Exmark metro 21 Operator's Manual page 32

POTENTIAL HAZARD
♦ A worn or damaged blade can break.
WHAT CAN HAPPEN
♦ A piece of the blade could be thrown into
the operator's or bystander's area,
resulting in serious personal injury or
death.
HOW TO AVOID THE HAZARD
♦ Inspect the blade periodically for wear or
damage.
♦ Replace a worn or damaged blade.
If it is necessary to remove the blade for replacement or sharpening, complete the
following steps:
6. Remove the blade. Make sure to grasp the end of the blade using a rag or a thickly
padded glove.
For Blade Brake Clutch Units: Remove the blade nuts, anti-scalp cup, accelerator,
and the blade (Fig. 19)
For Units without a Blade Brake Clutch: Remove the blade bolt, accelerator, and
blade.
7. For Sharpening: File the top side of the blade to maintain its original cutting angle
(Fig. 21A) and inner cutting edge radius (Fig. 21B). The blade will remain balanced
if you remove the same amount of material from both cutting edges.
Cutting Angle
8. Check the balance of the blade by placing the center hole of the blade over a nail or
screwdriver shank clamped horizontally in a vise (Fig. 22). If either end of the blade
rotates downward, file that end (not the cutting edge). The blade is properly
balanced when neither end drops.
9. For Installation: Make sure to grasp the end of the blade using a rag or a thickly
padded glove.
For Blade Brake Clutch Units: Install a sharp, balanced Exmark blade, the
accelerator, the anti-scalp cup, and the blade nuts. The sail of the blade must point
toward the top of the lawn mower housing for proper installation. Torque the blade
nuts to 15-27 ft-lb (20-37 N m).
For Units without a Blade Brake Clutch: Install a sharp, balanced Exmark blade, the
accelerator, and blade bolt. The sail of the blade must point toward the top of the
DANGER
Cutting Edge Radius
Figure 21
G0221
Figure 22
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G0220