SCISSOR PERFORMANCE

Groomers are accustomed to thinking of the performance of their shears in terms of how well the edge is sharpened. Although a good edge is certainly necessary, it is just one factor in the cutting performance of a scissor. Blade tension and the honing of the ride area are also vital factors.

SCISSOR PERFORMANCE = EDGE + HONING + TENSION & BEND

ATTENDING TO THE RIDE AREA
The “ride area” of scissors is the area below the screw where the two blades pass over each other. If you open the blades and look closely, you will usually see a crescent shaped place where the blades are riding. Sometimes this area is referred to as the “crescent.” The smoothness of the finish in this area is directly related to how smoothly the scissors open and close. This is usually achieved in the final honing process of scissor manufacturing, before the scissors are assembled. Good maintenance of shears includes keeping this area cleaned and oiled. Lack of care can lead to scratching, pitting or corrosion in the ride area, which will affect scissor performance. Failure to give attention to this area, or use of heavy oil intended for other purposes, such as motor oil, can allow accumulation of hair and debris in this area and create poor scissor action. This can make the scissors or shears feel tight when they are not.
Before loosening the tension of your blades, clean and oil this area.

One of the differences between an untrained sharpener and a trained craftsman is that the untrained sharpener will often simply grind the blade edges and not pay attention to the ride area. The master sharpener will pay particular attention to honing of the ride area as well as to the blades. This is one difference between simply sharpening and reconditioning of shears. A reconditioned shear can perform better than new because of this kind of detailed attention.

WHAT MAKES SCISSORS CUT?
Although the blades of scissors look like two flat pieces that are joined by a screw, cutting is actually achieved by slightly bending the two blades inward toward each other. This is called the “bend” and is achieved during manufacture. It is a very precise adjustment. When we drop our shears or allow them to bang against walls or knock together in a tool drawer, we can cause the scissor bend to be knocked out of alignment. Another way scissors can be maladjusted is by a scissoring technique that pulls with the fingers and pushes with the thumb. Groomers who are used to forcing poorly performing shears through hair, or have never been taught to use a light thumb action, may develop this pushing technique that eventually forces the blades out of alignment. Although a sharpener can carefully adjust a scissor bend, an inexperienced person who does not know about different metals can break the blades of expensive shears when attempting to bend them.

SUFFICIENT TENSION IS NECESSARY FOR CUTTING
The tension placed on the blades by the setscrew is another very important factor in the performance of scissors. While too much tension can cause the scissors to require too much work to open and close, if there is not sufficient tension between the blades, the scissors will not cut. We need to learn this, because many of the newer models of grooming shears have adjustable tension dials that allow groomers to loosen the tension. Groomers love this feature, but will often loosen the tension too much and then discover that the scissors are not cutting well (or at all). This is one of the main reasons new scissors are returned by disappointed customers. “They don’t cut well”, is the complaint, when the problem is that they have been overly loosened in a quest for tension-free action. The sharper the edge, such as with convex edge Japanese style shears, the more critical is the exact relationship with bend and tension. There is a smaller margin between too tight and too loose on convex edged shears than with the older style beveled or German edged shears.

HOW TO CHECK SCISSOR TENSION
1. Hold your shears straight up in the 12 O’clock position. Hold the finger ring in your right hand and the thumb ring in your left. (You are not inserting fingers, just holding with thumb and forefinger.)

2. Move the blade with the finger ring to a position between 9 & 10 O’clock.

3. Let go of the finger ring. The released blade should fall by gravity to a partially closed position, about 45 degrees. The blades should not completely close.


USE THE TISSUE TEST
When adjusting the scissor tension, loosen or tighten one or two clicks at a time on the adjustment knob. You can also use the “Tissue Test” to determine if your shears are cutting properly. This is a good thing to do after you have loosened the tension. Hold a tissue in one hand and make full cuts of the blade at a 45-degree angle into the tissue. If the blades are bending the tissue, you have loosened too much. If there is any catching or tearing of the tissue, the blades need sharpening.

A PERFECT CUT!

From the book, ALL ABOUT SHEARS, by Barbara Bird. The book contains
Anatomy of a Shear
Scissor Terminology, (with pictures!)
About Steel & How Shears are Manufactured
Choosing Shears
Fitting Shears
Care of Your Shears
Scissor Performance
Development of Scissoring Technique

ALL ABOUT SHEARS can be purchased at the BBird shopping cart. Click Here to go There!