I'm now up to vol.3 of David Gingery's metal shop series, the one on how to make your own metal shaper. He has a few comments in two places about how to make your own arbors. The ones he's describing are about 6 inches long and his comments are not very detailed. For example, on p.13, he writes: "It is impossible to drill a precise center in each end of a shaft, so you must begin with over-size stock to make your arbors. The diameter will then be concentric with the centers, and you can do accurate work on anything that you mount on the arbors."
I think what he means is this: (1) You can't to take a cylindrical rod the size you want and expect to drill a dimple at each end accurately enough that when the rod is mounted on a lathe using the two dimples, the axis of rotation will coincide with the axis of the cylinder. (2) Therefore, you have to take a rod which is too big, do your best to drill the holes you want, and then use the holes you drilled to mount the rod on a lathe and turn the rod until you have it down to the desired diameter.
Is that what he means?
Ignorantly, Allan Adler snipped-for-privacy@zurich.ai.mit.edu
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