[Andy Brockway]

I agree with Joe on this one. The losses from the thrust angle and sliding friction use some of the precious power (battery) resources of our robots. Helical gears have their place in industry where excess power is available to drive them and strength in a smaller package and a quieter gear train is indicated.

I recommend miter gears if you really want to have a right angle, or any angle (I built a 45 degree gearbox for a machine at work), gearbox. Thrust loads still need to be accounted for but are significantly less.