Looking for a worm gear set to shift the rotation of a crank handle 90 degrees. The existing crank handle attaches to a 9/19" [15mm] spindle; so the worm gear needs an inside diameter of 15mm.
Have a look at this youtube video; timecode 3:31, to see what I’m trying to do.
Wish RobotShop could carry more gears, but unfortunately at this time we don’t have that. In addition to igor_X’s suggestion, you can also try QTCgears and McMaster.