Drilled & Tapped Shaft Adapters

Today I worked on the shaft adapters that will attach to the motors. These are required because the shafts coming out of the motors are only 8mm in diameter, whereas the gears that will drive the chain have a 3/4" inner diameter. I'm using a 1.25" segment of steel rod, per the H&A drivetrain blueprints.

Mike has a handy tool that he let me borrow, that helps to center a hole in the steel rod I'm using for the shaft adapter. The tool has a pre-centered hole on one end, and it lets you place a blank rod in the other. The drill bit slides the through the hole and then drills a centered hole into the blank.




I only need two shaft adapters, one for each motor, but I actually built a total of four just in case. I drilled two with a 17/64" bit, and then went back and drilled two more. (Actually, now that I think about it, I do need a third one for the dome motor.)



Next, I tapped the shaft adapters with an M8 tap, to match the threads on the motors.



The adapters appear to fit the Saturn wiper motors well. I still need to grind some material out around the shaft adapter hole on the motor side, because the shaft adapter needs to fit snugly up against the motor body. Eventually a 1/8" diameter hole for a steel pin will be drilled and the pin inserted, perpendicular to the shaft at its base. This will help lock the shaft adapter to the shaft and prevent shearing, which is prone to happening when running the motors converted from 12 volts to 24 volts, which I plan to do.