"Prometheus" wrote in message
...
On Wed, 9 May 2007 09:49:21 -0700, "Charles Friedman"
wrote:

The first is that most wood lathes (at least, the ones I see) are a
gap-bed style. To fit and use a compound slide, you sort of need ways
that are made of a solid piece. A person could always mount ways on
the gap bed, but you'd lose some swing, and it'd be tough to align
properly (IMO.)

Many, if not most, medium (14" to 24") engine lathes are gap bed.


The second is that a belt drive really isn't good for metal turning.

Most all engine lathes are belt drive. It wasn't until the CNC that direct
drive became common and is still only used on them. Manual machines use
belts. I've made hundreds of parts on lathes driven by flat leather belts,
more with the more modern rubber belt drive.

You want back gears if you're going to be turning slow, so that all
the torque isn't lost, and you need them if you expect to be able to
cut threads.

That's true. The gearing is between the spindle and feed rod/leadscrew. The
spindle is still turned by belts. If the spindle changes speed for any
reason, the feed rod or lead screw changes with it as they are geared
together. I have changed spindle speeds in the middle of a threading
operation with no loss of accuracy.