11-Mar-08 Rough machining the Drive Rod. Castings are a pain for work with, especially something like this where the surface you want to clamp on is also the suface you want to machine. And all the dimensions are around the centerline of the part, but like all castings, things are bent, warped or twisted. Clamping on the 'webbed' portion of the rod causes the ends to flex (see shims under part to compensate). Probably a better method would have been to drill a through-hole to screw the part to the table and machined around the screw. See connecting rods pictures.