Questions about contact wheel hardness

[rtj1981]

I'm getting ready to order a contact wheel to convert my surface grinder to run belts and am a bit confused about what hardness I want. I've read that you want close to 100 durometer but in Sun-ray's website they list hardness's any where from 60a to 70d, which they say is a hard a a golf ball. My question is what scale is everybody talking about when they say 100 durometers, is it the "a" scale or should I just get the wheel as hard as I can?

 

[hathegkla]

75D is fairly hard but still has a tiny bit of give to it (like a skateboard wheel). 100D would be very hard. I actually don't know what the durometer on my contact wheel is but I'm guessing its around 50-60D.

but if they just say 100 durometer its not really a complete answer. A and D are 2 different scales. A being softer.

a softer wheel will have more give and allows some of the grit to be pushed into the wheel surface resulting in more shallow cuts. I've heard that very soft wheels can actually buff the surface, never tried one though.

 

[12345678910]

I'm getting ready to order a contact wheel to convert my surface grinder to run belts and am a bit confused about what hardness I want. I've read that you want close to 100 durometer but in Sun-ray's website they list hardness's any where from 60a to 70d, which they say is a hard a a golf ball. My question is what scale is everybody talking about when they say 100 durometers, is it the "a" scale or should I just get the wheel as hard as I can?

"A" Scale is the typical scale

I have also seen info on surface grinder conversion at 90 to 100 Durometer A

 

[hathegkla]

"A" Scale is the typical scale

I have also seen info on surface grinder conversion at 90 to 100 Durometer A

durometer scale is a bit confusing, "A" scale and "D" scale overlap. 100A would be close to 60D so 100A would probably be a good choice for a contact wheel.

 

[Justin.Mercier]

I've read that 70D is a good 'hard' wheel to use for the likes of a serrated wheel / heavy grinding wheel, and that 50D is a good 'soft' wheel for finishing grits. So if 100A is actually like 60D then that would be a good hardness. (or softness)