Rim and Sprocket Drive Terminology

[Chainsaw Pete]

Rim and sprocket drive systems have some terms that have me confused. Please correct me if I am wrong:
The pitch is the first number in, say a 3/8 x 7 tooth small spline rim sprocket.

The 7 tooth refers to the number of 'pockets' or drive links that engage the chain. In other words, there are 7 slots around the perimeter of the sprocket for the chain drive links. Since the chain wraps around only half of the sprocket, only half of these teeth will engage the chain at any moment.

Small spline, standard spline, mini 7 spline, small spline - I'm lost here, but my best guess is these words describe the bumps on the drum that engage the notches in the rim sprocket.

 

[NSEric]

Different saws have different sized splines for the sprocket.
Small spline is 19mm, common on 50cc saws like a 550xp.
Large/standard spline is 22mm, common on saws like a 372xp or 066 stihl.
Mini spline is less than 19mm, im not sure on it's exact size it's only on small stihls and I dont have any of them.

 

[Chainsaw Pete]

Different saws have different sized splines for the sprocket.
Small spline is 19mm, common on 50cc saws like a 550xp.
Large/standard spline is 22mm, common on saws like a 372xp or 066 stihl.
Mini spline is less than 19mm, im not sure on it's exact size it's only on small stihls and I dont have any of them.

Are the splines the bumps on the driving drum that engage the pockets on the inside circle of the rim sprocket?

 

[NSEric]

Are the splines the bumps on the driving drum that engage the pockets on the inside circle of the rim sprocket?

Yes.

 

[Mad Professor]

Stihl small spline is different than other manufacturers like Oregon. They won't interchange on the drum.

 

[RedneckChainsawRepair]

To me it is stihl is mini and then standard aka large.

Oregon has a small and standard aka large.