Holding small parts

See my clamping suggestion from a day or two ago for Bob's cut out coins.

super glue to steel. surface grind, heat part with propane torch to remove.

Karl

And after it was fired, the part wouldn't fit - clay shrinks when fired.

Thin (not thick and foamy) double-stick tape might do perfectly well, if the parts are clean and flat. The superglue already suggested would also work. If the part is prone to creep during filing despite the tape, a couple of stops to catch the edge of the plate might be all the help it needs.

Hot glue is yet another option. Fixturing alloy would be another.

How about making aluminum soft jaws for your milling vise with a shallow horizontal vee notch in the top edges, or a few dowel pin holes?

Paste wax an area on your mill table, and one of the subject parts with a good heavy duty paste wax. Mold release wax is premium, as sold by fiber glass venders.

Lay the part down on the side you wish to machine.

Lag the part up with body filler, or tooling plastic. Modeling clay can be used if necessary to stop the plastic from getting under the part in areas that would trap and lodge the part in the cured plastic mold.

Upon hardening, gently clamp the mold as is, and machine the back flat with well used tool. Body filler and tooling plastics are most often very abrasive.

Flip it over, clamp it down, and machine the part.

Pop out the part, replace with another, and repeat.

Mount it on a wooden dop with sealing wax then either clamp that or work freehand with a decent handle. Heat to release. Might need a few brass panel pins with their heads just lower than the surface of the part round the edge to resist lateral forces, but it's gotta be easier than carving a pocket and wax will clean off easier at a lower temperature than superglue. I've lapped dozens of copper seal washers I annealed for reuse that way last time I rebuilt a diesel.

Machine a pocket in a 5C emergency collet to hold the part and face off the part in your lathe.

on 3/12/2009, Ecnerwal supposed :

Agreed. I've had good luck with double sided sticky and light cuts.

Wayne D.

Thanks everybody!!

I decided to try the thin double sided tape idea first. (BTW the part is not round so some of the replies would not work). Milled a thin slot across a 1" x 0.1" piece of aluminum. Slot depth approximately 0.025" deep. Simply enough to give me a shoulder against which the part will abut while I push the file. Used thin scotch brand double sided tape. Worked like a charm. Merely sliding the file across 4-5 times, I removed almost 0.010 material. Was shooting for 0.007±. Very fast. Takes longer to find the end of the scotch tape than to complete the project. It surprised me that I could even file backwards, whereby only the tape was holding the part i.e. no shoulder for the part to rest against.

Thanks!!!!!!!!

Ivan Vegvary

Lapidaries grind and polish rocks freehand. They use dop wax.

Hey Ivan,

Glad it worked out for you. Me??? I had no idea what to do!!! BUUUTTT.... I do hope to catch at least one of the NAMES SEMINARS in mid April which would seem to be of interest to you and many of us:

Noon Saturday... Jerry Kieffer "SILVER SOLDERING & FABRICATING SMALL PARTS"

and at 4PM.. Ron Grimes "WORKING WITH SMALL CASTINGS AND PARTS".

Take care.

Brian Laws>Thanks everybody!!

friend of mine polishes facets on glass chunks (up to about 50lbs apiece) by embedding them in a puddle of paraffin, using a vibrolap, then gently heating them up to get the paraffin off.