Heat on the blade

[panch0]

Ok this is the first time this has happened to me and it was just carelessness on my part. I was using a 400 grit belt to get my edge bevels before I used the paper wheels to put the final edge. I left it on one spot too long and the edge turned brown. The brown coloration was only 1/32 or less ...very small and was about 1/2 inch in length. I continues till I had a razor edge and started to shave of chunks of a 2x4. After about 25 cuts I looked at the edge under the light and I could see the burned area had lost all sharpness. My question is how far would the damage be. Would I be able to carefully remove 1/16 of an inch fix up the flat grind. Is the damage just local to where the browning or is it further up the blade in the area that did not show browning? Am I making sense here? Thanks guys.

edit: The blade was heat treated

-frank

 

[CDHumiston]

You're making sense to me. In my experience you just damaged that one small spot that got very hot and burned. I would guess only the browned area is damaged. You should be able to carefully gring it off and still get an edge.

 

[Darrin Sanders]

Although I am interested, I can't say how much damage was done. But I would try regrinding the bevels with a sharp 120 belt, then clean up with a 400. That's how i always grind my final bevels, and that is why I do it that way, to avoid overheating. Let us know how it turns out.

 

[Frank Niro]

I go 120, 220, and 400, and I 'm sure if you go over the edge starting with the 120 it will come out as it should. Frank

 

[silver_pilate]

Frank, I agree with Darrin. I used to use a sharp 400 grit to establish my final edge bevel, but I found that it took just too ridiculously long in order to not build up too much heat. I started establishing edge bevels with a sharp 150 just to raise a rough burr along the entire edge, then switch to a sharp 400 followed by a dull 800 with white compound, raising a new burr with each successive belt.

By the way, I'd do as you suggested and adjust your profile slightly and rework the flat grinds a bit. I'm guessing the heat damage is only as extensive as the thin edge. Regrind and then sharpen and retest to see what you think.

--nathan