Friday, January 27, 2012

Keeping it Sharp

How sharp you make your tools is a matter of personal choice. I like my shovels to be sharp enough to cut through minor roots, but with my rocky soil, I won’t repair an edge to razor sharpness every five minutes. On the other hand, when I’m trimming back my lilacs, a razor-edged pair of pruning shears makes the job quick and easy.

Sharpening tools is a slightly more complicated procedure than removing rust. Some tools like shovels, axes, hoes, and trowels are best sharpened with a hand file, while other tools like pruning shears and knives call for a honing stone. Depending on how dull an edge is, some tools may require the use of a high-speed grinder.

A good guideline to use when sharpening is to follow the bevel already on the tool’s blade. Recommended sharpening angles range from 10 to 45 degrees depending on the tool and its use. In general, the angle of sharpness determines the length of the blade’s beveled edge, so use the angle of the blade as a guideline when sharpening.  For example, blades sharpened at low angles have relatively wide bevels. Knives and pruning  shears, tools that need finer edges for cutting, should be sharpened to between a 10- to 25-degree angle.  Tools used for heavy-duty chores that dull the blades quickly, like hoes, shovels, and mattocks, only need to be sharpened to a 30- to 35-degree angle. The bevel on these blades is relatively short. Understanding this relationship is the key to successful sharpening.

The tools needed for basic sharpening are neither expensive nor complicated. The most basic sharpening tool is an 8 or 10-inch-long mill file with a bastard cut which you can purchase at your favorite hardware store for about $8 to $12. When sharpening a tool with a mill file, work by drawing the cutting teeth in one direction over the edge being sharpened. For best results, hold the tool steady in a vise, or other bracing system, keeping the file at an angle from the plane of the cool’s working surface as you push it along the edge you are sharpening. And since sharpening edges with a mill file requires two hands, get one that has a handle on one end. This makes it easier to maneuver and get a good edge. Remove the hoe from the vise (if applicable) and test it in the soil. You should notice a measurable difference in the sharpness as it cultivates the soil.  Once you complete your sharpening work use a rag with some vegetable oil and wipe it on the tool to help prevent rust.

(by Jeff Yearington, Farm Outreach Worker, Lincoln University)

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