And finally we come to the main part of the machine shops job, honing the
cylinder walls. It will do two things. First it will bring the cylinder
walls to the matching diameter of the new pistons. Second it will leave a
cross hatch pattern of light scratches, to keep oil on the walls and
prevent metal on metal scraping. A dial bore gauge is used to bring it to
the exact spec needed within 1/10,000th of an inch.