On my site I have a series of pics showing the process of making new wheels
However, in the very early days, the wheel was divided with a slotting saw
and then the teeth were *filed*
in a jig using a file with the tooth
profile. Kind of like the setup used in filing a chain saw.
From there it went to "rounding up" cutters. These cutters (still useful
today) work like a circular file. I still fine it hard to believe that they
were made. The wheel is profiled to the tooth shape. Also, the thickness
of the wheel starts thin and gradually comes to full thickness. The sides
of the wheel (on the profile) are milled to provide a filing action as the
rounding up cutter spins in the slot on the wheel blank. To top it off, the
cutters have an attachment to catch the next tooth and automatically index
it into position.
This was the process used to make many Swiss music box gears and watch gears
in the early 19th century. When I have an oddball wheel for which I don't
have a cutter, I use this method.
In the late 19th and early 20th century, this tool was used to reduce the
wheel diameter and putting a proper shape on the teeth. Hence the name
"topping tool". Some people think it can be used to correct a decentered
wheel. However, this is not true. When used on a decentered wheel, the
teeth thicknesses are not uniform. Rounding up refers to rounding the tooth
Dewey Clark http://www.historictimekeepers.com
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