This project got started when my wife decided to redo her garden in the back yard. I had to trim all the brush and small trees out of the way growing along the back fence so the sunlight could get there. The backyard ended up with a pile of brush about 10′ square and 6′ high. I kept all the branches that where at least 1/2″ in diameter or bigger in another pile I want to cut up for a gassifier project.
I though my father still had a chipper and planned to borrow his for a day or two and clean the stuff up but I found out that he had sold it last year when he planned to move. OK… I really don’t have a way to go rent one or the money so I decided it was time to get back to work and build one.
I did a bit of research on the net and found that most of the small ones seem to use one of two types of blades systems. Either a modified weed-eater type thing with multiple swinging small blades or some kind of large disk with slots in it and blades mounted above the slots. I decided to try the weed-eater version as I had parts I could use for that in my junkbox.
A 6.5hp Harbor Freight gas engine that was bought to operate an large aircompressor was to be used as the motive force. I built a bottom frame from recycled bed frame angle iron and mounted the engine. After mounting the cutter to the frame I found that it was binding in the sleeve bearings I used and I couldn’t get it shimmed out properly to stop it.
Hmmmm…. Back to the drawing board. After looking around in my junk some more I found the cutter end of a yard edger I stripped a couple of years ago. I mounted this one the frame and then built a cover with chute feeding and discharge ports and mounted it on the extension arm and on the frame. There is another bracket that is mounted on the front that is not shown in the pictures. I had to make a new blade for it as the edger blade was a triangular shape and would not work for this putpose.
The first time I tested it, it worked OK but I had made the inlet chute a bit too big. The nut holding the blade also came off and was lost in the yard somewhere. (it spins the wrong way of course) so I had to pause on it for a day or two.
Finally I found another nut that would fit at the local auto parts store and put the blade back on. This time after tightening it as much as I could, I drilled a hole through the bolt and the axle shaft and pinned the bolt to it. The blade was also recut to a sharper angle on the edges before it was put back on.
I added a small piece of sheet metal inside the inlet chute that closed off the outer edges where the sticks had been missing the blade and then reinstalled in on the frame.
It worked very well after that and I managed to get half the brush pile chipped up before it got suppertime. The engine has no problems powering it and hardly even slows down and I only run it about 1/3 speed on the throttle.
Click any picture for a larger view
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