[Bruce Newendorp]

We have used the plastic couplers several years and they work well. An easy way to connect the coupler to a keyed shaft is to buy a 4" V belt pulley and cut half of the pulley off leaving a 4" round flange with a nice keyed shaft coupler. Drill 4 matching holes in the pulley flange and the plastic coupling, add screws, drill out the plastic coupling to 1/2", put it all on a 1/2" keyed shaft and you have a connection that will not fail.
We will be doing this next week for this year's robot.