06-14-2012, 07:10 AM
(06-12-2012, 05:20 PM)f350ca Wrote: Nice work Mayhem. I've had roller and brass steadies and not sure which one I prefer. The surface has to be relatively smooth for either to work, you or at least I have to turn the surface if at all possible to get it round, its usually slightly oval or some odd shape. Once its smooth the brass runs nice with lots of oil. Cuttings don't bother the brass fingers, they get wiped away, where they just love to go under the rollers. The steady on my 18 inch lathe is heavy enough I have to use the crane to put it on, it has rollers and what I thought was a CHEAP plastic knob to hold the top half closed. Well that plastic knob makes a great relief valve. Was hogging some pretty heavy cuts close to the steady, one of the cuttings went under the roller and blew that knob to pieces. Not sure what would happen if it couldn't open, maybe twist the shaft between the chuck and the steady. Moral of the story, don't rule out the brass fingers, I've never had trouble with them.
Having been around a great many roller based steady rests, I can tell you exactly what would have happened. Given the hp involved, the chip would have been rolled flatter, and the part would have suffered a scar shaped, oddly enough, just like the flattened chip. When I was in QC, I constantly rejected parts that were marred up from inattentive operators who let the chips build up around the rest until they were rolled in. On a finished OD, that required another operation to rework the diameter, provided the size would allow. That's another reason to keep the chips under control.
I prefer roller rests, and stick a barrier of some sort, like a plastic coffee can lid with a hole in it, just in front of the rollers. Works pretty well to keep the chips out.