Cyclones and Pulleys

Ballendo is right, Wood magazine did publish a cyclone plan a while
back. You can download this plan for about $10.00; I forget the url
but if you hunt a little you'll find it. I bought the plan and found
it helpful--just the suggestion (and part number) for using a diesel
engine air filter cartridge on the output side is worth the price of
admission. There are patterns for the sheet metal parts, etc.

I was going to build my own cyclone but found a great deal on ebay
instead. Also check ebay for great deals on blowers for cyclones;
$100 will buy you a lot of fan. In fact quite a bit of Torit
equipment comes up on ebay--$250 will buy you a $2500 system ready to
go. Reliable Tool in LA frequently has areospace surplus dust
collection / air filtration units.

Re pulleys: If you want to do some of the work, you can buy a whole
salami of timing pulley material (has the proper cross section) and
cut the slices yourself. Several vendors sell this raw stock.

In fact, finished toothed pulleys are so expensive that (if you have
a mill) another option is to buy a used index head and tailstock
($250-$350) and make your own salami.