by Archie » Thu May 26, 2011 11:40 am
Chuck,
It will be a while before I actually get around to cutting the gear, but I enjoy working out the different approaches -- probably more than the actual cutting. As the saying goes: "Life is a journey, not a destination."
Now, from general philosophy to gear philosophy: An extension (done by others, not me) to your one tooth hobbing is to make a rack-shaped cutter referred to as a "pseudo-hob". The cutting teeth are rack shaped, but there is no helix. Cutting time is reduced because more than one tooth is cutting per turn of the arbor. The cutting is spread out over several teeth on the gear blank and if the gashes in the cutter are timed so that they are spaced around the arbor, the different cuts are spaced out over the rotation of the arbor. The pseudo-hob can be made up of a stack of disc-shaped cutters and these can be made on an ordinary lathe if they have only a few cutting edges. I am posting a few graphics showing how to make simple form-relieved cutters without using a relieving attachment.
Archie
P.S.: These are not my graphics, but I believe originated from John Stevenson. (Now, that is a familiar name.)
Chuck,
It will be a while before I actually get around to cutting the gear, but I enjoy working out the different approaches -- probably more than the actual cutting. As the saying goes: "Life is a journey, not a destination."
Now, from general philosophy to gear philosophy: An extension (done by others, not me) to your one tooth hobbing is to make a rack-shaped cutter referred to as a "pseudo-hob". The cutting teeth are rack shaped, but there is no helix. Cutting time is reduced because more than one tooth is cutting per turn of the arbor. The cutting is spread out over several teeth on the gear blank and if the gashes in the cutter are timed so that they are spaced around the arbor, the different cuts are spaced out over the rotation of the arbor. The pseudo-hob can be made up of a stack of disc-shaped cutters and these can be made on an ordinary lathe if they have only a few cutting edges. I am posting a few graphics showing how to make simple form-relieved cutters without using a relieving attachment.
Archie
P.S.: These are not my graphics, but I believe originated from John Stevenson. (Now, that is a familiar name.)