Threading RC Airplane Push Rods

Threading RC airplane push rods - back in the 1990’s a company called “RODCHUCK” sold a push rod threading kit, that company is defunct. Their kit consisted of 4 dies and a die holder. The larger die was placed in the holder,  the holder slipped over the rod and you started threading the “welding” rod.  Since the kit is no longer available I purchased the dies, 2-56, 3-56, 4-40, and 5-40 off Ebay. The dies are around $6.0US, shipped free from China and for the number of times I have used the dies, they hold up fine. I also bought cheap die handles off Ebay, one for each die so I don’t have to put in and take out the dies from the handle. You can also get dies at the hardware stores, machine supply shops, or K&S dies at the hobby shop.

former Rodchuck kit

The rod we are using is mild steel welding rod is obtained from your local welding supply shop.  1/8” diameter rod is used for 4-40 threads and 3/32” rod for 2-56 rods. A tube of rods cost about $16.00 and has about a dozen 36” long rods in the tube, enough rod for years of large rc airplane pushrods.

For 2-56 threads, you start off with the 3-56 die on the 3/32” rod and thread the length you want,  I normally thread an inch of rod. The rod length is sized for the distance from the servo arm to the horn and the type of connector at each end  of the threaded rod, either a clevis or a bolt thru ball ink connector.

For 4-40 thread, you start off with the 5-40 die, then go to the 4-40 die. Be sure to use a steel cutting fluid, and take your time,  1 turn in, ½ turn back and for forth. If you over torque the die, the die will crack, take your time.

A couple examples of my threaded push rods below, I prefer a mechanical connection over soldering, I have had a solder joint let go, some builders are good solder’s and prefer the soldered joint.  I have not had a failure so far on my threaded rod, my oldest warbird with many flights on it, was a P-51, it was 8 years old until it mid aired with a P-47. Time will tell how these threaded push rods hold up.

A PDF of this pushrod threading post is at  this link.