I replaced the failed Pittman dome motor last night, and thought I’d post some pictures of the failed gearbox.
The pen tip is pointing to the failed gear in the center of the picture. The teeth are almost stripped flat.
And this is the new motor opened up and how the gearbox should look. Again the gear in question is in the center of the shot. Notice the teeth!
I’m not confident that it will not fail again, and I may need to look at an alternative. I’m hoping the issue was my failed attempt to use batting tape to line the dome bearing to help with traction, but the gear may have been slowly failing with the constant harsh stop/starts on such a small gear. I know of at least one other builder that had a Pittman dome motor fail in the exact same spot.
I stripped my first set of gears in a motor this weekend. I was goofing around on the driveway showing Artoo to some neighbors across the street when suddenly the dome stopped working. I heard this really bad crunching noise then a very quiet motor spinning.
I quickly pulled him into the workshop and the dome off to see what was up.
A couple of months ago I had lined the inside track of my dome bearing with some batting tape to help the dome wheel grip. It had been slipping and the resulting noise was very annoying. The tape seemed to be the perfect solution …… until the gearbox failed.
I think what had happened was I’d left R2 sitting in the van all day and when I finally unloaded him the glue on the tape had heated up and when I started to spin the dome it balled up – jamming the wheel and breaking the gearbox.
Gerard had a similar failure trying to fix the squeaky slipping wheel. He’d over tightened the tension spring which stopped the dome the moment the motor stopped – but again this put extra pressure on the gears in the Pittman motor causing them to fail.
So for now I’m back to having a squeaky dome.