Threading Stainless Hidden Tang

[Sam Wilson]

I have a question about threading a tang on a hidden tang knife. Going to do one in stainless and want to thread the end of the tang for a buttplate.

My only concern is breaking the tang at the threads. I don't know if threading pre-heat treat will introduce stress risers, and if the pommel plate is beat on while being used as a completed knife it may be enough to snap it.

If it were carbon steel I would just draw it back after heat treat and then thread it. But I don't believe that will work with CPM 154/440C.

Any thoughts or ideas?

Thank you,
Sam

 

[S.Alexander]

Someone would really have to wail on it to break it. That would be abusing the knife beyond what it's designed for.

If the handle is epoxied in place, and the butt plate is screwed on, then I don't see how the threads would break.

If you're still concerned about it, then you could build one and test it out.

 

[Sam Wilson]

Thank you for replying. I agree with you. I am concerned more with the stress risers aspect than the strength of the design, in this case.

I don't know if cutting threads prior to heat treat introduces another potential mode of failure as opposed to cutting them after. That is the part that concerns me.

 

[kc custom]

I would bet that pretty much any threads cut on stainless that can be hardened is done before
heat treating. Would be some impressive dies if they worked after heat treat. You could slot the
tang and silver braze threaded rod into it after heat treat
Ken.

 

[Sam Wilson]

That is how I usually do them, I wanted to do it another way this time. I'm sure you're right about the threads, but wanted to get some different perspectives. Thanks for the reply.

Sam

 

[Darrin Sanders]

I do them that way all the time and I've never had a problem.

 

[Sam Wilson]

What way? You thread stainless tangs prior to heat treat?

 

[Stacy E. Apelt - Bladesmith]

Thread before HT.

You are over-thinking this. In stainless, stress risers are not as big an issue as the faster quenching carbon steels. The steel has plenty of time to even out stresses in the much slower and less stressed cooling curve. It isn't anything like the sphincter clenching, terrifyingly rapid conversion to martensite in high carbon steel.

 

[jdm61]

Toni Oostendorp,one of the Dutch makers, posted a stainless version of one of his standard knives the other day and peened the end of the tang to hold on the buttcap just like he does with his carbon blades. He said that he tempered back the end of the tang after HT.

 

[Stacy E. Apelt - Bladesmith]

Yes, heating the tang to about 1000F with a torch or heat gun will lower the temper. Don't let it get red, or it will re-harden as it cools.

1000F is called black heat. The steel will show a sudden lack of reflection and get darker looking. Just past 1000, right around 1100-1200, it will start to get a very dull red glow. It is barely perceptible in bright light, but will be visible in subdued light. That is as high as you can take it safely. Try and hold the tang at this temp for a few minutes if possible.

 

[Sam Wilson]

Thank you, that's what I was looking for.

 

[Hengelo_77]

Here's an other way to get thread