View Full Version : Radial air motor for machine slide power?

05-09-2003, 12:32 AM

Why have these air motors not caught on with machine slide power? I drawed one of these years ago and thought I had invented it till the patent search showed otherwise. I was wanting a
drive for my chinese lathe with the sticky cast iron nuts on the screws.
Lots of uses around the shop. I'd bet I can't afford these, but I could build my own. Looks to me to be the perfect positioning motor. A speed needle valve and a solonoid for direction, encoder feedback.. simplicity.
Who has a source for cheap lil bitty pistons and rods?

05-10-2003, 01:44 AM

Junk yard. Just remove any metal that don't look like what you want. Make bronze nuts for your lathe and you will be much happier.

BTW, my toolmaker friend showed me his radial motor (like those) twenty yearsago, and he had it for ten years then. It fit in a bear bottle cap - 30,000rpm @ 120psi (or so) and had a reversing lever.

And the Rudy radial looks like an air motor too.

05-10-2003, 02:17 AM
Air motors, and for that matter just about all air tools are terribly inefficient. Your compressor would be consuming 2-3 HP to deliver a mere fraction of a HP at the tool. Air is a very compressive media so doing any fine control becomes difficult because of overshoot characteristics.

They have done some interesting control system using hydralics, where a linear encoder is mated to a hydralic cylinder to provide precise high force linear motion control.

Keep thinking, tinkering, and imagining. One day you'll hit it big.


05-11-2003, 10:16 PM
Rotate, I had a air over oil cylinder system on this old HF multi purpose machine. It worked great, no stalling out. BUT. was slow as christmas. I was using a gear pump operated by a stepper to meter the oil into the cylinder, with a bypass solonoid to speed it up. All was with a cable actuated quadrature encoder off a old robot.
THE HF was junk and is history now. I got a 1976 bridgeport CNC and am tickled pink.

05-11-2003, 10:33 PM
Rotate is right about air motors in general, However; I've got an air drill that will either bust the bit or break your wrist if not careful. Fine control remains a problem.