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Lefty Spare Blade for KUM Left-Handed Sharpeners, 3 Blades
Lefty Spare Blade for KUM Left-Handed Sharpeners, 3 Blades


Quantity in Stock:29
Availability:: Usually Ships in 24 Hours
Product Code: KUM 801.09.11

pare Blade for KUM Left-Handed Sharpeners. KUM 3 Blades. Three (3) high-carbon steel cutting blades feature Dynamic Torsion Action. DTA handles the difficult dual task of cutting hard graphite while shaping soft wood -- remaining rigid when required.
  • 1. The blade is hard.
  • It is made of ultra-hard high-carbon steel, which can cut stone, since pencil leads are made of a mixture of graphite and various types of clay, some of which are often used as abrasives. The steel used in KUM? blades has a carbon content of 62 hrc. more than ball bearings (55 hrc.), for example, or high-quality knives. Blades last for thousands of sharpenings on normal pencils. Harder leads (H, 2H and harder) require more frequent blade replacements.
  • 2. The blade is sharp.
  • Each blade is razor-sharp. A felt sharpening wheel (similar to the leather strop) is used as the last step in the automatic sharpening process. Note: stainless steel cannot be used because it cannot be sharpened enough.
  • 3. The blade is curved, not flat.
  • Acting like a spring, it exerts constant upward pressure on the screw, which keeps the screw from loosening. As it is cutting the pencil, the blade weaves slightly up and down, dynamically adapting to the fibrous structure of the wood instead of ripping straight through it. The cutting friction is reduced, and therefore the pencil is easier to turn. This happens because the blade, made of carbon steel, is tempered and therefore flexible; its curved shape causes it to act like a spring pressing up against the screw that holds it in place. The tension thus created gives the blade its dynamic characteristics. KUM calls it the Dynamic Torsion Action.
  • 4. The blade is rust-protected.
  • High-carbon steel normally rusts quite easily, so three elaborate operations are used to protect every KUM blade: 1) polishing; 2) ultra-sonic cleaning: 3) coating with oil. This protection lasts for years except in warm climates with high relative humidity, where minute rust dots can form after six months. A stainless steel blade cannot be used in a sharpener because it cannot be sharpened enough. Rust does not affect the performance of a sharpener, which is constantly used, since the sharpening action keeps the cutting edge clean.

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