"Jim Wilkins" wrote in message
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On Nov 29, 9:20 am, "Ed Huntress" wrote:
"Jim Wilkins" wrote in message

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On Nov 28, 11:19 pm, "Ed Huntress" wrote:

"Jim Wilkins" wrote in message
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I'm sure there are many possible solutions. ...
Ed Huntress
The problem is making the first headstock spindle without another
lathe. Once you have it you can machine a better one.

In my case someone would likely offer me a good lathe cheap *after*
seeing the one I struggled to make.

jsw

I wouldn't attempt this without access to another lathe, unless someone
made
it a group or club project and made the necessary machined parts available
for a reasonable price.

--
Ed Huntress

I think it could be achieved starting with a simple machine that's
adjusted into place. For example my dead-center lathe could bore the
headstock pipe for your cast concrete one. Slide the headstock down
the ways over a long fixed boring bar.

The practical application is temporary oversized equipment to
recondition old worn machines. I'd like to rig up a milling head with
enough X and Y travel to clean up the ways of my surface grinder. It
only needs to slide along one axis while cutting, and can rest on
parallels for the other axis.

jsw

Maybe. I've thought about some of this in the past, and I don't see being
able to bore the headstock from the bed without a pretty fancy, and strong,
temporary boring rig. If it was just a straight bore, maybe. But I've
changed my thinking on that to include a tube bored on another lathe; a
careful setup to cast it in place when the headstock is cast; and a
honing/lapping rig mounted on the new lathe's bedways, rather than boring,
to finish it off. The loads will be much less and you won't need a
controlled feedrate. The whole affair would be simpler.

But I'm not saying I have all the answers for this. It's just a lot of
thinking and speculating on my part. Nor would I want to discourage anyone
else who wants to give it a try. Viva the experiments.

As for finish-machining bedways, you might like to see my idea for a
right-angle grinding head that moves on ordinary, low-accuracy ways
(Thompson round ways), with two axes of stepping motors that respond to
optical drives that follow a laser beam -- or maybe you wouldn't want to see
it, come to think of it. It was pretty rough and crude, but there's an idea
there. (No, I don't have any CAD files of it. I sketched it around 30 years
ago.)

--
Ed Huntress