Porting Tools

Die grinders

Die grinders come in 2 main sizes, 1/8" and 1/4" inch. Dremels are 1/8". Only 1/4" are effective on heads, intakes, exhaust, etc. The 1/8" ones are ok for inside the turbo. Note that most mfgs have 1/8" collets for their 1/4" die grinders as an accessory. Die grinders come in 2 types, air powered and electric. The air ones require substantial air (2+ HP compressor) and can be quite powerfull. The pros use Dumore, they free wheel at 15,000 but under load spins at 9000. They are a bit expensive new. You can call them at (608)847-6420 for a catalog.

 Makita 1/4" electric, 3 amp $ 90  good quality, fine for home use
 DeWalt 1/4" electric, 3 amp $ 120  
 Milwaukee electric, 5 amp $ 180  pro tool, use caution, VERY POWERFUL


There are 2 main typse of cutters; high speed steel (HSS) for aluminum or short life on steel (including cast iron) and carbide for aluminuum or long life on steel and cast iron. The cutters come in many sizes and shapes and "teeth per inch". For aluminum I get the really coarse ones and the medium for steels and cast iron.

Suppliers: Fullerton tool co.. Enco, basically machine shop supply places. Expect to pay $40 for a 5/8" carbide.


There are many types; sanding rolls, cross buffs, bore polishers, scotchbrite in various configurtions. For our uses get 60 grit sanding rolls in 3/4 x 1 1/2 with 1/8 mandral. Use a 1/4 by 1/8 that is about3" long (a 6" long one is a good addition). Use 3M sanding rolls, cheapies don't last.