Re: Adjustable Die For Crank Threads

[PM T2]

to the best of my knowledge, these dies do have have the flexibility to be able to travel all the way over the damaged threads. The adjustability only equates to a range that might be several thousandths of an inch, but that’s all. They are hardened tool steel, and don’t have a lot of flex in them. We used to machined male threads in zinc with dies like that, but typically if we were adjusting it, the reason was to make the thread SMALLER as the cutting edges of the die started to wear.

A threading die will cut steel away and may cause you even MORE problems if you’re not careful with it.

For peened over threads such as you describe I keep thread files around, and use them to restore the original form of the thread as much as possible as a first step. This is followed by a "thread restorer" that rolls or forces the existing thread back into its proper profile without actually cutting any steel.

I’ve saved many crankshafts using the thread files and chasers, but there’s been many others that just had to be welded up and have the threads re-cut on a lathe.

Hope this helps eh.

Best,
Chris S

He's livin' in his own private Idaho..... I hope to go out quietly in my sleep, like my grand-dad did..... and not screaming, like the passengers in his car...