[How-To] Using dies

[DavidR8]

For a class 2a thread, OD range is 0.4987 to 0.4906". Hit anywhere inside this range, Dave.

Thanks Mike, feel a bit silly having read the wrong column


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[mikey]

You'll notice that nobody here will rag you about that because every single one of either has done it or will do it. You're doing fine, Dave.

I've posted this chart before but it has all the data you need to cut threads. If you aren't clear on how to use it, let me know.

 

[DavidR8]

Thanks Mike, I appreciate both the vote of confidence and the chart!


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[mmcmdl]

If you weren't on the other side of the world I would ship you all you need !

 

[cathead]

A lot of the time I use a digital calipers to measure the outside diameter of an existing bolt thread. That gives
you pretty close to the diameter needed for using a die. The best way I have found to get the die cutting
perfectly straight is to use a collet in the lathe and set the die against my tool post that has been squared
against the chuck for being true. I generally manually turn the die by hand and push the carriage slightly towards the
headstock. On long threads I will sometimes power the lathe at a low speed and hold the die using the die holder or
a big Crescent if I am using large hex dies. For critical work, I will consult with my favorite Machinery's Handbook
and definitely use the above procedure and use my best cutting oil.

 

[Mini Cooper S]

What cathead said, another way is turning the straight section to the size you need and then use the existing threads as a starting guide for chasing the threads. That way you don't have to worry about getting the die started straight. Once you have your bolt threaded, cut off to the length that you want.
Richard

 

[DavidR8]

I'm going to give this another try tonight and see how I fare.
Thanks for all the excellent advice. As always H-M members to the rescue!

 

[addertooth]

I would be tempted to start with a 5/8ths bolt, and turn it down to the desired major diameter. This way, I don't have to manufacture the cap end. I would not start with a coarser thread bolt of the same size, as the bottoms of the coarse threads run deeper than the bottom of the finer threads. A 9/16th bolt might work, depending upon the Grade the bolt was as well. In my local market 5/8ths bolts are much easier to find.

 

[ErichKeane]

FWIW, THIS: http://theoreticalmachinist.com/Threads_UnifiedImperial.aspx is my favorite thread calculator. It has a bunch of builtin sizes, plus calculates out custom sizes!

 

[NC Rick]

Thanks Mike, feel a bit silly having read the wrong column


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Dave,
I am getting better about reigning in my frustration when I make mistakes and try to be joyful from the opportunity to learn. This has brought me much joyfulness since I have SO MANY learning opportunities, many of them with some repetition to make my lesson plans stick in my head ever so much better.