"Wes" wrote in message
...
"Ed Huntress" wrote:

Just in case you run into a fussy old fart, like me g, be aware that the
traditional meaning of a "live center" is one that is driven under power.
In
other words, a headstock center.

A ball-bearing center for use in the tailstock is a ball-bearing dead
center.

You won't have any problem using the term the way you're using it, unless
you get an old guy on a bad day. d8-)

I've always heard of the bearing center called live and a solid center
called dead.

Then you aren't old enough. g Or you didn't steep yourself in old
machining books for a decade or two.

A live center is powered. A non-powered center is dead. If it has a plain
bearing (some did), it's a plain-bearing dead center. If it has ball
bearings, it's a ball-bearing dead center. Of course, if it has no bearing
except for the center cone, it's just a plain dead center.

Like many things in machining, the original meanings have gotten lost from
common useage. But that's the way it always was, and I think most machinists
used the terms that way, at least into the '60s.


But when a solid center is in the headstock, it is indeed live as in
rotating with its
support and solid centers with lubrication have been used in the tailstock
that is a fixed
support.

Bored Ed?

Nope. I had a great day catching bluefish across from Staten Island.

There are other old machining terms that have gotten lost or corrupted. I
used to keep track of them, and I'd often comment on them, with the old
meaning and the new, in articles I wrote for _American Machinist_. I've
forgotten the rest of them.

While it's on my mind, though, the machine is a jig borer, not a jig bore.
g And a lathe with no saddle, cross-slide, or tailstock is a speed lathe.
A short-bed lathe with no tailstock is a chucker. A measuring tool is
spelled "gage," not "gauge," based on a precedent set by _AM_ back in the
1870s.

My wife considers me to be a specialist in boring machines, and other boring
things.

--
Ed Huntress