On 01/02/2016 10:02 PM, Cecil Thomas wrote: ... snip > Several years ago I wrote a program to "generate" involute gear teeth > by making multiple cuts of the same tooth from differing angles with > a rack shaped cutter. This eliminates the need for the different > cutters when making only one cut per tooth. I have used it many > times to cut relatively large gears with a relatively small number of > teeth with virtually no noticeable error. > > A few days ago a friend who repairs watches wanted to know if I could > figure out what gear (wheel to you watch guys) size, pitch or module > and number of teeth would be required to replace a missing one. (the > original was long gone). I had no problem working from the center > distance and the matching pinion coming up with the appropriate design.
... snip I have been looking at clock gearing off and on for a while. So far, I have found that clock tooth forms are cycloidal, but not really. It seems there is a British standard which is based on the ideal cycloidal form but uses a circular arc for the curved part of a tooth, rather than a cycloid, and clearance is added according to practical experience. I haven't been able to find the contents of the standard, but I'm still looking. My plan was to use a very small diameter (.015") end mill as a universal gear cutting tool for thin wheels from sheet brass. The wheel can be drawn in CAD, converted to g-code then cut in XY without using a rotary axis. I would appreciate any links or information that could get me closer to actually cutting wheels and pinions. Although, pinions are a different kettle of fish. I'm also working on a New Haven clock that seems to use custom screw threads (#3-40?) that don't appear in Machinery's Handbook or anywhere else. -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/ ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
