Department of automobile engineering
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Figure 4 HONING The cylinders must be honed a minimum of 0.002 inch after boring to cut below the rough surface and provide an adequate finish. Honing leaves a plateau surface that can support the oil film for the rings and piston skirt. This plateau surface is achieved by first using a coarse stone followed by a smooth stone to achieve the desired surface. The process of using a coarse and fine stone is called plateau honing. Its honing stones are held in a rigid fixture with an expanding mechanism to control the size of the hone. The sizing hone can be used to straighten the cylinder taper by honing the lower cylinder diameter more than the upper diameter. As it rotates, the sizing hone only cuts the high spots so that cylinder out-of-round is also reduced. The cylinder wall surface finish is about the same when the cylinder is refinished with either type of hone. See figure. The hone is stroked up and down in the cylinder as it rotates. This produces a cross-hatch finish on the cylinder wall. A typical honed cylinder is pictured in figure. The angle of the crosshatch should be between 40 and 60 degrees. Higher angles are produced when the hone is stroked more rapidly in the cylinder. 
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