Don't get wrapped up in the single cut burrs for aluminum, double cut burrs for cast iron BS. Single cuts burrs dig and bounce and if used especially by someone inexperienced become dull quickly and if its a long shaft, BEND. I use a foot controller to control my grinder speed and when done with a double cut burr doesn't even need sanding rolls to clean up. Bottom line is we aren't doing it for a customer to push out the door so "slow down"



Porting tools 005_zpsjgwy0cgl by John Cadamore, on Flickr


Porting tools 002_zps56hn5i69 by John Cadamore, on Flickr


Porting tools 004_zpslw8s6tvt by John Cadamore, on Flickr