Next morning I decided to have a closer look at the damage and try to finish the thicknessing by hand. On the Jet JPT-260 it is possible to disengage the feed rollers which should allow for manual operation. After setting everything up I disengaged the rollers and tried to feed a piece of wood in. Imagine my surprise when it wouldn’t go in.
I stopped the machine again and decided to have a closer look at what was wrong. I guessed the wood was sticking against the in-feed roller so I tried turning the feed roller drive train by hand – it wouldn’t budge a millimetre. I assumed that the broken teeth on the plastic sprocket must some how be jamming against the pulley sprocket even though that seemed unlikely. The solution therefore was to remove the pulley and see if the whole system would rotate.
You can clearly see the damage in once the pulley has been removed. I again tried to turn the feed rollers by hand but they still wouldn’t budge. That, I felt, pointed to a different problem. I also noticed that when I tried to turn the plastic sprocket one side of the drive chain became tight and the other loose indicating that was the problem was somewhere else. The tensioning wheel the chain goes around also showed signs of being put under stress. Frustrated, I decided to remove the plastic sprocket to free up the chain, I figures I had to remove it anyway as it was clearly in in need of replacement.
And a close up of the damage, you can clearly see that the teeth have been completely worn away.
This left me with a very empty looking machine.
I lifted the chain off the sprockets and tried turning the feed rollers by hand.
The out-feed roller rotated quite easily by hand the in-feed roller on the other hand is seized up tight. I now believe that the failure of the machine probably isn’t related to me accidentally feeding it a bit of wood that was too thick. While I could imagine jamming a piece of wood in the machine could cause the damage to the plastic sprocket I can’t believe that it could cause the bearings to seize. In fact since the machine ran for a good half hour after the jamming incident I can only assume that they probably aren’t actually linked.
Looking at the parts diagram I think I’m going to have to completely disassemble the cutter head assembly to get at the bearings for the in-feed roller. That’s irritating because it’s a lot more work at a time when I already have more than enough to be getting on with.