blade straitening

[Deweyknives]

I forged a 10" bowie out of 1084 a while back. After a trip across the belt, I could see some twist from mid-blade to tip, more than I wanted to try to grind but not much. So I torch heated it and bumped it twice with a small hammer and it about straitened itsself.

Could this have been done cold in the vise w/o ill-affect? Or would it just warp during HT?

 

[A C Richards]

It may have been able to be done cold but a twist may need a little more help. I would do a couple of normalizing heats after straightening just to be safe. This will help out during the HT in keeping it straight.

 

[Deweyknives]

I usually normalize after forging and again before HT anyhow. Might have missed this one after forging? Gave it a nice even heat so it had a 'mid-build normalize' anyhow!

So, how much can you manipulate an unhardened [cold] blade before you create a problem? What's happening at grain structure level? Lets use a narrow hidden tang for example. If you sight down the blade and see the tang is 10* off, do you just stick it in the vise and give it a tweek and forget it? In a high stress area, will that ever create a problem?

Remember,simple steel and small adjustments. Not 30* of movement.

 

[A C Richards]

If you are talking an area that will not be HT'd then it is not a big deal. The minor moving does not seem to be a problem. I will straighten cold right up to ht. Then just before I do my austenizing quench I will do another thermo-cycle or two just to be safe. After HT do not do any adjustments until after tempering. I then temper one more time after any required straightening is done.

 

[Deweyknives]

Thanks Chuck. I've always done adjustments hot. Just figured it was safer. Even w/ ground blades, I normalize untill there's no warpage. Then I check again right out of the quench, while still hot. Anything out of wack beyond that goes back to the HT pile.

I'm not sure if I can twist & pry on a cold blade, but I'll give it a try. Save some time & fuel. It just does'nt feel right!