Walter Murray replaced the blades on his 30-year-old Deere 214 47-in. riding mower with cutting discs fitted with three swivel-mounted blades.

He came up with the new design to save money on the cost of new replacement blades.

"With conventional single blades, when the blade wears out you have to replace the whole thing," says Murray. "With my design, I keep the disc and replace only the knives, which should last many times as long as conventional blades. I'll probably wear out the mower's engine or the wheels will fall off before I ever have to replace the blades."

In addition, Murray says his cutting discs mow faster and cut cleaner using less power. "They chop up grass real fine, even when it's wet," he says.

He used a sabre saw to cut three triangle shaped pieces out of 1/4-in. thick boiler plate. He drilled a hole in the center of each triangle and also at the end of each point to bolt the blades on.

"More cutting edges results in a better job of cutting. And the blades are so thin they hardly ever have to be sharpened," says Murray. "I came up with the idea last spring after I already had the deck off for minor repairs. The mower is about 30 years old and the blades and bushings were worn out. Rather than spend the money for new ones, I decided to try something different.

"I bought the 1/8-in. thick, 4-in. long disc mower blades at Tractor Supply Company. I bought the smallest and cheapest disc blades I could find because I didn't know if this idea would work. Both the blades and bolts came six to a box, so I had to buy two boxes of each. The bolts were actually more expensive than the blades. Now I have three blades and three bolts left over for replacement purposes."

The blades on disc mowers operate at very high rpm's, so Murray says his blades would probably work even better if his mower had enough power to rotate the blades faster.