Leafing through some old turning magaines, I came across a novel
vacuum chuck in the September 1997 issue of "Woodturning" (UK).

There's an article on the Turbo RCD vacuum chuck, which used internal
vanes to generate a vacuum when the unit revolved at speed. No pumps
or through-suction - just a one-piece unit held in an existing
expanding chuck. Mainly wood, and looks hand-made, but marketed at
just under £70 at the time.

I can't trace this item - possibly the firm (Turbo RCD of Nottingham)
no longer makes them.

Can anyone remember this chuck - has anyone actually got one? I'd be
very interested to know if it worked (the "Woodturner" article seemed
to think it did).

And if it's no longer on the market, has anyone any idea how it was
made?

John

"John" wrote in message
...
Leafing through some old turning magaines, I came across a novel
vacuum chuck in the September 1997 issue of "Woodturning" (UK).

There's an article on the Turbo RCD vacuum chuck, which used internal
vanes to generate a vacuum when the unit revolved at speed. No pumps
or through-suction - just a one-piece unit held in an existing
expanding chuck. Mainly wood, and looks hand-made, but marketed at
just under £70 at the time.

I can't trace this item - possibly the firm (Turbo RCD of Nottingham)
no longer makes them.

Can anyone remember this chuck - has anyone actually got one? I'd be
very interested to know if it worked (the "Woodturner" article seemed
to think it did).

And if it's no longer on the market, has anyone any idea how it was
made?

John
=======================
John,
Your description is a little skimpy, but it sounds like they may have been
doing something along the line of the current vane type compressors, or the
princle of the sliding vanes in Mazdas rotary engines. The vanes are
embedded in a cylinder and rotated inside a oviod shaped enclosure. As it
rotates, the spring loaded vanes move in and out following the walls of the
enclosure. Placement of ports in the walls allow air intake, then
compression before being exhausted through the exhaust port. I can't think
of how this could be done within a chuck that I'm familar with, but it's
possible it could be done with some device driven by the lathe. Of course,
that would means having to turn it on and off when you stopped the lathe for
inspections, etc. It would be interesting to see the article.

Ken Moon
Webberville, TX.

"Ken Moon" wrote: (clip) it sounds like they may have been doing something
along the line of the current vane type compressors, or the princle of the
sliding vanes in Mazdas rotary engines. The vanes are embedded in a
cylinder and rotated inside a oviod shaped enclosure.
^^^^^^^^^^^^^^^^^
Actually, the familiar Gast vacuum pump does this, but the chamber is
cylindrical, and the rotor is eccentrically positioned. The Mazda rotary
engine--more properly, the Wankel, is quite different. It uses a cavity
shaped sort of like a figure "8," and the rotor orbits through both lobes of
the "8" as it spins. The earliest application of this was as a compressor,
which, of course, is very like a vacuum pump.

The obvious problem with this whole idea is that you can't stop the lathe
without losing the vacuum.

An interesting discussion. I once tried to make a vacuum chuck from a
vacuum grip used to lift plate glass. I pulled the rubber diaphragm thru
the spindle hole. It didn't hold the vacuum because of leakage and no
way to continuously 'replace' the vacuum. I thought about some sort of
cam, like on a pumping lathe to keep repulling the diaphragm, but never
got roundtuit. IOW, I got what the little boy shot at! Why are y'all
not surprised?

Probably not commercially feasible, but in my ignorance I wonder why
integral compression/vacuum by vane, turbo or whatever that uses
circular motion hasn't been added to a lathe's headstock. Seems a waste
of a perfect setup. Has anyone done this at home?

By now, some of you are probably hoping that I'll try a poorly insulated
100,000 volt ion chuck. Oh well, derision, even flaming is acceptable,
but ignoring ain't.


Turn to Safety, Arch
Fortiter



http://community.webtv.net/almcc/MacsMusings

"Arch" wrote in message
...
An interesting discussion. I once tried to make a vacuum chuck from a
vacuum grip used to lift plate glass. I pulled the rubber diaphragm thru
the spindle hole. It didn't hold the vacuum because of leakage and no
way to continuously 'replace' the vacuum. I thought about some sort of
cam, like on a pumping lathe to keep repulling the diaphragm, but never
got roundtuit. IOW, I got what the little boy shot at! Why are y'all
not surprised?

Probably not commercially feasible, but in my ignorance I wonder why
integral compression/vacuum by vane, turbo or whatever that uses
circular motion hasn't been added to a lathe's headstock. Seems a waste
of a perfect setup. Has anyone done this at home?

By now, some of you are probably hoping that I'll try a poorly insulated
100,000 volt ion chuck. Oh well, derision, even flaming is acceptable,
but ignoring ain't.


Turn to Safety, Arch
Fortiter

======And just who took off for Maine ignoring the sensitivities of the
members of the rec.? Causing a Florida wide manhunt, a dragging of Lake
Okeechobee, and milk carton pictures, inter alia!8^(

Leif

"Leif Thorvaldson" wrote: ======And just who took off for Maine ignoring
the sensitivities of the members of the rec.? Causing a Florida wide
manhunt, a dragging of Lake Okeechobee, and milk carton pictures, inter
alia!8^(
^^^^^^^^^^^^^^^^^^^
And whose slogan should be changed to "Return to safety."

On Fri, 16 Sep 2005 03:54:33 +0100, John wrote:

Leafing through some old turning magazines, I came across a novel
vacuum chuck in the September 1997 issue of "Woodturning" (UK).

I've posted a scan of the original article on
alt.binaries.pictures.woodworking.

Looks a simple device (though the insides may be more complex than
they look.

The maker seems to have vanished or moved. But the chuck looks
shop-made, so has anyone ever seen one, and/or know how it's made?

John

Leif, The Florida manhunt was why I hid in the wilds of Maine, but the
State 'O Maine let Florida extradite me.

Leo, Turn as I say, not as I do, altho neither is safe for turning or
for returning.

John, Thanks for giving us a peek outside the box. Follow up as much as
you can.

Bill Noble, Safety, cost and practicality aside (but please comment re)
are there small motorless vacuum pumps that could be attached to the out
or inboard lathe spindle and vacuum 'fed' thru the spindle?


Turn to Safety, Arch
Fortiter



http://community.webtv.net/almcc/MacsMusings

such a device could be made, no doubt - an internal gear train could
drive a centrifugal vane pump , or of course you could get a GAST vane
pump with no motor (them make them that way) and then drive it with the
spindle, but why would you want to do this?

1. as pointed out before, when you stop the lathe your peice falls off
2. if you slow the lathe down, your piece falls off
3. it will cost more than other solutions, like the one that uses a
vacuum cleaner/shop vac