Never start a freshly sharpened knife on hard stock, the keenly honed edge will dull the edge prematurely or chip it. as much as 50% of edge life can be lost on the first cut. always start a fresh knife on soft stock , tissue or napkin stock is best, vellum or envelope stock works too. If all you cut is hard stock you must condition your edge with a soft piece of wood or an old used cutting stick by rubbing it along the edge several times. better yet let your regrinder know that all you cut is hard stock and they can pre condition it for you.
Knife bevel angles Most knife angles used today are too steep or fat generally from 24 to 27 degrees These angles were developed 30 to 40 years ago for more dense thicker papers, made from virgin fiber which were much more solid than today’s papers. It has been our experience that stocks high in recycled fiber tend to dull knives faster. Recycled fiber tends to be less dense but more abrasive, this could be because they add more fillers such as clay or other fillers to give the stock stiffness or body, the shorter the fiber the less stiffness it has. A paper fiber that has been recycled many times has a very short fiber and requires more fillers to give the sheet stiffness and body plus bursting and tearing strength.
Inspecting your newly reground knife Always drag a soft cloth or piece of cotton over the edge to check for burrs or small nicks before installing the knife. If you have had problems in the past with not cutting the last sheet in the lift where the ends cut first, you could have edge bow, this is a regrinder problem. [get a free grind] you should never have to shim a stick up.
A flat bowed knife can be difficult to install and dangerous, return to your regrinder for straightening. Inspect the back of the knife to be sure there is no back bevel or shinny spots, back bevels can cause premature knife draw or pull. Paper knives should have a perfect chisel edge.