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Finding and Locating key in shaft using formula

Machinist101

Plastic
Joined
Dec 6, 2018
So I have an issue where there is a shaft that it timed depending on the location of the keys. The top shaft's key must be pointing up relative to the top of the machine. The key on the side shaft for the transfer cam must be pointing out away from the machine.

The issue I'm having is the bevel gears that were purchased for the rebuild have the keys broached in the same location on both gears (in the middle of the teeth). So the keys for the top shaft and the side shaft are off half the the center distance between teeth.

I use to have a formula in my tool box that used radians and degrees that I could use to position the shaft in the Bridgeport and find the proper location. Maybe I could get some help either finding a formula or a technique to get the keys to there respective timing.
 
360 degrees divided by number of teeth yields degrees per tooth. Divide this by two to get degrees per 1/2 tooth. This is the angle to rotate one keyway relative to the other.
 
That's about it. I do not see any reason to get radians involved.

Since your gears already have key ways, you are probably going to have to add a multiple of the number of degrees per tooth to the half tooth number so that the new key way does not overlap the original one. And do mark them so you do not confuse them during assembly.



360 degrees divided by number of teeth yields degrees per tooth. Divide this by two to get degrees per 1/2 tooth. This is the angle to rotate one keyway relative to the other.
 








 
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