Choosing the Right Tool
Sharpness is determined by the angle of the cutting edge. The sharper the cutting edge is, the faster the tool dulls. We select the best angle of the cutting edge for its application. Therefore, the shape and type of the cutting edge are of paramount importance in our shears design. Our cutting angles range from 10° to 50° based on application sharpness required.
The edge of the blade is another factor that determines the maneuverability of shears. We always configure the best arrangement of bevel edge angle and its internal side to achieve the best cutting ability by flat grinding or hollow grinding. Serrations are fine lines or teeth ground into the edge of one blade. The serration holds the material, keeping it from being pushed forward.
Fulcrum-type Vampire Tools™ products use a shearing action that starts near the fulcrum and progresses toward the tips as the handles are squeezed. This action creates a force which often pushes harder and thicker materials toward the tips, requiring a sizable opposite force to accomplish cutting. The ratio of the relative distance of the squeezing point and cutting point form the fulcrum, which determines the force and movement ratio. When the squeezing point is at a greater distance from the fulcrum than the cutting point, the cutting force is greater and the movement is less than that applied to the handles.
This has two effects in selection. Relatively long handles provide greater control through less cutting movement and greater cutting force. The latter is often referred to as the mechanical advantage. As the cutting point moves toward the tip, the movement increases and the force decreases. Due to leverage ratio changes, the squeezing force required increases as cutting point approaches tips.
Thinner and narrower blades are less rigid than thicker and wider, plus they must fit between two or three dimensional obstacles without obscuring sight of cut. Excess length may limit maneuverability. Short lengths may produce jagged lines in long cuts due to repositioning between each cut segment. Cutting to the tips will only aggravate the situation. Cutting out intricate decals requires fine, short blades with clear vision of cutting point. In most cases, it is better to roughly cut pieces apart and trim them after. But this is limited by the minimum size that can be held. Dull scissors tear rather than cut. Spring opening can be good or bad dependent on situation and preference. Variation in style and characteristics are common.