The Home Machinist!

I've heard of people using Elmer's glue. Let it dry then peel it off.

I have always wondered this but have never seen it addressed. If you are grinding a HSS tool and you overheat it so that it changes color, how far do you need to grind it to get to good metal again? Is it just the skin that is affected or does it go deeper down than that?

Thanks,

Kevin