Look sharp, be sharp when you cut the grass

At the height of summer, a good haircut makes a good impression. People notice, and the new growth that comes in is more even and attractive.

Plus, a proper haircut reduces the chance of fungus, disease and browning.

We’re talking about cutting the grass, of course. Summer is the most important time of the year to keep a mower blade sharp.

Sharpening a blade can save a trip to the hardware store. And there is something about mower blades that causes homeowners to dig in their heels. Enough is enough. It just cost $8,000 in depreciation to drive that shiny new SUV off the lot. The difference has to be made up somewhere.

A mower blade is a good place to start.

Sharpening a blade is not difficult once you get the hang of it. The whole process takes about 10 minutes. It’s so easy that some lawn worshippers actually sharpen the blade before each and every cutting. A sharp blade results in a sharp, healthy lawn.

Here’s how it’s done:

First, pull off the spark plug wire before messing around under the mower. The cost of sewing fingers back on will require several lifetimes of blade sharpening to recoup.

Tip the mower with its fuel tank and carburetor up so gas doesn’t leak out all over the driveway. Don’t tip a mower on the lawn. Big splotches of dead grass due to leaking gas and oil defeat the purpose. Block the blade with a chunk of two-by-four and remove the bolt with a socket and ratchet wrench. Most mowers have a center bolt and sometimes two outer bolts. Mowers with a blade clutch have two outer bolts. On these, don’t remove the center bolt, it holds the clutch in place; getting it back on can ruin your whole day. Mark everything so it goes back on the same way it came off.

Once the blade is in hand, check it carefully. It shouldn’t be more than about an eighth of an inch out of whack on either side. Rotary mower blades create their own air flow under the mower, sucking the grass upright for cutting, chewing and spitting out the side or back like a ballplayer with a big wad of chaw. Both sides of the blade must be even for the air to move right. Also, an unbalanced blade can shatter the engine crankshaft, and that means a new mower.

There are gizmos that purportedly sharpen the blade while it’s still on the mower. They tend not to work very well, but if used, empty the gas tank first. Grinding causes sparks. Sparks cause fire. Fire causes explosions. The picture may be clear by now that removing the blade is preferable.

Do-it-yourself magazines often advocate locking the blade to a workbench with C-clamps and using 50 strokes of a medium mill bastard file at least 10 inches long to sharpen the blade. But anyone in their right mind uses a bench grinder, since lower-end electric grinders cost about the same as a high-quality mill bastard file.

Follow the existing bevel on the blade, grinding or filing at about a 45-degree angle. Do not grind anything off the bottom side of the blade, or all is for naught. The cutting edge has to be at the lowest point, and beveling the underside of the blade increases the drag and beats the grass to death. It is considered proper form to grind off big nicks on the underside of the blade, but keep it flat. As for deep nicks, grind right over them. Think of nicks as merely increasing the overall cutting edge. They don’t hurt anything as long as the blade still balances out.

Balancing the blade is extremely important. Pound a nail in the wall and hang the blade on it. It should be level. If not, keep grinding. But don’t overly distort the shape of the blade or it won’t work right. Keep the blade edge a bit on the dull side – butter-knife sharp rather than carving-knife sharp. It will just get whacked to the desired dullness in 30 seconds anyway.

Don’t overgrind. The metal is soft, and heat can warp it or make it mushy. A good test is to be able to touch it with a finger.

To replace the blade, tighten the bolts lightly, then torque down hard.

There are specifications for such things, but looking them up requires more time than mowing the lawn. Just remember that the experts say undertightening is one of the most common causes of a bad hair day for your lawn.

If a blade is severely damaged or bent and needs to be replaced, resist the urge to try a “better” type of blade. Most mowers are designed with one blade in mind, and unless you really understand the circular logic of rotary mowers, stick with the original.

Jim Kjeldsen is a former assistant news editor at The Herald who now owns and operates La Conner Hardware Store in La Conner.