I am looking for 12" steel push rods with 4-40 cut threads on both ends. I don't know if the Dubro's are cut or rolled. I'd like to buy a small tube of 20 or so (or more if the deal is good enough). Does anyone have a favorite place where they buy them?

TIA

my lhs sells them. just a shame they are a few miles away from you. try towerhobbies.com ive never used them but ive seen their online stuff. may have what you are looking for.

Bob,

Try this site: http://www.mcmaster.com/

Page 2981

You can get it in 2', 3' and 6' lengths

sideshow - try "http://www.microfasteners.com/catalog/products/TNM.cfm"

Ace hardware will sell them by the tube.

Take a look at this site http://www.rodchuck.com/.
Ray

Any particular reason you're looking for CUT threads as opposed to rolled?

Probably because I told him that in my experience the rolled threads are generally a little "looser" than cut ones. Additionally, a cut-thread pushrod is typically a little stiffer because the diameter of the pushrod is slightly larger (in a rolled thread, the material is pushed up to form the peaks of the thread; in a cut thread the rod must be as large a diameter as the highest peak of the thread).

Rolled threads work too - but IMO you are much more likely to need a fairly thick threadlock compound to fill in the gaps.

Gordon

I also like that the rods are a little thicker since they have to cut a 4-40 thread from the diameter of the rod.

On the downside, cut threads have nice little stress concentrations at the bottoms of the threads. This is particularly bad if the threads are die-cut, as opposed to cutting them on a lathe. The material also has to be soft enough to not chew out the die on every cut. I don't really see Dubro, GP, etc. heat treating the pushrods after cutting them.

I'd go for rolled threads anytime. You can fix the slop in clevises with thread lock and locknuts. There are gap-filling compounds sold as well. Loctite have a thing called 'bearing mount' which can take up a few thousandths of an inch.

Another source of rod is bicycle spokes. As far as I know, these always have rolled threads. They tend to be made of better material (stiffer) than most of the RC hobby pushrods I've seen, to. I can't say whether they'd be available with a 4-40 thread, though.

If you still have a stiffness problem, some close-fitting carbon fibre tube glued around the rod can help.