One day I intend to make a watch.
I’m still a long way off, but tonight I made a good step in the right direction :)
A large part of a timepiece is of course the wheels and pinions. I’ve been contemplating how to cut them without bankrupting myself buying the cutters.
The Sunderland gear planer uses a fairly simple cutter for racks, and generates the curves of the spur gears by coordinating the cutting and a rotation, so the gear blank rolls against the rack as though it already had th teeth.
I have several old engineering texts with some of the relevant details in:
https://i.postimg.cc/TYFhHPcZ/D3-D84...19443-FAE8.jpg
Of course I don’t have a gear planer, and generally they are for much larger gears, but I can use the technique with a little bit of lateral thinking.
First make a rack form cutter, simple lathe work.
https://i.postimg.cc/gkT6FsGt/0-DC70...-E77-DFEFC.jpg
Then wack it into an indexer on the mill
https://i.postimg.cc/bvQGnjk4/CD60-E...735-ACA4-C.jpg
And create some flutes for the cutting edges.
https://i.postimg.cc/mDLrF1bF/3009-D...EC4-FA16-F.jpg
Then handily I have recently bought a kiln (for enamel) which I can use to Heat treat. So much easier than a blowtorch.
https://i.postimg.cc/MpffWBT6/608-F8...C2881-BCC6.jpg
I decided to keep the tooth count smallish for my first gear - 30 teeth /12degrees each. That also means I can use the simple divider. To assist my little brain I wrote down all the teeth angles so I could tick them off as I go.
https://i.postimg.cc/x1mqrSxq/232-BA...-DE84970-B.jpg
Then it’s a question of put on the right cut and index /cut / repeat...
https://i.postimg.cc/KjY4Ckwy/D3-F63...B7-CB063-D.jpg
Once the first pass is done I rotated the indexer by 6 degrees, moved the cutter by an equivalent linear amount and cut it again. This generates the tooth curves.
The end result is gear shaped:
https://i.postimg.cc/sDvvcW5Y/169-DB...71-C81-D11.jpg
And meshes with another 48dp gear nicely.
https://i.postimg.cc/9ftMMYjh/036036...5162387463.jpg
I got a beautiful pattern when parting the gear blank off the stub it was machined as part of.
https://i.postimg.cc/g0PjmBQs/A4-ED5...78-E98-C94.jpg
There is more work to do, but I think the method will work without too much effort.
Dave