I'm looking at a hobby micro servo, which has a 5mm splined shaft output. Specifically, this is a Tower Pro model SG90 or clone. Close-up photos of the shaft below.
I've found online diagrams for both a 30 degree Flat Root Spline shaft, and a 30 degree Filet Root Spline. Can someone please explain the difference between these spline designs?
I'm adding a drawing approximating the photos (and a hub) of a 21 tooth spline with a 5mm pitch circle and 45 degree pressure angle. (To simplify, I've not used involute teeth.)
I have filleted the exposed corners of the teeth at 0.06 mm. Is it these that make it a fillet root spline?
I've also added a fillet to the empty spaces joining the faces.
P.S. here's a link to my in-progress CAD model. Feedback welome.