SOLAR MOWER - mounting the blade

Blade Mount
	This was one of the more challenging parts of the job. The blade must be mounted very securely and I was very concerned about safety. I spent 20 minutes or so at the local Grainger's will call desk with a very helpful guy. He showed me a variety of split taper bushings until I found one that had holes that matched the 2 extra holes in my blade. Then I found the smallest V-groove pulley that I could to use to secure the bushing to the motor shaft (see below).
Note that the blade must be absolutely sharp for this mower to be effective. There is less power available -- about the equivalent of 3HP, and the lower RPM is also a factor. My Leeson motor is rated for 1800 RPM which is about half the speed of a gas engine. So I bought a brand new blade from Sears and then sharpened it on my grinding wheel. I was careful to keep the balance the same so it wouldn't vibrate the motor to pieces.
	The blade thickness meant that I had to go to the hardware store to find some longer grade 5 bolts to replace the original 1" X 1/4-20 ones from the mower. (Grade 5 is a hardened bolt identified by 3 raised radial lines in the surface of the head). Since the holes in the blade are bigger than 1/4", I was very careful to align the blade so that it was centered on the motor shaft to prevent vibration and excessive wear on the motor shaft and bearings.
Why a split taper bushing? These bushings are used as mounting hubs for pulleys on industrial equipment. Their advantage is that they hold the pulley very firmly to the shaft and they can accommodate a lot of vibration. As the mounting bolts are tightened the taper compresses onto the motor shaft, and also exerts pressure outward into the hub of the pulley. The bushings also have a D slot to prevent rotational slippage. The motor came with a keyway for a square key that is the same size as the keyway in the bushing. My bushing is a Browning "H" type for a 5/8" shaft. (learn more)

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