You guys kill me when you state that a cross-cut burr will clog to fast. For the new-be grinder a double-cut burr is 10 times more forgiving as they won't jump around. slow your burr down and use the items listed above to cool your burr. I probably do about 80% of my aluminum porting with a long shank (6 inch) double cut burr and when finished with my own stuff don't even need a sanding roll to finish the job. Customers like shinny so they get the sanding roll treatment.