I see I haven't updated this thread for a few years; I've done a lot of cutting, and a pot of machine repairs and upgrades too. First, a new linkage for the big right/left swing movement. The old setup wasn't strong enough and now that I have a milling machine, I have more fun.
The next repair was a stripped trapezoidal (acme) nut; this extended the tube for distant side cutting. I made a new nut on my lathe, and ordered a factory made one for when it fails. The one I made is still in there.
Some of the teeth broke, and so did the rotation gears of the cutting head (that flips the cutter vertical / horizontal). This was mainly from operating error, when I got caught on something or it dug into the ground. I got new thicker teeth, but they're serrated; I milled half of them smooth, the other half are as they came. I had to mill the mating area of the long tooth mounting plates to compensate for the thicker teeth.
I ordered big gears from a shop in Lisbon, they're standard parts and surprisingly inexpensive. Module 3.
I wanted a clutch, but it's just too difficult. So I settled on a sheer pin. I did some experiments to find the breaking strain of 8mm aluminum; 750Kg. Now I've upgraded to a 10mm pin.
I found some better pictures.
Here's one of the new teeth; serrated ones above and smooth edges on the row below.
The big new rotation gear and slip plate on the lathe;
Here I've finished the shaft that holds the slip plate in, it has a machined shoulder so the nut can be made tight and the 2 parts will rotate freely unless the aluminum sheer pin is in.
Assembled; I just gave the pin a whack with the hammer and it expands slightly and won't fall out. I had to replace it already and that went really easy.
The other side;
Attached to the hedgecutter and mounted on the tractor;
