1590Re: [mlathemods] Re: live center woes
- May 1 7:14 AM
----- Original Message -----
From: "Peter sanders" <psanders@...>
>David Lee <dsleeI@...> wrote:
>> A live center turns with the work.
> A live centre in the headstock though turning with the work
> is really not rotating about the workpiece per se.
There's a choice between "live" and "dead" centres at both ends of the
The oldest, simplest and indeed most accurate form of lathe has two "dead"
centres - two tailstocks if you like. It is driven by a cord either on the
work or on a pulley rotating on one of the centres.
Watchmakers call a dead-centre lathe "turns". Woodworkers tend to call them
"pole lathes" from the springy pole used to return the cord each stroke,
though a spring, handwheel or treadle wheel can be fitted instead.
When I was a youngster I made a metal-working dead-centre lathe out of
steel flats and studding. I cheated by turning the centres on a
conventional lathe, but it would have worked just as well had I filed them
carefully, like our ancestors did.
So the simplest terminology that fits the bill is to call a centre "dead"
if the point doesn't rotate, and "live" if it rotates with the work,
regardless of which end of the lathe.
Yes that does mean that a pointy bit of metal on a Morse taper becomes
"live" when fixed in a headstock spindle and "dead" when fixed in a
tailstock barrel, but hey, you can't win 'em all.
Just to upset you some more, I was taught in Olde Englande that headstocke
centres should be softer steel, so that they could be turned accurately in
the spindle for top-class work, while tailstock centres should be very hard
to resist wear. So we shouldn't be swopping those point bits of metal
between ends anyway.
When I came to fit out a workshop, I couldn't get 2MT soft centres
anywhere. Has the toolpost grinder killed them off?
Also 56 and from England
- << Previous post in topic Next post in topic >>