Turbo RCD vacuum chuck?

======================= 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

======>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."

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

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