GARDENING : Stay a Cut Above With Sharp Tools

High-quality garden tools can last a lifetime with proper care. The steel heads on hoes, shovels, rakes, spades, trowels and picks should be kept clean, sharp and rust-free; rotary mower blades should be sharpened and balanced every few months.

Here are tips to help you prepare your tools for the gardening season:

CLEANING

* Clean tools after each use and store them in a dry place. Scrape off mud and dirt with a putty knife or similar tool, and wash off the remaining dirt with a hose.

* Remove rust with a wire brush, sandpaper, or a rust-removing chemical, then apply oil with a brush or rag. To clean and oil a hand tool in one easy operation, fill a 5-gallon bucket with sand and add used oil drained from the crankcase of your mower or car. Thrust the tool into the oil-soaked sand several times. The blade will emerge oily and clear of rust. Repeat the process occasionally during gardening season to prevent rust.

SHARPENING

Keep cutting and digging edges sharp to make gardening easier and to prevent possible breakage caused by excess pressure on tool handles.

* You can sharpen shears, sickles, pruning knives and other cutting tools by grinding, filing, or by using special sharpening stones such as a whetstone or slipstone.

* If a cutting edge is dull or nicked, it should be power-ground or filed to remove the nicks and restore the bevel. Knives, scissors or axes should be finished to a sharp edge with a whetstone or slipstone.

* To sharpen digging tools, place the tool in a vise and use a coarse lO-inch file to restore the original edge--usually a 45-degree bevel. On files, the bevel should be on the outside edge of the blade. A 60-degree bevel is best for general use; a 30-degree bevel for cutting heavy weed growth. On hoes and shovels, sharpen the corners as well as the cutting edges.

* It’s important to keep axes sharp. Clamp the head of the ax, edge up, in a vise. Use a medium-cut mill file, never a power grinder, which can ruin the blade’s temper. Hold the file flat against the head and draw it upward toward the cutting edge, lifting off at the end of each stroke.

File both surfaces, rounding to a convex profile. Retain this profile to the corners of the blade; don’t taper the corners. Check the edge by looking down its length. Bright spots indicate dull areas. Keep filing until the edge looks almost invisible. Finish by honing the edge with a round slipstone. Slide the stone along one side and then the other in a circular motion.

SHARPENING ROTARY MOWER BLADES

Rotary mower blades should be sharpened and balanced twice a season, or at least frequently enough to retain the original cutting-edge angle. (A dull blade will tear the grass instead of cutting it and will also strain the engine; a badly nicked blade can cause vibrations; an improperly sharpened blade may not provide enough lift to pick up the grass and cut the lawn evenly.)

GARDEN TOOLS

To sharpen, follow these steps:

* Always disconnect the spark plug or unplug the power cord first. Grasp the blade in a gloved hand or with a heavy rag and loosen the securing nuts or bolts. If a bolt sticks, apply penetrating oil to the bolt and tap the wrench with a hammer.

* Remove the blade and check the stiffener for cracks or bends. If you need to replace the stiffener, use a manufacturer’s recommended part--a bent or homemade part can cause vibration that will damage the engine.

* Clamp the blade in a vise and sharpen with a medium-cut flat file along the original angle of the cutting edge. File in one direction only--toward the edge. You can also use an electric drill sharpening attachment, available in hardware stores.

* Use a screwdriver or knife as a pivot through the center hole of the blade to balance it. Check the balance one way, then flip the blade over and check again. If the same end of the blade drops consistently, file some metal from the rear of the heavy end (not from the cutting edge). This will lighten the blade without harming the edge.

* If the blade is balanced both ways, reinstall it, making sure the lifts point upward toward the deck when the mower is right side up.

Note: A bent blade will make a ragged cut, may scalp the lawn in spots and the vibrations may cause serious engine damage, so it’s best to replace it.