Re: [CAD_CAM_EDM_DRO] Myford Lathe Converson.

At 05:28 25/05/2007, you wrote:

>am looking for a solution to the lathe problem
>for my ongoing of Myford conversion.
>*
>*
>*
>Tony, Please give a few details on the Myford lathe conversion. Or better
>yet a lot of them.
>
>Thanks,
>bill.

Bill -

Not a whole lot to report as yet - I have motorized the leadscrew
(see the pic on the CCED front page here:
http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/ ) using a ~ 200 oz-in
stepper mounted behind the bed - the Myford has pre-drilled & tapped
holes along the back of the bed to mount various accessories & the
motor mount is attached to those. Mount is a piece of Aluminium angle
with an end plate attached - this has slotted holes to allow the
motor position/belt tension to be adjusted. Drive to the leadscrew is
2:1 reduction using HTD toothed belts/pulleys.

The leadscrew is almost standard - 8TPI ACME thread, still has clasp
nuts in place. The plain thrust bearing at the RH end of the screw
has been replaced with roller thrust bearings - you can just see the
RH thrust bearing cover between the pulley and the original bearing
mount. This arrangement works very well. My thinking is that for much
lathe work, ballscrews are overkill, and backlash issues are
generally much more controllable than on a mill, hence I haven't
attempted to replace the clasp nuts/screw so far. This also has the
advantage that the lathe can very simply be used as a manual lathe as well.

So far I haven't started on the cross-slide adaptation, but with the
setup as is I can use my Divisionmaster controller
(www.divisionmaster.com) to generate fine feeds and to cut accurately
to a shoulder. This is slightly less than ideal as the DM operates in
degrees - I have to fudge the worm ratio it thinks it is working with
to make 10 degrees on the screen correspond to 1" of movement, or
whatever. So at some point I want to change my firmware to give a
sensible linear readout, and to simply convert between metric and imperial.

Ideally, the DM firmware would also be converted to perform the
electronic gearbox function that has been discussed elsewhere in this
thread. As with everything, too much "work work" intervening at present.

With the cross slide motorized I will probably go for Mach as the
driver, but as I have several PCs lying around that are underpowered
for Mach/parallel port, a solution using a USB device would certainly
be appealing.

Will post more as it develops further, but it may take some time!

Regards,
Tony