So hours into a blade, I cracked it during heat treat.

[sharxbyte]

I've looked for hours around the web, and I know this was a stupid error on my part (wrong kind of heat treat on mystery spring steel, too lazy/hurried to test on a few scraps). The crack actually took place about 8 months ago, and I'm considering revisiting the blade. I don't want to weld or braze the crack shut (or at least not until I ensure that it won't propagate) but I had an idea.

For glass, you can sometimes stop a crack by drilling a hole at the termination. I was thinking by using a large enough bit, I might catch even the microscopic end of the crack, and then either cut/grind/weld/fill/heat treat it and have a mostly serviceable blade, and if that fails, at least I still have a nice looking shelf knife. Unfortunately, I already made a sheath for it (before heat treat) but I guess I can re-make a similar enough blade to fit if all else fails.

has anyone else used this method on a blade? what degree of success if any?

Thanks!

[ThomasPowers]

Put it in the oops pile and get on to making a good one.  Knife blades undergo too much flex for a repair to work well.

Now if the crack was in the tang you could weld it up using proper technique for high carbon steel and re heat treat the entire knife.