Can minerals/knot in wood damage A2 blade?

[Tri Hoang]

I had a piece of scrap maple that I used for testing my freshly sharpen blades. In the last day or so, my planes mysteriously leave terrible tracks in wood due to slight dings to their edges...right about the middle part. For a while I could not figure out what caused it. I grabbed another plane and same thing happen. I went through 3 of them. What a puzzle!

Upon closer inspection, the test piece has a little black mark about 1/4" x5/8" in the middle. It does not look like a knot to me. Anyway, I think it causes the dings. I turned to the other side with a freshly sharpened blade...no problem. I still don't know what that mark is but could it be minerals.

Anyway...lesson learned. Next time I know where to look first, and not grab a another plane!

[Luke Townsley]

Nails, fencewire, and other wierd things can grow into a tree.

Here is an interesting post about another way that blade dulling particles became embedded in some trees:
http://www.bridgecitytools.com/blog/...i-wood-victim/

[Todd Burch]

Yes, minerals in wood, (sometimes also known as rocks), can do that.