Re: [CAD_CAM_EDM_DRO] re:Lathe Rack & pinion.

Hurro..

I'll go have another look at the lathe today to confirm what I see in my
mind's eye.... But how I imagine it will work is that we'll trick the
disable mechanism for the main traveller handwheel (disengages the handwheel
when in power feed to stop it flailing around in the breeze, wish mine had
that...) and leave it at that.

The carriage has very little sliding resistance and can be "pushed" (Leaning
all of my body weight into it...) along the bed even with the pinion
engaged, so I don't think it will be a problem.

There is no way a screw/servo could push the carriage against the lead screw
though, it is a 16TPI Acme thread with a very tight split nut on it when
engaged, it'll have to be left open for 'CNC' mode. I'd also disengage the
feed gearbox from the spindle if it were up to me, save wear on that which
will not be used.

Just got to find out if the owner minds paying for a 1" 5pitch ball screw
about 50 inches long...

Cheers, Chris.

* Design engineer, Assembly worker, Cleaner.
* Ohmark Electronics. PO Box 5302, Christchurch, New Zealand.
* Ph: +64 21 350 603 Fax: +64 3 324 4463 A/H +64 3 324 4462
* http://www.ohmark.co.nz

> I presume when you install the ball screw you disconnect the lead screw

and

> the feed screw? With all three connected, I would presume it would be
> pretty difficult to drive the carriage back and forth with any
> screw.....sort of like having THREE gears all meshed together at once.
>
> Yes, laugh at the three gear mesh if you like, but I actually saw a gear
> train that was designed that way once. I was checking the job and sent it
> back for a redesign.
>
> Smoke