Richard L. Parish | 2/27/2006 10:27:51 PM
Pruning shears are an important tool for most homeowners and grounds maintenance professionals. They are useful for trimming trees and shrubs and for harvesting fruits, vegetables and flowers.
Dick Parish, an engineer with the LSU AgCenter, says pruning shears come in two basic styles and in a wide range of sizes and price ranges.
The two common types of pruning shears are bypass and anvil. Bypass shears have two curved blades that slide past each other like a pair of scissors. One blade is usually thick, with a mildly tapered edge, while the other blade is thinner and sharpened. Anvil shears have one flat blade (the anvil) and a second, straight-edged sharp blade that closes against the anvil.
"It is sometimes assumed that a bypass pruner can make a neater cut, with less crushing and tearing of the wood," Parish says. "But testing has shown that a bypass pruner will actually crush the branch more than a sharp anvil pruner."
He says most professional pruning shears are the bypass type while homeowner shears are available in both types.
The engineer says the force required to operate various shears can be significantly different. LSU AgCenter personnel conducted a test by cutting hardwood dowels to evaluate the cutting force required by several pruning shears.
"Neither the anvil nor bypass type has a clear advantage," Parish says. "But shears with Teflon-coated blades generally required less force."
Parish says some anvil shears have a linkage that causes the blade to slide relative to the anvil while closing. This sawing action contributes to a lower force requirement when compared with anvil pruners that just close without the sliding action.
Other pruning shears incorporate a ratchet action such that multiple strokes are needed to cut a large branch, but the required force is less.
The cost of a pruning shear can vary from $10 or less to more than $50, Parish says.
"The higher-priced shears are generally built stronger and may use better materials such as stainless steel," he says. "Some inexpensive shears have plastic handles and are prone to breakage."
Parish says the higher-priced shears are designed for professional use, but price alone isn’t a valid indicator of force required to cut.
"Some of the less-expensive shears do an excellent job of cutting with minimal effort," he says. "Some of the shears have Teflon-coated blades for corrosion resistance and reduced cutting effort. Testing has shown that the Teflon does indeed reduce the force required to make a cut."
Parish says cleaning pruning shears after each use will prolong the life of the tool. He suggests a solvent may be needed to remove sap from the blades.
"Avoid cutting anything except branches if you want to keep your blades in good condition," he says. "A pruning shear is not a wire cutter."
Oiling the blade after cleaning will help prevent rust. The cutting blade should be sharpened as needed.
"An anvil pruning shear with a sliding blade is probably the best all-around shear for a homeowner," Parish says. "It is inexpensive and has a low cutting effort. A small bypass shear is better for flowers and very light pruning."
Parish says most professionals use higher-priced bypass pruners.
"The professional bypass shears may last longer but don’t necessarily cut easier or cleaner," he says. "Ratchet-type anvil pruners are a good choice for cutting large branches more than one-half inch in diameter."