"I built it to clear brush alongside the road. It does a great job," says Bill Hoff, Nakina, Ont., about the 3-pt. mounted, pto-driven rotary brush cutter that he built.
The brush cutter makes use of an automotive differential which belt-drives a 12-in. carbide-tipped saw blade, and is mounted on Hoff's Massey Ferguson GC2310 TLB Estate Tractor.
"The tractor pto drives the axle side of the differential to increase its output speed. The differential's output speed is further increased through a belt and pulley system, which gives the saw blade a speed of 3,000 rpm's at the tractor's 550 rpm pto speed," says Hoff.
The brush cutter mounts on a frame made from 2-in. sq. tubing, and is raised and lowered by using the tractor's 3-pt. hitch system.
Hoff machined a mandrel to hold the saw blade and attached it to a vertical shaft. The shaft is secured by 2 pillow block bearings to a 5 by 9-in. flat steel plate that's welded onto a length of 2-in. sq. tubing. The sq. tubing slides into a receiver hitch that Hoff welded onto the frame.
A 1/2-in. threaded rod positioned between the receiver hitch and sq. tubing is used to adjust belt tension.
He used a pair of U-joints and 1-in. sq. tubing to make a 14-in. long pto shaft that hooks up to the tractor's original pto. The belt and pulleys are protected by an expanded metal guard.