The machine can grind single cams or multiple-cam camshafts. My machine was built as a means to an end using mostly materials from my scrap box. I used my old Unimat SL lathe to provide the precise X and Y movements needed for the grinding wheel. I suspect that in most cases the design will need to be adapted to suit available materials and equipment. I am therefore offering detailed drawings for the swing arm, which forms the main part of the machine, but I will describe the base and the use of the Unimat in less detail, on the assumption that prospective builders will modify these elements. I was working on a design and build project for a series of miniature four-stroke IC engines and was contemplating the best way to machine the cams. The project, ongoing at the time of writing, consisted of four single cylinder engines and one inline four with alternative single and double overhead camshafts, giving a total of 24 cams to be made, photo 2. Two methods for making miniature cams are generally cited. The first involves mounting the cam blank onto a dividing head of some type and milling the cam profile with the end teeth of an end mill. The approach is to rotate the cam blank in small increments, taking a cut of the appropriate depth with the end mill at each increment, setting the depth with the Z axis feed. The Z axis position must be calculated for each rotational increment. The resulting facets are then filed away by hand. The second approach is to use a jig in the lathe which presents the cam blank to the cutting tool in such a way as to allow the cam flanks to be turned separately, further work being required to form the base circle and nose profiles.
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