A Good Example

[btrwtr]

Are you going to weld and re-drill the pivot hole or will you just drill it slightly oversize to get rid of the out of round and use a larger pin?

Steady as she goes on this one.

Steady as she goes is right. First I'll trace out the exact shape and size of the remaining intact piece of tang to give me a guide as I regrind and normally there is no problem with the hole. TIG welding uses a rod (in this case) that is about 1/16" and the guy that does my welding can add the needed metal without filling the hole. Its what he does for a living and he's gotten very good at it. My biggest concerns will likely be grinding the blade back to 1 or 2 thousandths less than the width of the backspring and making sure the backspring grinding is as seamless as possible. After that, it should be a straight-forward reassembly since we're using the original handle material.

If the hole were to see some added metal, I'd take a small Dremel attachment (after grinding to the correct width) and try to bring the hole back to match the other blade in the knife. I'm not a fan of enlarging the pin size except as a last resort. It is a good option that is nice to have as a fall-back should problems arise, but I try to save it if I can.

Have you or your welder ever used a heat absorption paste to keep the heat generated from the welding process from ruining the blade temper?

[Elvis]

Have you or your welder ever used a heat absorption paste to keep the heat generated from the welding process from ruining the blade temper?

No. He clamps the piece in a large vise (jaws are each abour 2"x10") so that only the tang end or the tip of the backspring are showing. The vise seems to work well as a heat-sink for this purpose.

[btrwtr]

I've always referred to the small tabs of metal that develop as "ears".
Not sure if there is another term but that's what they look like to me so that is what I call them. Any other terms you use or suggestions to describe?

Wayne

[Elvis]

I've always referred to the small tabs of metal that develop as "ears".
Not sure if there is another term but that's what they look like to me so that is what I call them. Any other terms you use or suggestions to describe?

Wayne

I never thought about giving them a name, but "ears" is probably as fitting as any. I don't recall if I mentioned this or not, but I lay the blade with the "ear' down and trace the outline to use as a guide for regrinding after the welding is done.

[Huck Finn]

:: A little knowledge is a dangerous thing: mass confusion; I'm a rocket scientest, Merry-go-rounds make me me feel nausea.

[GClaxon]

Excellent post!! I have blade tangs welded all the time for customers at my shop. The only way to save a knife when replacement blades can't be found, especially harder to find brands.

[millern]

Great photos! Similarly,I have used a 90amp Harbor Freight wire feed welder to add a tiny spot of material to the tang of a leverlock switchblade to close the worn sear hole. I then re- file the hole “open” just enough to catch the sear. This can address the problem of worn switchblade knives when the tip of the blade “peeks” out of the handle when closed. Using a vice grip or bench vise seems to provide an adequate heat sink during the spot-welding. I have notice very little tang discoloration from heat.

[Elvis]

Millern,
Usually that slight discoloration can be buffed out if you have a buffer and some buffing rouge.

[1967redrider]

This is a great old thread. How much fidgeting do you have to do to make a blade look like that.

[Bill DeShivs]

looking good Bob.

I've tried JB weld and Bob is right, it peels right off the tang when the action is worked for the first time. I have used silver solder to make tang repairs but even it will wear as it is softer than the backspring steel. Weld is about the only way to go. Now, that said. I have a theory, as I have yet to actually try it but I see no reason it wouldn't work. Cut the tang down a lot and dovetail in a larger piece of steel and solder it in place (like the old Robeson mastercraft series with the bronze tang inserts) and shape to fit. I see no reason why it wouldn't work but it would be very time consuming, having someone lay a bead of weld on the worn areas would be much more realistic.

One thing I am curious about though is the temper, how is it affected by the weld? I worked on one switchblade that a guy welded in a chip in the tang that was preventing it from locking open. When I worked it down to fit it was VERY hard, like freshly quenched steel that hadn't even been drawn back. I always wondered if he quenched it in something immediately after completing the weld. The metal was all down to a bare finish almost like a bead blast look. maybe he dunked it in a pickling solution to remove the scale after the weld was complete?

When we laser weld small areas, we use high carbon jeweler's saw blades as filler. When doing the welding, the steel is heated, but cools quickly because of the small surface area. I have to use diamond files to dress the welded areas- unless I temper the entire piece.

If the piece to be welded can't be that hard, we use low carbon steel "binding wire" as filler. Binding wire is used to bind pieces of jewelry together for welding or hard-soldering.

[SwedgeHead]

A lathe comes to mind, it would be micro-meticulous work but I am wondering (to myself) if one could fashion a bushing for something like this too. Just another approach... I've never attempted something that small.