Well, I don't like using a drill. I like to be able to feel when the compound smoothes out. You caint fell that with a drill, plus, the high speed of the drill slings a lot of the compound out and it doesn't do as effective of a job. ........however, one exhaust valve had a few radial stripes across the face. It was beginning to burn. So, I looked in my stash of slant valves and found another one...although it had a pretty bad case of valve seat recession. SO, I took a 60 grit sandpaper disc stuck the valve stem through it with the grit side facing the valve, stuck the valve in the guide and sammiched the disc between the valve and seat and chucked it up in the drill and had at it. Got the face ground nice and flat and then lapped it in by hand.
