In article , Jim Wilkins
wrote:

"Joe Gwinn" wrote in message
...

PrecisionmachinisT makes the point that it's better to have the
included angle be slightly too small, as the jaws will spread
slightly
and yield a firm fit, versus the wobble if the V is slightly too
obtuse, so the 0.3 degree delta may have been intentional. The old
lathe makes made these kinds of tweaks all the time.

Joe Gwinn

Could be, a kinematic fit may be good enough for the steady rest since
it doesn't slide and wear.

The bottom of my South Bend steady was scraped and frosted but the
micrometer stop's vee groove finish would be unimpressive on a Chinese
part.

There are some scraping marks on this steady rest as well. But they
don't look like someone worked on it all day.

If you recall, I got a 70-degree included angle conical mill bit for
making Vee grooves to fit the Clausing. The resulting grooved blocks
are quite stable on the ways, not being in the least wobbly.

Joe Gwinn