[R-390] Is this unusual?

[Tisha Hayes]

Spline screws have some distinct advantages over allen head screws. They
can take much greater torque without "camming out" like an allen head
screw. It has to do with the flat faces in the spline. You would need to
look at it with a really good magnifying glass or some diagrams on the
internet.

Those clamps require a significant amount of tightening to lock the gear or
dial knob to the shaft.

-- 
Ms. Tisha Hayes/ AA4HA

"In this denial of the right to participate in government, not merely the
degradation of woman and the perpetuation of a great injustice happens, but
the maiming and repudiation of one-half of the moral and intellectual power
of the government of the world." -- Fredrick Douglass, 1848