Gallery, Projects and General > How do I??
Any Mathmatitions On Line (lathe change wheels)
John Stevenson:
John,
What size is the 63 teeth gear on the OD and bore details.
I have a box of old change wheels here from auctions and college clearouts, might just have one.
bertie_bassett:
as said by others, for a short thread I doubt it will make much difference.
lead screw pitch and other gear tooth numbers would be needed to calculate the resulting screw thread and thus the actual error.
alternatively, there are a few online gear train calculators about, might be easier to use one of them to work out what thread can be cut with a 64 tooth gear. must be one around for a Harrison
tom osselton:
Does any of your buddies have a cnc mill?
awemawson:
Is not the thread pitch error going to be constant when expressed as a percentage of nominal? So 0.5 tooth out of 63 is:
(0.5 / 63) x 100 = 0.79% as an error in pitch so a nominal 1.0 mm pitch would be 1.0079mm etc :scratch:
So if you work out how long the thread that you are cutting is, you can easily see if the error is to much to tolerate.
John Hill:
John, I think you can make a 63 hole indexing plate!
Just cut a plate to size and clamp your borrowed 63 tooth gear centred over the plate then drill an index hole as close as you can in line with each tooth of the gear. You now have a 63 hole divider plate. It will not be terribly accurate but if your dividing head is 40:1 your errors will be divided by that. If you are still not happy with the accuracy use your first plate to index and drill a second plate which will have errors 1/1600 compared to your first manual drilling.
John
(I hope I am right! :Doh:)
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