Threading Cockup

[savarin]

I learnt how to do and not to do something today.
Dont cut the keyway in a shaft before attempting to thread it with a die.
I cut a 5mm wide keyway in a 12 mm dia shaft, then attempted to cut the thread by holding the die in the lathe chuck (no holder large enough) and holding the little stub shaft in a drill chuck in the tail stock. (all by hand not powered)
I failed to realise that the width of the cutting teeth in the die were small enough to fall into the 5mm key thus jamming the die and sitting it off centre.
I solved the problem rather brutishly by holding the shaft in the vise, gripping the die with a large set of swan neck pliers and whilst tapping the die opposite the keyway so it would stay out of the keyway and applying the rotation force required to cut the thread.
It actually worked to get enough threads for a nut.
Sometimes a little fig jam is sufficient.

 

[RJSakowski]

In machining, the order of operations is all important!

 

[David S]

I wonder if you could have just placed a sacrificial piece in the key way and remove it after cutting the threads?

David

 

[Bob Korves]

Single point the threads?

 

[T Bredehoft]

You are to be applauded for your solution. Often we have to think outside the box (normal considerations).

 

[savarin]

Thanks Tom, I was feeling too lazy to sort out the change gears and never considered a sacrificial piece .
I had just managed to steal an odd half hour in the shop so wanted to make the most of it.

 

[Paul in OKC]

Even in single pointing, you would want to do the threads first. Although in this case..............