Mechanical Unit Circle and Trigonometric Functions

I adjusted some parts to have tighter tolerance, and these adjustment take out backlash pretty much completely.
I enlarged the big gear by 0.3mm and modified the inner hole for a tighter fit. Also increased the size of the arrow piece for tighter fit.

Furthermore, the pins are increased diameter to make them snug fit with the rings, and the connectors on the feet are thickened for snap fit to the lower housing.

The degrees plate had lots of loose parts (the inner form of degree signs, zeros and four) so I fixed that as well.
The last part I adjusted is the tan slider, as I noticed it got stuck at the middle and right pin. I made the upper and lower radius a bit bigger and added two guided bulbs at the top slider and made the connection to the cos/sin slider a tigher fit. I could also have done this with the tooth rack, but it seems not necessary.