Help with through tang threads

Phil705

Phil705

Basic Member
Joined
Aug 23, 2007
Messages
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I screwed up. I am working with 3/32" A2. I cut out a through-tang blank, did some file work, then tried to thread the tang for the holder nut. All this is before HT. In doing so, I twisted the threaded part, and in trying to straighten it, it broke off.

1. Should I have threaded it before HT or after?

2. Could I salvage this by welding a bolt in place of the broken one? Any suggestions on how? Will stainless bolt weld to A2 or should I find a steel bolt? Would I do this before or after HT?

Could not find any tutorials on this.

Phil705
Winthrop WA
 
i cut the tang off a knife only to change my mind and came up with a fix that might work for you. pm me with your email addy and i'll send you some picks.
 
You have to thread before HT. Perhaps your starting diameter may have been a little oversize? Did you use a tapping lubricant? Moly grease works, WD40 doesn't.

Yes, you can weld a stainless or nonstainless bolt to A2. You can do it before or after HT, but I'd do it before. The HAZ will be brittle, so you might want to heat it after welding to 900 deg or so with a torch to prevent cracking.

Generally, you're supposed to preheat before welding high carbon (reduces cracking of nonductile metal by reducing dimensional deltas), especially something that air hardens, but I wouldn't bother for your application.

FYI, I've welded to A2, D2 and O1 without problems, even on stamping dies subjected to shock. The stuff welds fine. Some folks say stainless filler rod works better.

An alternative to welding would be to braze.
 
Phil705 said:
I screwed up. I am working with 3/32" A2. I cut out a through-tang blank, did some file work, then tried to thread the tang for the holder nut. All this is before HT. In doing so, I twisted the threaded part, and in trying to straighten it, it broke off.

1. Should I have threaded it before HT or after?

2. Could I salvage this by welding a bolt in place of the broken one? Any suggestions on how? Will stainless bolt weld to A2 or should I find a steel bolt? Would I do this before or after HT?

Could not find any tutorials on this.

Phil705
Winthrop WA
Click to expand...

Phil705,
Grind the rear of the tang (square it up) drill a 1/4 in hole in it (center punch for hole at .400 from rear of tang) Send the blade out for HT & email me when you get it back. I have taken some pictures of the process that I use & will share them with you.
Randy
 
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