Clamping Threaded Rod?

[JWB_Machining]

Hey,

I have a piece of threaded rod that i have to turn down half of it to a smaller diameter and rethread it. I've never clamped on a piece of threaded rod however and was wondering what people use to be able to clamp it in a three jaw chuck without ruining the threads.

[Mcgyver]

just hold it directly and take light(ish) cuts. threaded rod isn't precision stuff, should ok...worst worst case is you have to chase it with a die

if its more fussy, wrap some coppy sheet around it before clamping

if that isn't good enough, make a split bushing. take a round slug of metal a little larger than the thread OD, spot drill, drill and tap then split with hack saw or bandsaw. this will hold the threaded rod without damage but because of the amount of clearance you get with threaded rod it may not be that well centred.

[djr76]

Ive held them in 5c/16c collets just fine.

[dertsap]

if you have some brass shim stock you can give it a wrap

[Konrad]

Take two nuts and cut about 4/5 thru...your jaws will push on the hex of nuts.

Konrad

[Geof]

Get a long coupler nut and cut a slit in it. Screw your rod in and then really reef down on the chuck jaws to close it up somewhat like a collet.

[One of Many]

If you can cut a 3/8 thread down and re-thread it, can you get away with drilling into it and tap it for inserting a locktited stud?

Depending on how concentric you need the threaded rod to your new threads. I don't aways trust the OD of threads, when it is the pitch diameters I want concentric. For a cheesy but reasonably accurate setup, I'll grip up any old scrap short piece of bar stock rod. Face, Drill and tap through it on center with the tailstock and it should run true as long as you don't remove it from the chuck. Then thread in the threaded rod and use a lock nut to keep it tight in the scrap rod.

Some hardware and fastener suppliers do offer reducing studs with mixed threads on either end. Another cheap and lazy option.

DC

[Konrad]

Originally Posted by Geof Get a long coupler nut and cut a slit in it. Screw your rod in and then really reef down on the chuck jaws to close it up somewhat like a collet.

I find cutting it half way will tighten the nut so it's going be hard unscrewing the rod. A long nut like this would be better cutting it in half and using like split jaws. I have done this, most often I have regular nuts [two of them] cut about
4/5 thru into a hole, which is drilled very close to one flat of nut, about
1/32 away, then the nut is springy and it will always loosen up, use a good
grade nut..[alloy].
Konrad

[sti2011]

Have had to customize more than a few nuts and bolts myself. If you have an emergency collet, drill and tap that, then your concentricity will still be there. This has also worked on parts that there is just nothing practical to hold on but a thread. I despise holding over the thread as they are usually not "really" a collet size and gage contact is near nothing. (will rip out if you are aggressive) Also with the collet depending how you run your spindle and tooling the part will tighten itself in, not out!
I've even done this with a three jaw chuck and it worked the nuts. Had a cut-down job on some really nasty moly bolts.

[cam1]

Nice new Avatar dertsap, reflects the times.

regards

[dertsap]

its my tribute to the economy