Ice Water

I was at forum member The Topher's house some time ago and he was restoring some old blades. A bit of grinding here and there and polishing with the Dremel. He had a glass of water on the workbench with ice cubes. Every so often he would dip the blade in the water.

He told me that he could feel the heat in the blade and when it reached a certain point he would dip it and cool it off. This may be general knowledge amongst you gentlemen that do restores but in case it hasn't been brought up lately I just thought I would mention it. :tu

I also use a glass of ice cold water while re-working a blade to quench it. Heat can cause the temper to be lost from what I understand. Though I have read that that temperature is relatively high. If the blade discolors it most likely has had the temper lost.

I believe that Chris (The Topher) told me it was something like 400 degrees Fahrenheit before the temper was affected ? That would feel a lot hotter then the bare hand could tolerate. Still any heat that began to get noticeable would be due for a quench if I was polishing.

out of paranoia I quench pretty often, I use plain water, no ice. heat disippates very rapidly in water. I find that polishing iwth the dremel creates more heat, faster, than using the grinder.

Red

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Originally Posted by Big Red

out of paranoia I quench pretty often, I use plain water, no ice. heat disippates very rapidly in water. I find that polishing iwth the dremel creates more heat, faster, than using the grinder.

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About half the time I'm cutting/grinding/sanding I have the blade in a vice so I use a spray bottle with water. 2 or 3 little squirts and it's cold again.. and yes, I'm always surprised at how little heat the grinding tools produce compared to the sanding drums or polishing. I figure it's because the grinders sort of "chip" away metal (on a micro level) instead of "rubbing" it off. Kind of like using a wood chipper instead of a hack saw to make mulch.