Swiss Dollar Watch

[david pierce]

Jan,
For a mill the size of the NANO lathe the 1mm cutter would be on the upper end of the cutter diameter that the machine can handle. When I worked in a machine shop most of the manual milling was done on BRIDGEPORT milling machines. The machines weighed 2000 pounds and did what they were supposed to do. Even with that much mass a 1/2 inch cutter was the largest size you could put into the mill and really push it. Going to a 5/8 or 3/4 inch end mill cutter required going a little easier on the feed. We also had a massive KEARNEY-TRECKER mill that almost went up to the ceiling of the shop. The motor was the diameter of a storm drain and large enough to crawl through. That machine could take a 1 1/2 inch diameter cutter with a 1 /12 inch deep cut into a solid steel block and cut it like a knife through butter. No shaking, no chatter only metal chips spraying out of the machine. This was all due to the relationship of the machine mass to the force against the cutter. I think if you put some really small cutters on your NANO you will see it performing nicely.
Jeweling chucks are themselves collets but are designed to fit into other collets. They are designed to hold material that has more width than length. They have positioning screws that run through the back of the collets to support the piece to be machined from the back which will prevent the workpiece from being pushed back into the collet while it is being cut. For a longer shaft the positioning screw can be removed or backed out and it should then function like a regular collet. Uncle Larry always has sets of these for sale and an entire set should not weigh much more than a large letter.
david

[gerene]

Thanks David, I found a description of the jewelling chucks in De Carle’s book “The Watchmaker’s and Model Engineer’s Lathe”. He calls them brass split chucks. I suppose they are the same. According to his explanation they are made in sets of 20 with a 5 mm diameter body and with a hole or bore ranging from 0.20 to 0.32 mm. I have put them on my wishlist

You must be right that milling in the nano lathe can only be done with very small cutters. I did however buy the Proxxon Micro Mill MF70 which is more convenient anyhow and allows cutters up to 3 mm. Not a whole lot but already more than the nano lathe and I don’t have to do the conversion.

Jan

[david pierce]

Jan,
Every machine has its limits, even the big ones. These limits are found through trial and error.
david

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