Overgrind. What is it? How does someone do it? And more importantly how do I avoid it?

[greasedbullet]

So I was just looking up the moritaka problem with over-grinds and it got me a little paranoid. How do I know I am not over-grinding the knives that I make? I haven't seen any problems or anything. I guess I am just curious what are the signs that you are creating an overground knife as you are grinding and is there any way of correcting it if you are still mid grinding process?

Thanks,
Mike

[berko]

http://www.kitchenknifeforums.com/sh...ow-long/page10

post #93

[JohnnyChance]

Hold the knife parallel to the ground and up to the light. Looking down the blade as you rotate it slightly you should be able to see waves, dips, variances, etc. I would assume you have some as grinding perfectly even convex bevels the entire length of the blade certainly can be tricky. Not saying they would be or are a problem, but there will probably be some variation in there. Sometimes catching the edge of the belt and you'll end up with a line, some are wide and shallow, others can be deep into the blade. How deep they are is the determining factor whether they will be a problem or not. If they go deeper into the blade than your centerline (where you edge is) then that is a problem. Even if it is fine at the moment, once you sharpen and you hit that low spot, it will open up and you will have a much smaller edge bevel at that spot or have trouble putting an edge on it at all. If your dips are shallow and do not go to the centerline, then normal thinning as you sharpen will even them out and even if they stay they will only be cosmetic. Keep checking the blade while you are grinding before small areas become big problems. Also, doing your final thinning by hand on a course stone can help you even out small holes and avoid problems.

[greasedbullet]

Oh. That seems much more difficult to do than I expected.
Thanks for the info.

[JohnnyChance]

You should only encounter the problem if A) you are running a mass production operation with unskilled or uncaring laborers, B) you are forging your knives to near final thickness and let the hammer wander/spend too much time on the area at/behind the edge, C) you are trying to your knives super thin at the edge like we like...and it just gets away from you. Like I said before, if you are worried about it, finish on the stones.

[greasedbullet]

Thanks a lot.

[Dave Martell]

You should only encounter the problem if A) you are running a mass production operation with unskilled or uncaring laborers, B) you are forging your knives to near final thickness and let the hammer wander/spend too much time on the area at/behind the edge, C) you are trying to your knives super thin at the edge like we like...and it just gets away from you. Like I said before, if you are worried about it, finish on the stones.

Perfect explanation

[Dave Martell]

Oh. That seems much more difficult to do than I expected.

It's actually very easy to do when the blade gets thin at the edge. This is high end kitchen knife problem.