View Full Version : NAMES Question on Ball Turning

04-30-2007, 12:11 AM
Some visitor at the NAMES show was talking with me about ball turning, and said a shop he'd been at had made one from an old door closer. He didn't know quite how they'd arranged that, and I've been racking my brain since to figure out what they might have done.

I can see a pivot (used by the arm) but it doesn't immediately suggest any useful geometry. Hydraulic damping might have some advantage in smoothness, but tool rigidity would probably count more than smooth rotation.

Altogether I'm drawing a blank on how to use the door closer mechanism for a useful turning device. Has anyone else seen something like this used or can envision one? (P.S. I can get a door closer for the price we all know and love.)

04-30-2007, 01:35 AM
Surely the door closer is intended to provide a controlled rate of rotation using the spring and dampener. There's a lot of door closer geometries - I wouldn't be surprised to find one that would work. It may work like the throttle cables on my Harley, frinstance.

04-30-2007, 06:04 AM
On the old closures you had more adjustments,closing rate/speed, at the very end you have a speed up called a latching rate, the old arms had a theard run on the section you hook to the door to adjust the fit. You could flip the arm for right or left handedness. Don't know how you would get it to work as the base or spring can would have to have the mounting to be rigid as when the screws get loose they tend to move in about 3 different direction at once.

The newer ones are made as once used ones cheaper to pitch and replace than repair as most no longer supply kits. As the newer ones don't have as much power they tend not to move as much and they are slower for saftey sake, and some the latching rate closing the door sucks thats why so many store doors move when the wind blows.

With the end of the tooling assembly hooked to the closure arm. If you let the arm go after the piece was rotating and the ball was large enough in dia and the cut deep enough for a slow movement the closure would keep the tool in constant contact with the metal ect. and you would have to watch it at the end of the cut. I thing it would be a pian on small dia ball turnings. But that just MHO