I have not found that lapping will remove pits visible to the naked eye.
MAKING THE CUTTER FOR THE GROOVES
Here is how I re-cut the grooves and lands with cutters inset into the lead lap. The cutter for the grooves must be exactly the width of the grooves and the top where teeth will be filed must closely match the profile of the grooves. One has to be very good at fabricating and filing to make the cutters. I make mine from spring steel. My cutters are 1.5” long and about .100” to .125” in thickness. I measure the groove width on the lap I just cast. Making the cutter is the most important and hardest part. Use your micrometer or calipers, square, and magnification. Must have uniform height and width within 0.001”. Then I mark the top of the cutter with dykem and cut the teeth with a triangular file. I normally cut about ten teeth per inch. Two types of teeth can be cut. One is trilateral triangle in shape, like pyramids. These scrape in both directions. I know folks who like them. I cut teeth with a vertical front face and a sloping back edge. Look at a wood saw blade versus a file. I file these using a very fine, small triangular file. After filing the teeth and grooves to catch the swarf, I double check they are all sharp and same height. Then I harden the cutter and temper it fur an hour at 425F in a tin can filled with sand in the kitchen oven.
If interested, next installment is how to set the cutter into the lead lap.
MAKING THE CUTTER FOR THE GROOVES
Here is how I re-cut the grooves and lands with cutters inset into the lead lap. The cutter for the grooves must be exactly the width of the grooves and the top where teeth will be filed must closely match the profile of the grooves. One has to be very good at fabricating and filing to make the cutters. I make mine from spring steel. My cutters are 1.5” long and about .100” to .125” in thickness. I measure the groove width on the lap I just cast. Making the cutter is the most important and hardest part. Use your micrometer or calipers, square, and magnification. Must have uniform height and width within 0.001”. Then I mark the top of the cutter with dykem and cut the teeth with a triangular file. I normally cut about ten teeth per inch. Two types of teeth can be cut. One is trilateral triangle in shape, like pyramids. These scrape in both directions. I know folks who like them. I cut teeth with a vertical front face and a sloping back edge. Look at a wood saw blade versus a file. I file these using a very fine, small triangular file. After filing the teeth and grooves to catch the swarf, I double check they are all sharp and same height. Then I harden the cutter and temper it fur an hour at 425F in a tin can filled with sand in the kitchen oven.
If interested, next installment is how to set the cutter into the lead lap.
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