Have you used other high speed steels? If so, how does HAP40 compare to it/them?
Hey guys, I checked this thread because I wanted to see if anyone was reporting any results of their hap40 usage and, sure enough...
I received a Hap40 Delica a couple of weeks ago and have done some sharpening and testing on 5/8" hemp rope. I have carried the knife as an "edc" the whole time but honestly, outside of fish cleaning I just don't use my pocket knife too much so it takes me a long time to build even a rough idea of steel performance. What I can pass along is my experience so far in sharpening and rope cutting.
Hap40 sharpens to a very keen edge with minimal fuss. A microbevel takes it to screaming sharp in just a few passes and it seems to be more forgiving to my technique than steels like s110v and s90v. I haven't polished the edge yet but given how sharp this steel gets off a 1200 dmt I am confident that it can be taken to hht sharpness with another 60 seconds of refinement. I am able to get a bit higher level of initial sharpness out of m4 than I am from s90v/s110v, and a hap40 easily goes to the next level beyond that. I'd put it more in line with Hitachi's super blue in ability to take high level sharpness.
As far as rope cutting, I have only done one test and it isn't much like how jim does his tests so I'm not sure if anyone will find this useful. Rather than trying to test to a determined level of sharpness (or dullness) I make a large number of cuts with two knives and measure sharpness after the cutting. In this example, I compared the hap40 Delica to a Manix 2 in s110v. Both were finished on a 1200 grit dmt and both would grab beard hair on contact. Well, the s110v would grab and the hap40 would bite into it like a pitbull. I tried everything to get the s110v to that exact level and just couldn't quiiiiite get it there so went ahead and ran the test. What was immediately apparent was that geometry was going to make the test unfair. The Manix is much thicker stock and thicker behind the edge than the thinly ground sprint run Delica (thinner even than the standard Delica I believe). There was a notable difference in force and pressure required from the first cut that was obviously due to blade geometry.
I used 5/8" hemp and would make a 4 slice motion...forward/back/forward/back. I could easily cut the rope with one motion but I'm trying to create wear as quickly as possible so i do the sawing motion. After 80 cuts (which is 320 back and forth motions) I tested the two steels. The hap40 edge had significantly more bite. Both would still shave but the s110v required more pressure...almost scrape shaving. Both would still cleanly slice magazine paper but the hap40 made a significantly cleaner cut. The s110v wanted to snag just a tiny bit in a couple of places.
FWIW, I have tested s30v in the same way and both of these steels outperformed it. I have also done the same testing with an m4 custom (Gayle Bradley Flipper) that is ground to .010-.012 bte. M4 at that grind was comparable to the more thick s110v blade but under performed the hap40 Delica, which though thinly ground is still thicker than the m4 custom.
My thoughts on this steel so far are very favorable. I like high edge retention and wear resistance but not at the cost of ease of sharpening and initial sharpness level. That is why my preferences sometimes lean towards the slightly less wear resistant steels. I believe this is the best steel I have used as far as giving great edge retention while remaining very easy to bring to high level sharpness. One of my favorites for this combination of qualities has long been m4 but from what I have seen so far, hap40 outperforms it in both areas. It is capable of achieving higher initial sharpness (given my ability and protocol) and so far is showing better edge retention.
This thread has helped me buy some of the best knives performing knives I have ever owned. 
