Coarse pitch vs Fine pitch splines. Any difference in strength?

[billabke]

I am trying to design a couple of splines. The first internal spline has an ID measuring approx. 1.180 and a length of 1.360. And the second internal of about .800 and a length of .925. I have a little room to make the ID a bit larger or smaller as needed. So I wanted to know if there is an advantage to going with a fine pitch spline or more coarse pitch. I am pretty sure the first spline set is being made from 4140 or something around there the second set will have the internal being made out of aluminum.
From what I have been reading I have kind of come to the idea that the pitch size doesn't really change the strength. Not sure if that is true. Id rather go quite fine since I have several fine pitch shank cutters to use.
Thank you in advance for any incite.

 

[tbuelna]

billabke,

As long as the spline teeth are accurately produced, then they should load share and the difference in DP/tooth count is not a big issue.

Watch your spline L/D ratio. Once you get greater than about 1.0, edge loading due to torsional wind-up or lead errors can become an issue.

Hope that helps.
Terry

 

[billabke]

Thanks that is pretty much the answer I was hoping for.