Posted by Hobman on December 17, 2005 at 11:16:53:
In Reply to: Re: Gear Hobbing on a lathe posted by Ron on December 13, 2005 at 22:49:08:
Mostly, but not entirely true, Ron. What you just described is fully accurate and known as freewheel hobbing. Not the easiest trick to pull, but works sometimes.
BUT what if you were using a vertical slide attachment to begin with? Then you'd have the transverse feed. AND what if you had a uni shaft from the lathe gearbox up to the vertical slide attachment, to synchronize revolutions? Then you'd be almost there.
That idea has been proposed in different versions several times, but I don't know if it has been produced commercially.
Another idea is a complete unit attachment with direct copycat indexing.
Like this: (pic stolen from another internet board, drawing courtesy Gorge Barnes, idea from book Complete Metalworking Manual by R.H. Cooley in 1967)