Twelve years ago I started using a standard test to test the cutting abilities of different knife steels. All the blades I prepare for this test are the same size, shape and thickness, being .125 in. thick and flat ground. The included angle is 12 degrees to 15 degrees, with a primary sharpening angle of 15 degrees per side; final sharpening is on a Norton Fine India stone. Cuts are made on the single strands out of a 1 1/4 in. hemp rope. The single strands are easier to handle.
Three tests were conducted on each blade and the results averaged. Using a slicing cut, the strand is parted and cutting continues until the cutting edge loses its bite into the rope. This is about the same point that the edge loses its ability to shave hair.
|Rockwell "C" Hardness||Number of Cuts|
|154 CM Freeze treated||61||44|
|154 CM Not freeze treated||60||38*|
|ATS 34 Freeze treated||60||38|
|440-C Freeze treated||58||33|
|440-C Not freeze treated||?||25*|
*Note the difference that two points of Rockwell hardness makes, also the loss of edge holding when freeze treating is not used.
There is a lot of difference in rope; some is more abrasive than others. I keep a standard knife on hand to compare all others to; this will tell you also when your rope changes.
W. L. Goddard