[How-To] Using dies

I am surprised no one mentioned this. The chart you were referencing is a TAP and DRILL chart for making internal threads. The same data will not work for making external threads.

I have had to do what you are doing many times to make a bolt work for an application. Starting from an existing bolt is better than welding a head onto stock. that weld will never be near as strong as the forged bolt head.
 
I am still thinking of this. A table with numbers is just that. For me, I get numb to them. I have never been very good with numbers as they get to be a blur. Now think of what you did; what a wonderful demonstration of a root diameter and even an illustration of the effects of tolerance and precision. that sort of visual aid is invaluable to my learning. I can suggest that you will enjoy these learning opportunities much better if you haven't spent a weeks worth of spare time successfully refining the other end of the part.
 
Flyinfool said:
I am surprised no one mentioned this. The chart you were referencing is a TAP and DRILL chart for making internal threads. The same data will not work for making external threads.

I have had to do what you are doing many times to make a bolt work for an application. Starting from an existing bolt is better than welding a head onto stock. that weld will never be near as strong as the forged bolt head.
Click to expand...

Ok I’m confused...
How would I determine the major diameter if I were turning down a shaft to be threaded with a die?


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DavidR8 said:
Ok I’m confused...
How would I determine the major diameter if I were turning down a shaft to be threaded with a die?


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Click to expand...

I always turn the major diameter to the nominal thread diameter or a thousandth or two smaller.
 
DavidR8 said:
Ok I’m confused...
How would I determine the major diameter if I were turning down a shaft to be threaded with a die?


Sent from my iPhone using Tapatalk
Click to expand...

It does not matter what cutting method you are using, A die or single point should give the same finished thread. The dimensions in the machinery handbook are for the finished thread regardless of how you go about creating it. Since a die is a cutting tool, it will not make the diameter bigger (unless the die is dull and raising a burr) so the majaor Dia for an ecternal thrad is the size you want to turn it to. There are time that I will cheat a bit smaller on the major dia to reduce cutting force with a die, same as going slightly oversize when tapping. But I only do this if needed.
By using the die on the lathe you can take it to the correct dia and then do the thread, if it is to hard turning the die then the part is still set up to take off another couple thou to make it all work better.
 
Right sorry I was having a brain stall.


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