Robot Arm gear box

I'm currently building a robot arm, and I needed some kind of gear box, to translate the movement of one of the motor by 90 degrees, for the wrist pivot.

I looked for some kind of cheap gear box, but couldn't find anything affordable, so I decided to make my own.

it uses 1/4" shaft and R4-AZZ bearing.I also used 2 x 1/4" collar to prevent the shaft from moving. I made those on my lathe, but they can be bought in any RC hobby shop.

Bevel gears I used have the following specs:
- Bevel G