I have need, from time to time, to replace small plastic fiberoptic rods used for gun sights. The factory rods have a small rivet-type head on each end of the rod for retention. Mulling it over, I figure that maybe using friction and spinning the head on would work. To do that, I'd need a highly polished spherical cavity on my spinner. I've not had great success producing same in the past, this would be probably between 2 and 4mm across. I've come up with a methodology that will probably work. I'd either make up a D-bit with a hemispherical end of the proper radius(probably 3-4x the radius of the fiberoptic rod) or use a carbide burr in a micro die grinder/Foredom handpiece to produce the shallow cavity in the end of the tool. I'd then use a tungsten carbide ball and use that in conjunction with a bench vise or press to produce the surface finsh I want. Lee uses something similar to produce lead ball molds for blackpowder shooting. I'm considering using something like 1/4" brass/bronze rod that I've got sitting around for tool stock and using a pneumatic micro die grinder for driving the tool after it's made becuase it can be throttled way down. If I end up making up an alignment jig, it's would be simple to use a V-block mount on the cylindrical die grinder body to mount it to the jig. Anybody ever done something similar?
Stan