Kepple- my grinder doesn't have the ability to really regulate the infeed speed as much as I would like so that I can really "plug" up the screens by forcing the material that is being ground to stay in the grinding chamber for a longer period of time. I'm already grinding through a 1 1/2" screen, and I don't really want to go any smaller for a variety of reasons.
Also, not all wood mixes require me to do a double grind. We technically buy in primary ground wood to grind again and color-I'm not grinding straight from logs, so my "primary grind" is technically a second grind already. The new, cleaner, round wood, all-wood mix we are working with goes through the grinder almost twice as fast as wood mixes we have used in the past. So we tried "triple grinding" our wood this time around and found that with the type of wood we are using, I can get a better product, with less wear on the grinder, and for less money by sticking with the wood mix we are using.
How's the recycling business going? Haven't heard from you in awhile- I assume things are keeping you busy down your way.