PDA

View Full Version : Setting a Steady Rest (continued)



hwingo
02-20-2009, 03:16 PM
I didn't want to steal thunder from the post "Setting a Steady Rest" but I too have some questions regarding the use of a SR.

In a different thread (that I started), many of you guys offered advice regarding turning a piece between centers and adjusting a tail stock to lessen taper. Having followed your advice and realized success I now have a another problem which involves the use of a Steady Rest.

The 12" X 2.5" piece of aluminum that was turned "round" between centers now requires a hole (.95") through the length of the piece. Creating the hole is not a problem (I think:confused: ). Holding the work in a 4 jaw chuck and supporting the end without maring the finished surface is the problem. As soon as I begin centering the work in the chuck I will create unwanted gouges from the jaws. No less, the SR will dig into my finished surface adding additional unwanted scars.

How can I get around the problem maring my finished surface?

Harold

DICKEYBIRD
02-20-2009, 03:35 PM
Glue on a peripheral strip of brass shim stock with superglue to let the rollers ride on, remove it when done? Never done it m'self but should do OK.

ps: Nitromethane is the best solvent for cured CA glue, acetone is next best.

S_J_H
02-20-2009, 03:35 PM
Use some soft pads on the chuck jaws to protect the piece. Simple strips of brass should work.

Couple ideas for the tail end-
A cat head steady for the outboard end,
To make a simple cathead, get a larger diameter tube than your work and fit it with 8 setscrews through the OD evenly spaced at each end to be able to adjust like a 4 jaw chuck. Then slip that tube over your work and through the steady rest. Now dial in your part in the steady rest on the tube using the setscrew combination.

Or- turn a bushing and fit it to your shaft with some low grade epoxy or glue. Then fit the steady over the bushed area. When the job is finished heat the bushing to remove it.

A 12" hole is a good long hole. How are you going to drill it?

Steve

BadDog
02-20-2009, 03:39 PM
Use shims between the piece and the 4 jaw chuck. Perhaps dead soft copper, lead, or even a thin leather belt. Even a sanding belt turned abrasive out would do.

Or, you could make a "collet" type affair from scrap. Basically make a ring with ID just a tiny bit bigger (couple-o-thou) and split the side. Put that on your piece, and the 4 jaw will clamp it to your piece like a collet.

You can do similar to provide a "bearing" (cathead) for your steady, particularly if it is the roller type. The only diff is you would need to clamp it closed with outboard (of the fingers) bolts or something. Again, the ring is clamped to your piece and not moving, the wear/damage will be taken by the ring. If it's the plain-bearing type, you'll need to make sure the split for closing the ring is very smooth and almost impossible to detect (well minimally) when clamped.

BadDog
02-20-2009, 03:41 PM
Looks like everyone wants into the act at once. :D

Good point on the glue. That outboard bearing surface could be turned about 0.002-0.003 over and locked in place with sleeve locker, then heated to remove...

knedvecki
02-20-2009, 04:09 PM
Even better is to make some aluminum soft jaws for the 2 piece jaws of your 3-Jaw chuck. Bore them to the diameter of the work using a spider between the jaws to apply a load to the jaws making the bore 1 1/2 inch deep and forget about the steady rest. You do not need it. This works very good. I have bored 6061 T-6 aluminum 3.500 dia. X 11 inch deep and held size within .0005 inch using this method. If you have to use a steady rest, use a cathead as stated before. There are quite a few ways to make catheads. And for soft jaws, you can make some quick, down, and dirty out of Aluminum round stock with a drilled, counter-bored concentric hole to accept a socket head cap screw to affix it to the moveable chuck jaw. They only need one screw as the friction holds them in place. And you can index them to be used for other diameter jobs

Regards,

Keith

Corm
02-20-2009, 04:11 PM
If you have a milling attachment for your lathe, you could hold your piece in the milling attachment jaws, put a drill chuck in your headstock, and drill it that way. I have a Craftsman/Atlas lathe and a 5/8" chuck that screws onto the headstock threads. I've only used it a couple of times, but it did come in handy on those occasions.

hwingo
02-20-2009, 06:11 PM
Hi Guys,

Thanks for all the suggestions. To answer the question of how do I intend to drill a hole through the length, the answer is, "a section at a time". Once the first 3.5" of length has been drilled, I will then bore that area to 1.75" ID. I then plan to drill the remaining in steps using extra long drills. Once through the length, I will stop .040" under size and ream (in two steps) to the final size.

Regarding the SR, I do not have rollers so I thought about removing the brass inserts and attempting to replace them with Delrin. Maybe that would possibly work also??? Short of that, I suppose I will attempt to fit a collar on the tail stock end for the ST to run on.

Running with suggestions from a previous post regarding SR, I thought about cutting a piece that would "slip fit" on the far end and fitting the steady rest to the piece while it is still chucked and then revove collar and SR and install both (at the same time) on the "out board end" and then secure the SR to the lathe.

Harold