Re: [CAD_CAM_EDM_DRO] 21 T spline
we have a 1970's WABCO (Westinghouse Air Brake Co) earthmover and the spline collar on the output shaft of the front motor is hammered. We have found a waterjet guy who says he's cut splines for other construction and mining equipment, but he nor I have a spline wizard on our CADD programs.
The collar is pretty trashed, and the male spline is in a very hard to get to place, so it is hard to get good measurements. So we are thinking of making a ring to some ANSI standard spline (B92.1-1970?) and seeing if we can get it to fit. I have a 3D printer and if that works, then we'd cut a thin section on the waterjet to confirm. However, i don't see a 21 tooth spline in the 17 "common" pitches in my 19th edition Machinery's Handbook.
MH 23 has a measurement table under Checking Gear Sizes. This chart is for measuring over proper sized wires to get pitch diameter.
To get Diametral Pitch on splines you take the number of teeth and add 1 then divide by the nominal OD to get the DP.
21 add 1 equals 22. 22 divided by 2.75 equals 8. 30 degree PA splines use a dual number system so this is called an 8/16 DP.
Might someone have a plugin or knowledge or gearotic etc to help make a dxf of said spline, so I can give it a try? Sorry for the spartan dimensions...
1970's made in USA machine
spline teeth - 21
pressure angle 30 (guess)
major dia is ~2.75 (across an odd number of teeth)
minor dia of male shaft ~2.56
The 2.56 minor on the shaft does not seem right. The minor on the female in this case should be 2.500.
If you take the reciprocal of first number of the DP times 2 is the difference between OD and ID.
Recip of 8 is .125 times 2 equals .25 so 2.75 OD minus .25 gives you a minor of 2.500
It so happens I am cutting some internal 2.75-21 splines at this moment. It will be interesting to see how a waterjet will work.
Ed.