plain nut models, it also seems that splitting
the beonze nut like is done with the mill drills is viable. Remove
the nut, hacksaw down the "middle" (actually about 2/3 over), and you
can either wedge into the slot created to apply anti-backlash; or you
can tap for two screws, one in each half and use music wire, or a
spring, or a bolt on clamp which can be adjusted periodically.

In other words, there are a LOT of ways to eliminate the z axis
backlash on the sherline mills...

Hope this helps,

Ballendo

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Antonius J.M. Groothuizen"
<agroot@s...> wrote:

> Ballendo:
>
> The saddle locking lever does not come as part of Sherline's CNC
> ready mill or lathe. This must be purchased seperately, or one has
> the option of coming up with their own solution.
>
> Tony
>
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "ballendo" <ballendo@y...>
> wrote:
> > Dan,
> >
> > I agree that your idea has merit. I also agree with TimG that

this

> is
> > all overkill.
> >
> > Is this the new style nut with the little lever for locking? Thge
> one
> > that Joe M says to remove or fix in the "off" position?
> >
> > Because that little lever is key to your solution. I made a

little

> > piece of brass which held it in a semi-closed position, which
> > minimised the backlash...
> >
> > Hope this helps,
> >
> > Ballendo
> >
> > P.S. If you've got the old, non- lockable style z axis nut: The
> > sherline thread is 3/8-20, a common thread. Making a decent nut
> seems
> > a whole lot less work, IMO. You may even be able to add your own
> > version of a "starwheel", like Sherline uses on the xand y...
> >
> > Here's how: Start with a brass nut threaded for the leadscrew.

Turn

> > its OD to fit, and mill or file grooves for the "star" shape. tap

a

> 4-
> > 40 or so hole in the flat back of the existing nut. Using a piece
> of
> > springy sheet, or music wire held by a 4-40 screw in this hole,
> bend
> > til it engages the grooves in your star nut, which is screwed

into

> > position above the existing nut (like the new style locking

lever).

> > Viola, A/b nut.
> >
> >
> >
> >
> > --- In CAD_CAM_EDM_DRO@yahoogroups.com, "Statman Designs, LLC"
> > <titanium@c...> wrote:
> > > I have a question for the group of experts here.
> > >
> > > How difficult would it be to create a Z-axis for the Sherline
> > milling
> > > machines that used a zero-backlash ballscrew drive mechanism?

I

> am
> > not
> > > suggesting that you retro-fit a ball-screw to an existing Z-
> axis.
> > The
> > > Z-axis simply bolts to the X-Y table and the spindle and motor
> > assembly
> > > simply bolt to the Z-axis.
> > >
> > > How difficult would it be to completely replace the Z-axis with

a

> > ballscrew
> > > assembly and then re-mount the Sherline motor and spindle to

the

> > new Z-axis?
> > >
> > > It seems that this would be quite a worth while upgrade for the
> > Sherline CNC
> > > system. The Z-axis is the weakest link in the ability to do
> > repeatable work
> > > on the Sherline. There is no backlash adjustment mechanism and
> the
> > spindle
> > > and motor do not weigh enough to always stay at the bottom of

the

> > leadscrew
> > > pitch. This can, and has, resulted in large jumps of the Z-

axis

> > downward as
> > > it settles to the bottom of the screw pitch.
> > >
> > > Daniel J. Statman, Statman Designs
> > > www.statmandesigns.com
> > > dan.statman@r...