Curious about heat when grinding

Hi, I've recently been grinding a lot of toolbits after a long hiatus from mach ining. One thing that crops up in my mind - why do some wheels heat the par t so much more than others? The obvious answer is the sharpness of the cutt ing media. When I sand brass on a fresh belt, there is much less heat than with an old belt because presumably the heat goes away with the chips, and there is more cutting and less rubbing. I have various wheels for shaping a nd sharpening, from stone to various hardness of abrasive impregnated rubbe r. It seems the harder the wheel, the more heat. Finer grits heat more, but that seems a smaller issue. Is the answer simply that the surface of the s ofter wheels wear away faster and continually expose fresh abrasive?

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A grinding wheel stays sharp by the surface wearing to expose new abrasive grains and as a secondary effect it tends to keep the surface free of any imbedded metal particles. So a softer wheel of the same size abrasive will generate less heat than a harder one.

It also tends to cut faster :-) And wear faster :-)

Reply to
John B. slocomb

There are lots of reasons.

1) Area of contact (angle, diameter of tool) 2) Grit size (the finer, the hotter, see 1) 3) Pressure used 4) Type of wheel/band (The harder wheels are usually finer grits.) 5) Metal of the bit or insert 6) Time taken to sharpen 7) Sharpness of the media

The answer is "All of the above", and then some.

Reply to
Larry Jaques

Since heat is energy and energy can neither be created no destroyed only transformed, all that heat is being transformed into creatures that will someday demand their place in the evolutionary scale and displace man as the dominant organism on the planet.

And, we have Robobass to thank for the fall of humanity!

Reply to
Tom Gardner

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