Can I use an 8" grinding wheel and a 10", together?

[Frederick Skelly]

I've been toying with getting a Tormek T7 because it has a steel body, a 10" stone and the accessories I want for only about $50 more than a comparably equipped T4. (No, I dont "need" it - I have a bevy of good stones and I'm reasonably profient with them. But it crossed my mind to buy one.)

Can I set my plane iron's bevel angle on an 8" low speed grinder and then do the actual sharpening on the 10" Tormek? My gut says that - while this will work - it's a dumb idea. Both wheels need to be pretty close in diameter to do it right.

Are any of you using grinding wheels of two different diameters in successive sharpening operations? Does it work or is it a poor solution?

Thanks for indulging my crazy idea.
Fred

[John K Jordan]

...Can I set my plane iron's bevel angle on an 8" low speed grinder and then do the actual sharpening on the 10" Tormek? My gut says that - while this will work - it's a dumb idea. Both wheels need to be pretty close in diameter to do it right.

Fred, I often shape some of my lathe tool bevels with 8" CBN wheels then use the 10" Tormek with a 1200 grit CBN wheel to sharpen. I do this since shaping a tool is pretty slow on the Tormek at 1200 grit but very fast with the 1/2 speed bench grinders with coarser wheels. (I use 80, 220, and 600 grit CBN wheels on the bench grinders)

You might do the math. I did the calculation once to figure the arc height (difference between flat and the concave grind) for the width of the bevel on my 3/8" spindle gouges and found that the difference between 8" and 10" was very small. It only takes me a few seconds on the 1200 grit wheel to make up the difference to create a precise concave bevel at the 10" radius. The difference would be even less for a plane iron with a bevel narrower than the tools I sharpen, at least the plane irons I'm familiar with. Caveat, I don't sharpen plane irons with the Tormek. I use the Tormek for lathe spindle gouges, bowl gouges, some small scrapers, and a few other tools.

It does, of course, take longer to go from 8" to 10" with an extremely wide bevel, such as that on a typical diamond profile parting tool.

JKJ

[Frederick Skelly]

Thanks John!