[NoSkaOnTheRadio]

in retrospect, our driveshaft was kind of wimpy - we're working on a tougher replacement. thanks for the advice, too; we spun the keyangs for 60 rotations each and timed them, and found that there was a slight bias (very slight). it actually shouldn't have been a problem, but we had been running them with only our driveshaft and not our arm mounted. the prolonged single-directional rotation was probably the issue - as they rotated, they put more and more torsion on the shaft (even though we should have realized it anyway, we had no way to tell, since the motors were bolted down). better to find out now than in boston!

thanks again for all the help.