Edge too thin before HT? Help?

[onebagnomad]

I've put alot of time into my current knife, I'm doing some final sanding before HT and I think I overdid it during the draw filing stage. The edge face has become thin to the point of almost being an actual edge. I'm using 1/8" 1080 and heat treating with a couple of torches and a canola oil quench. Am I screwed? Am I going to end up with a piece of scrap when I HT this thing? What temp should I have the oil at to minimize possible damage? Are there any precautions I can take to avert disaster? The blade is 3" long with a scandi grind, if that is a factor. As I've said, this has been a project of mine for a few weeks now. It's my 3rd and the first knife I feel proud to say I made. I know I'm working with a less than ideal process, but it's what I have at the moment. I'd hate to lose it during the final stages. Any advice is greatly appreciated please.

 

[J. Doyle]

You could thicken the edge by sanding or filing on the edge to get into the thicker material just behing the edge. this would only change your profile a little bit.

You will probably still be okay to quench then. It might warp a little but then you'll have to straighten it.

 

[Nathan the Machinist]

A short scandi is probably going to tolerate that better than anything. My suggestion would be to apply the heat on both sides of the blade very evenly, bring it up to temp gradually, and keep the flame off the very edge, which will tend to over heat.

Canola oil is slower than a real quench oil, so your quench speed isn't going to be too severe (in fact, you're probably going to get some pearlite, oh well) but it has nothing in it to control vapor jackets, which can cause warping. With that in mind - I'd want the oil heated enough to be thin (120?), I'd do a full quench and I'd agitate well during the quench (not side to side, but like you're chopping with it).

Once it stops boiling (perhaps 10 seconds) you can pull it out and try to straighten any waves in the edge before it finishes cooling.

You're probably going to get a bit of a wavy edge. That can often be ground out after HT.

My .02... This is not my area of expertise...

 

[cotdt]

When you sharpen the knife after HT, you're going to remove that metal anyway. I wouldn't worry about it. I've done 1084 and it does not crack easily during the quench, especially not in canola oil.

 

[onebagnomad]

Thank you guys for all of your input, I'm very happy to say that the blade made it through heat treatment in one piece. I ended up doing as Nathan suggested and it went very well. Thanks again.