Bevel angle vs sharpness

[Ken S]

Caveat: This is largely based on opinion rather than documented evidence. That said, With router bits, carbide bits stay sharp longer by a very wide margin than high speed steel cutters. However, new hss bits could be sharpened more keenly than carbide. The choice was higher initial sharpness which was shorter lived, or slightly less sharpness which holds up for a long time. Longevity generally carries the day; high quality hss router bits are rare today.

Lie-Nielsen used to make bench chisels in both O1 and A2 steel. Once again, the longevity of the A2 steel edge seems to have carried the day over the shorter lived sharper edge of the O1. O1 bench chisels are no longer listed in their catalog. A2 chisels are generally sharpened with a 30º bevel, whereas O1 are generally ground to 25°. In the past, much of the quality of a chisel depended upon the skill of the heat treatment. I do not know the answer, however, I wonder if A2 is less dependent upon skilled heat treatment, and, therefore, less costly to manufacture.

Not all woodwork requires the same level of sharpness. A finish cut on a delicate carving is much more demanding than chopping out a mortise or dovetail.

Thanks for bringing up an interesting topic. I look forward to more dialogue.

Ken