Hand Tools Archive

Subject:
Knife steel cardstock cutting bonanza

David Weaver
https://knifesteelnerds.com/2020/05/01/testing-the-edge-retention-of-48-knife-steels/

This from someone on another forum that I came across - I read intermittent bits of it so far looking for familiar things, but I see why some of the knife testing would lead to wanting to put more vanadium in plane irons (even though I think the quality of the edge that lasts a long time on these tests ends up below what we want for smooth planing).

No XHP/V11 on this list, but CTS-204P is on here, which I believe is a less tough but more alloyed version that's similar -the addition is vanadium (3 or 4% or something).

204P outran CPM M4 a little (which is probably expected as we found XHP and M4 in the same ballpark), and both ended up around double the distance cut of most carbon steels - some more - some a little less (this sounds really familiar from our tests!! M4 and V11 wore about twice as long in clean wood as O1)

Most of the other alloys, especially the high vanadium stainless types, etc, aren't really that interesting to us despite their high numbers (fine edge holding doesn't really exceed carbon steel, but ability to hold a duller edge is really great -carbon steels lose the fine edge and then cease being usable pretty soon - the exotic steels lose their fine edge and then continue to go for a long time).

Relative wear of O1 vs. A2 and super blue are almost identical to what we found, except the blue steel tsunesaburo blade didn't wear right and cut itself short. I suspected that if it hadn't shed carbides, it would last about as long as A2 (japanese tool fanatics find this offensive, but the reality is that nothing used in japanese planes has a longer edge life than standard steels of a similar alloy - edge quality and longevity are not totally attached to each other - distance planed was more related to alloy).

I this test, A2 and super blue were about the same for cardstock cuts before dull. Blue super would wear just a bit longer than Blue 1 if the two are done properly (blue 1 has about 1.3% carbon and I suspect the test iron let go of carbides because improper temperature cycling doesn't do anything to incorporate the excess carbon properly, and there will be a lot of it, and maybe to some extent, the bits coming out could be tungsten.)

One last interesting point - cliff stamp did a test with CPM Rex - it didn't have good edge stability. It's a "transition" material, almost carbide. The lack of edge stability caused early failure and resharpening was beyond nuisance. However, in a controlled test like this one, the machine doesn't apparently tax the edge that much and it doesn't fail or chip, so it wins.

XHP is known in the knife world, but it's not nearly as common as the vanadium carbide steels mostly because they are far more common in production knives (likely due to availability). It's not a surprise that it's not shown in this test - it's hard to find at retail and one of the retailers using it about 8 years ago switched all of their XHP knives to S30 or S35.

The conclusion in most knife forums is that even from tests like this, carbon steel knives are antiquated. There's a lot of topical matter on purchasing and testing knives, but the general knife maker subforum is literally empty of any non-archived topics.

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