I've been working on an engine cylinder, 1" bore x almost 3" inside length. The head is integral to the cylinder so is not removeable. I thought I had the cylinder finished, but today measured a slight taper. The bore on the head end of the cylinder was about .002" less than the outboard end.
Not being very familiar with lapping and not having a hone of the right diameter, I came up with the following:
It's made from a length of brass pipe nipple and the last 1.25" is turned to a tad less than the cylinder diameter. There is a slight reduction in diameter on the back end so only the last 1.25" does any work. I then cut 4 slits in the tube and sprung the ends out so the end would bear against the cylinder. I mounted the pipe in my lathe, smeared clover lapping compound into the cylinder and set to lapping the cylinder. Since the pipe is sprung outward it exerts more pressure on the end than toward the middle. Within just a few minutes of lapping, I was able to the get rid of the taper and achieve a very nice finish on the cylinder wall.
Chuck
