Differences among steels in edge retention slicing harsh/used cardboard


Introduction

A Street Beat in VG-10 from Spyderco was being used as a general utility knife and the performance was observed to be very low in regards to edge retention on cardboard. Specifically, as a general observation, the knife was cutting about 1/10 of the expected amount of that type of cardboard (1/8" corrugated stock). Now there are two main possibilities :

The simplest way to determine this is to use another knife (or knives) and see how they compare on the same cardboard.

Method

A number of knives were used to slice the cardboard with the following method :

Results

Immediate observations :

In addition there was a tremendous difference noted in the ease of grinding. Towards the left the edges on the knives were reset in as little as 25 to 50 pps. However towards the right this increased to ten times as much. This is most likely due to the rise in volume of very hard carbides which can wear the alumina ceramic in the sharpening stone and the bond of the stone is too strong to release abrasive under the pressure used ( < 5 psi) .

Discussion

The majority of the knives used have very similar geometries and specifically have edges of 6 to 8 dps. However There are two knives in this comparison that likely show the effect of a slightly different angle.

The Perrin likely has a slight reduction in edge retention due to the higher edge angle and the cKc utility in H13 likely has a slightly higher edge retention 1 as the edge angle likely falls into the sweet spot of edge retention for this material where it has just enough strength to keep from quickly deforming/rolling.

Recap

More extended commentary can be seen in the forum thread :

References

1 : Apex bevel angles influence : VG10 and S30V (hemp)


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Written: 30/07/2015 Updated: Copyright (c) 2015 : Cliff Stamp