Notes from Windward: #68
Fixing the Chipper
getting a key piece of equipment back on-line
We use a Jinma chipper mounted on the back of our mid-sized tractor, and for the most part we've been satisfied with it. The chipping part it does well enough, but the feed mechanism leaves a lot to be desired. Early last fall, a key part of the drive for the feed wheel came lose and got sucked into the chipper where it got quickly reduced into bits and pieces, doing a good deal of damage to the cutting blades as well.
Since it was late in the season, we just put the chipper away for the winter, but now that we're getting ready for another spring's worth of woodland clean up, it was time to get it back in operation. The first step was to replace the damaged linkage with parts we ordered from Circle G Tractors. They were most helpful and shipped promtly, even taking the time to assemble the three parts we ordered to make the repair a bit easier.
With the new feeder parts in place and working, the next task was to remove the inspection plate and check out the damage done to the blades themselves. In short, it wasn't pretty.
The next step was to pretty much disassemble the back of the chipper to expose the massive flywheel. It might actually be possible to access the blades without doing so much of a dismantle, but with air-driven tools and two pairs of hands, the work went quickly enough.
Annie proved to be a natural with an air wrench, and sorted through our various tool locations to find a deep 17mm socket that made short work of the task of removing the buggered blades. They're ground with cutting edges of both sides, so it was just a matter of flipping them over and bolting them back into place.
One of the bolts that holds the blades in place was missing, so we had to delay reassembly of the chipper until a relacement arrived. With that in hand, it was time to reassemble the chipper.
Part of our approach to repairing equipment is to use an "opportunity" like this to access the design and to make improvements. This is a China made chipper, and while it's well built in the sense that the flywheel is heavy and brings a lot of momentum to the task of chipping branches, the feed mechanism leaves a lot to be desired. A bit of internet research came up with the suggestion that the end of the feed driveline nearest the feed roller be taped to take a set screw, thereby lessening the chance of this particular failure recurring.
Picked up a 6mm tap and a coupld of set screws, so it was just a matter of working slowly and carefully to cut the threads into the hole already drilled into the square socket on the end of the driveline. Since the whole was just the right size for the tap, I can't help but wonder if this was a design feature that just got left out.
With the set screw in place, the driveline shaft was reassembled and the set screw secured. Don't know if this will give us total protecion againt the catastrophic error that allowed have of the feeder drive-line to eject its other half into the chipper, but it's clearly a step in that direction.
Notes From Windward - Index - Vol. 68