Catt22, I agree with you. It is difficult to go too slow, especially with the easily available parts out there. Trying to get a 15" pulley ( or larger ) and the room for it is difficult. But it is easier to go too fast. The real proof is in the brewhouse efficiency and astringency of the final product. If you aren't able to slow things down, tempering your grain is a good idea, it reduces the damage done, and also should reduce your dust. At least it helps some. Here in WI we see more variations during 'brewing season' due to the temperature and humidity fluctuations. Last week it was 20% RH, this week its 80%. This affects the friability of grain. And if you really need the acid test, you can sieve your grains through screens and measure the result, like the big boys 'supposedly' do.