You guys and your coarse burrs kill me. I port a lot of heads and rarely use an aluminum coarse cut burr. I mainly use double cut burrs dipped in a WD40 transmission fluid mixture. An aluminum burr cuts, bounces, gouges, and digs compared to a double cut burr. Slow the grinder down to a speed you can handle and grind away
i use course bits all the time for roughing out, although you bring up a good point about slowing the grinder [air or electric] down.
my main fault is ASSuming guys know how to use a grinder.
finishing is always done with a fine burr, then sanding rolls if needed for the finish required.
castings differ from one kind/brand to another, and billet is different yet depending on composition.
your WD40/transmission fluid is a great lube, [i use that combo] and i have found bar soap and stick wax also work good in some instances.
i have also wanted to try a "gritty" type hand cleaner just to see what that would do, but i haven't got around to it.
if a guy hasn't worked with burrs before, it is best to practice on scrap first to see how they work for you, then proceed cautiously until you build up confidence in your work.
make absolutely sure your work piece is held solid by whatever means necessary. it is impossible for you to do any kind of acceptable work if you are chasing the piece around the work bench !
and as always, "practice makes perfect". some have the knack and can whittle away with little effort, while it takes others more time and effort.
remember guys, pittsburger does good work - he has been at it for a while, so listen to his advice.