Finishing concave side of spoon blade. | Problem Solving | Forum

Happy New Year,

Flapper wheels have 1/4" shank, they will fit a die grinder or a hand drill, the higher the RPM the better. Flapper wheels come in different grits and diameters. I usually buy 1 1/2" diameter and change them as they wear smaller, this way I get a cross section of a lot of different sizes. Think of the job at hand and the next job that hasn't appeared yet.

For polishing inside an intake or exhaust port, I use a piece of 1/4" round with a saw cut about 1" long in one end. I put a piece of Emery paper (1" wide) through the cut and wind up as much as you can fit in the port. With my die grinder which turns up to about 20,000 rpm, It leaves a very nice finish. The end of the emery paper will self destruct with use and there will be dust and dirt everywhere, but it works very quickly.

I have a Cylinder Head Flow Bench and I have proven many times that a mirror finish inside an intake or exhaust port has 2% less flow than a semi-gloss finish. Think about the eddies of a river, the river flow rides on the eddies, not the banks of the river.

Neil