DEALING WITH 4-40

[riversidedan]

Not sure what you mean by that. A die should look something like this:
View attachment 392247
The die is usually round, but doesn't have to be, and it has gaps between the threads, for the swarf to be ejected. Does your die look similar to this? Some dies have a split, but they don't have to have one.

yes I know what a die is and am not stupid as some here seem to think>>>>>>>>>>like I said. thiers teeth on one side but not the other, I just returned it so no pic , sorry..................but no, the teeth didnt go all the way thru the die

 

[riversidedan]

I put the die in the chuck to keep the everything straight

me too

 

[riversidedan]

Starting a die true to the work is a problem in even the larger sizes, 1" and above. The method I use for smaller screws, Nr 2 and Nr 00 should work for a middlin' size like Nr 4. Start with the proper size, .060 +(4x.013). That yields 0.112". Then extract the few thou for top clearance. A very few thou for Nr 4. Then for the first 1/4 inch, remove down to .113 less .025 (.088") for a slim fit internally. Once the die is slid onto the undersized section, start cutting. For something as large as Nr 4, I would put the stock in a lathe and hold the die by hand or maybe a pair of "Channel-Locks" so it can be released quickly.

The above is for making long threads, like all-thread. For machine screws with 4 or 5 pitches, I just chuck the part and use the face of the tailstock chuck to square the die. There are occasional times when the screw end is exposed. There I trim the end as described above, run the die, and before removing the die clip off the undersized portion and excess length and trim up with a file. It works well enough for the small sizes I deal with. Nr 4 should do well enough.

For long threads I often use oversized stock. Just trueing up a half inch or so for the die to bite. The most common thread I cut is 2-56. The rod is 3/32 brass. At ~.093, a fuzz over size for Nr 2 at .086. Once the die is started, it will shave off that little bit of extra. Be advised, brass is soft enough for that "shenanigan". As is raw aluminium. On the other hand, steel is tougher and may not shave so easily.

EDIT: adjusted Screw sizes
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>>>>>>>>the rod is steel

 

[WobblyHand]

If the steel is hardened, a cheap die will have trouble with cutting it. Can you file the rod, and it cuts? Or does the file sort of glide over the steel without cutting? If you can file the steel, a good die can cut threads in it. If you know this already, my apologies.

 

[T Bredehoft]

I believe you'll find the "skip teeth" in your die are to reduce the need for extra tool pressure while cutting the threads. They will certainly cut good threads.

 

[riversidedan]

If the steel is hardened, a cheap die will have trouble with cutting it. Can you file the rod, and it cuts? Or does the file sort of glide over the steel without cutting? If you can file the steel, a good die can cut threads in it. If you know this already, my apologies.

the file glides over the rod so I use a dremel drum sander to round the end off

 

[WobblyHand]

the file glides over the rod so I use a dremel drum sander to round the end off

This is a good clue.

A carbon steel die won't cut hardened steel, or won't cut it for long. If it's hard enough, you can damage the die. I'm not sure how hard your steel rod is, but I'd go with a HSS die in 4-40. High Speed Steel will cut better and longer than carbon steel. It also stays sharper for a longer time.

As an alternative, you might also consider using some different steel rod that isn't hardened. That way you could use a cheaper carbon steel die for your threading.

Hope this helps.

 

[RJSakowski]

wanting to make some small threaded rods with a 4-40 die and wanting to know whos had experience threading that small of rod.
will put the die in the chuck and rod in the TS chuck and have to force the rod in, the die is octagon so needs to go in the chuck.
anyway the setup is good just wondering whos messed with small rod threading////////



gentleman....................drill size for a 4-40 is .0890 or #43 the short steel rod to be cut is .0935 sound like its too big for the die??? and yes the rod is chamferd

yes I know what a die is and am not stupid as some here seem to think>>>>>>>>>>like I said. thiers teeth on one side but not the other, I just returned it so no pic , sorry..................but no, the teeth didnt go all the way thru the die

It is difficult for forum members to know how much experience someone requesting help has. From your original post, it appears that you are new to the craft. Dies are usually round or hexagon. A 4-40 thread has a .1120" nominal outside diameter. The nominal drill size for tapping internal threads for 75% thread engagement is .089". All this would indicate a lack of familiarity with cutting threads.

For the most part, forum members try their darnedest to help others solve their problems. This is often done with insufficient information to properly assess the situation. Nevertheless, we will persist in our effort to help you find a solution.