My solution uses a cordless screwdriver, a microcontroller, and an H-bridge driver, How many threads get rolled is easily configured by modifying the timing on the software running on the microcontroller and the speed setting on the screwdriver.
I have read about other (very expensive) machines that thread spokes very quickly at the pull of a lever. My solution, threads spokes at the touch of a button.
Step 1: How it works
The idea is to automatically turn the crank handle on the threading machine clockwise
for a period of time and then turn it counterclockwise by controlling the screwdriver.
As the handle is turned clockwise, the die "grabs" the spoke and advances.
Rather than have the screwdriver advance along with the handle, a 90 degree crank bit
is built for the screwdriver. This crank bit gets a washer at the tip which accepts the
handle. The handle freely slides in and out through the washer.
Finally, a spring is loaded on the handle. Now when the spoke is inserted and
pushed against the die, the spring causes the die to slightly force itself onto the spoke,
allowing the die to "grab" and advance.