What size wire to use for 4-40 threading die? 4-40 wire are too small.

mecam, what type wire are you planning to use the die on? You can not cut threads on music wire unless you take the temper out of it.
2 Piece

Hmm, I was planning on using K&S music wire. What kind of rods can I cut with my 4-40 die?

have you ever tried this b4? you need steel (drill rod) that is soft and when you do get the steel yur gonna have a difficult time not twisting the steel when ya try and cut it. can ya just use 4-40 rod that has thread on it now? -Tin-

mecam:

I have the Rodchuck system and use it to make 4-40 pushrods. The base stock is 1/8" welding rod. The Rodchuck uses a 2 die method. 1st pass is with a 5-40 die which sets the correct thread count then a second pass with the 4-40 that reduces the threaded diameter and gives the correct sizing. Works like a champ.

Any round stock will work. The test is if you can EASILY file a flat on it then it can be used to cut threads.

Dan

I normally use 4-40 threaded ends. Sullivan products sell them in packs of about 20, they are about 1" long (same as what comes in one of their pushrod packages). Then I take a piece of brass tubing, use as a coupler, that will fit over the threads and the appropriate size music wire and solder together. Sorry I can not remember the sizes. Make the brass coupler 1" long so that it fits about 1/2" onto both the threaded end and the music wire. Hobby shop "silver" solder, Stay Brite, Hobbico, although not real silver solder, will provide a strong enough joint. K&S brass tubing will work fine, just make sure you do not use their 1/8" soft brass tubing (used for fuel line setup). And make sure the solder is "sweat" up and into the coupler.
2 Piece

I gave up. I'll just use a sullivan 4-40 rod and just solder a threaded 4-40 coupler on the other end. This way I have the exact lenght that I need. I just don't understand the purpose of the die if it can not cut correctly. I just wasted $15.00. Thanks for all the help guys.

mecam, threaded couplers are OK, I suppose. They are usually made of brass, and I have found out that they are weak where the coupler body and the threads meet. Check them out and draw your on conclusions. The threaded ends I described earlier are made of steel, and when properly "silver" solder, inside the homemade brass coupler produce a stronger coupling than a brass 4-40 threded end.
2 Piece

The solder threaded ends I got are from Dubro. I'm using these for elevator rod on a 1/4 edge 540.

Yeap, those are the ones I personally feel are weak, or at least they use to be many years ago. I suggest you give them a little bending test and see if they bend easily where the threads meet the coupler.
2 Piece

I have been purchasing wire from McMaster Carr for this for some time. The best wire I have found is Oil Hardened wire .107 in diameter. I have used .125 in mild and hi-carbon and even stainless and I have experienced a work hardening effect at the start of the thread. This has been a fracture point in one case. The best method and control rods that I have found are the oil hardened wires .107dia run through a "QUALITY" die nut with a lot of tap magic. I screw the wire in the die with a cordless drill. I have made bunches of these and their on My 40% EDGE. If you are interested I can come up with a e-mail and part # from Mcmaster Carr. Music wire and the KS stuff is too hard. By the way, I think the E70 and E71 series stuff is to soft. JMO

Personally I would not use the soldered on ends, it's a potential source of failure. The heat needed to obtain a good joint weekens the kwik link IMO. I purchased some 5-40, and 4-40 dies from Microfsteners. I use 1/8" welding rods, I have found the nickle alloy rods work better than the mild steel rods. You can purchase a handfull of 36" welding rods from a welding supply store for just afew bucks that will last almost forever.

Vince

Vince, do you have the material specification for the nickel alloy rod ? Thx.............

The Nickle alloy rod is ERNiCu-7

The mild steel rod is ER70S-2

I have used the mild steel rods in short applications with no problem, but if the length is more than about six inches they tend to fracture at the end of the thread. Now I use only the nickle alloy rods.

Vince

Vince:

Thanks for the tip on the Nickle alloy rods (ERNiCu-7). I have been using only the ER70S-2. While I haven't had a failure yet, I will switch to the nickles.

Dan

The correct rod size for 4 X 40 is .112
The correct rod size for 2 X 56 is .086
The correct rod size for 6 X 32 is .138

Greg