I have a automatic gear cutter made by Flather, which I gave a thorough overhaul complete with re scraping of the carriage sliding surface; this machine is not a hobber, it uses single tooth space cutters, it will cut up to about approximately 36" diameter and 10" of face width; it cuts a tooth space, quick returns to the starting point, indexes and feeds into the next tooth space automatically and keeps on doing that sequence until it cuts all the spaces. It does not have a device to stop the sequence when all the teeth are cut, so you need to keep an eye on it. The indexing for differing numbers of teeth is done by change gears driving a worm and worm gear on the work spindle, and there are change gears for speeds and feeds as well; when I got the machine, there were no change gears with it, so I had to figure out the pitch of them to suit the center distances of the shafts, and was lucky to find a change gear chart of a similar machine made by Brown & Sharpe; all in all, I probably had to cut more gears to make the machine usable that I have cut for pay with it.
One thing I will say is that the machine showed some lapses in workmanship when it was built; it was not a really high class machine, but it will cut a gear and quickly at that.
John York