holding threaded parts to mill

[Metal_twister]

How would you hold a threaded fastener by the threads?

Need to modify (mill feature) a part made from all thread.

I made a fixture with a tapped hole, but the flop in the thread clearance allowed parts to not repeat.

Any ideas?

[Geof]

Make a set of soft jaws for a vise using cold rolled steel. Close the jaws on piece of thin metal, 18g aluminum for instance. Tap your hole right down the center of the thin aluminum. Remove the aluminum. Don't lose the work offset you used for tapping.

Screw your part into the threaded hole and clamp the vise.

To make repeating the setup easier make a small reference hole in one jaw a known distance away from the tapped hole and use this to re-establish the work offset next time.

[Marmot_Militia]

I've used nuts, cut a slot axially. Thread them onto your allthread, then clamp in vice. The split will allow the nuts to compress and hold your allthread.

MM

[damae]

Originally Posted by Marmot_Militia I've used nuts, cut a slot axially. Thread them onto your allthread, then clamp in vice....

Hey, that's slick!

[HuFlungDung]

I had a need recently to grip some lathed parts on the threads, and made use of an emergency 5C collet. A smooth bore collet was not positive enough to prevent slipping, because I could only hold the part by by about 1/4" of threads. So, I tapped into an emergency collet, and used an ordinary collet stop to allow the part to butt against. It worked good, and seemed to have good concentricity.

An inexpensive vertical/horizontal 5C fixture would also serve on a mill. Just another idea for you

[ViperTX]

You definitely need a stop to insure repeatibility.....as Hu has so elegantly stated.....

[ttx336]

Originally Posted by Geof Make a set of soft jaws for a vise using cold rolled steel. Close the jaws on piece of thin metal, 18g aluminum for instance. Tap your hole right down the center of the thin aluminum. Remove the aluminum. Don't lose the work offset you used for tapping. Screw your part into the threaded hole and clamp the vise. To make repeating the setup easier make a small reference hole in one jaw a known distance away from the tapped hole and use this to re-establish the work offset next time.

Geoff, I agree with you. I have made extensive use of soft jaws in similar fashion. I may add that if he needs an accurate depth stop he could open the jaws up and clamp on something much wider and then use a Woodruff cutter to relieve the last threads from the bottom of the hole. I too have found making a small reference hole to be of great value, I also like to mark the distance from the reference hole to the "pocket" with an engraver.

Gary

[Geof]

Originally Posted by ttx336 .....I also like to mark the distance from the reference hole to the "pocket" with an engraver...Gary

I think people who are this organized should have something nasty done to them.