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HAP40 first impressions

Sat Apr 26, 2014 3:17 pm

Received my Kohetsu HAP40 240mm about three weeks ago, and though generally happy with it so far, I felt the edge should have been a little better than the way it came OOB.

A week ago I gingerly tried to improve it on a Chosera 5k, but results were unsatisfactory. The edge felt as if it was skating on the stone, and I gave up as I was tired and slightly the worse for wear after a few drinkies. :oops:

This morning, well slept and alcohol free for a week, I decided to have another go, but this time starting on a Shapton Pro 1k.
This gave big improvements, and despite my understanding that these are not 'mud' stones, I had even better results after loosening up the surface with a few strokes of a DMT 10" Coarse plate and NOT rinsing off the 'paste'. Twenty minutes of slow, careful strokes - less on the left side, as the bevel seems to be 80/20 - and I was ready to progress to the Cho 5k again.

This time the stone worked well at polishing out the 1k finish, so I decided to use my balsa strop and 1um diamond spray for the first time. A dozen light strokes on each side, followed by half a dozen on the horses ass, and I have a lethal, razor-edged slicing demon! :twisted:

I decided to skip the 'snow-white' 8k, and it certainly seems unnecessary considering the result achieved.

Very happy :D with all CKTG products so far, and enjoying the learning curve.

Any thoughts on my progression? As a relative noob, expert advice will be appreciated.

Re: HAP40 first impressions

Sat Apr 26, 2014 4:44 pm

Great write up!

I too have had to sober up on occasion before sharpening. :roll:


I am NO expert but your progression sounds great to me. The only "suggestion" I might make is not a criticism, but rather a point to ponder about your progression. I have recently bought a number of stones and rearranged them in my progression to try to figure out what I do and don't like. What I have found is I am leaning toward a 2x to 3x jump between stones. So 1k, 2k, 4k or 1k, 3k, 9k, or mix and match, 1k, 2k, 6k ect. You might consider adding a 2k between the 1k and 5k, you may find it moves you trough your progression a bit smoother.

Re: HAP40 first impressions

Sat Apr 26, 2014 6:08 pm

I'm still new to this sharpening and knife hobby. I have noticed that I greatly prefer a less polished edge. I think 2-4k is a good happy compromise. I was blown away by what a good 1k edge could do. Took it to 5k...got amazing cutting performance but it quickly diminished with use. \

If you enjoy the 1k then you should order an Aoto from Ken. It's got the toothy bite of a 1k with a more a little more polish and refinement. I think I might stockpile Aoto's for the apocalypse.

Re: HAP40 first impressions

Sat Apr 26, 2014 10:15 pm

I have a similar experience with the 210 hap40. Ootb I tried just a few edge trailing strokes on a 5k rika, which was doing nothing positive to the edge. I sobered up and 2 days later started with a shapton gs 1k, got a crisp , as close to perfect an edge I couldget. Used the rrika then stropped on leather with half micron diamond. I found the edge was much better at 1k. So I started over at 1k, made a slurry on the rika and sprayed some diamonds on it and simply stropped. Sickly sharp edge! Much better bite and retention.

Re: HAP40 first impressions

Sat Apr 26, 2014 10:48 pm

seabell wrote:A dozen light strokes on each side, followed by half a dozen on the horses ass, and I have a lethal, razor-edged slicing demon! :twisted:

When my knives are this sharp, which is more often that not, I'm guaranteed to get cut, at least once, while using it. :D
It's like, if the knife is that sharp and you pick it up...you will get cut.

Maybe not a big cut, but a cut nonetheless.

Re: HAP40 first impressions

Sat Apr 26, 2014 11:20 pm

Thanks for your responses!

Cedarhouse and Umberto: Your suggestions are appreciated and I will consider - but I really don't want to buy more stones than I actually need. I want a lot of other toys for my playroom, and my sous vide circulator should arrive next week. Then I want one of those nitrous oxide whipping things, and, and... :roll:
The Aoto is the blue 2k, yes? Maybe. I'll certainly consider it, but I like the convenience and durability of the Shaptons.

Jared: Interesting observations. I'll see how the edge performs and maybe try your way the next time this thing needs touching up - though that may be quite a while if all I've read is true about this steel.

Desol: I hear you my friend. This knife hasn't got me yet, but the Tanaka petty I bought at the same time bit me early on, when I somehow managed to nick my palm with the heel of it!

Re: HAP40 first impressions

Mon Apr 28, 2014 7:18 pm

Used the freshly sharpened Kohetsu HAP40 this weekend, and noticed something I don't understand:
When the knife was in new, OOB condition, I was perplexed by the way potatoes seemed to weld themselves to the side of the blade when quartering. I mean they really stuck on there like limpets.
Now, after bringing the edge nearer to what I expected, I noticed that when I sliced a couple of potatoes - from the same bag as the sticky ones - that they did not stick at all. In fact I was able to leave a halved spud on the board and slice it all along, and it just sat there, still looking like half a spud. Only when I swiped it did it reveal the 1/8'" slices. :shock:
So, can sharpening - edge only, not thinning or any other refinement - really do this? The difference was night and day, and I am wondering if some other factor might have been the reason (phase of the moon, relative humidity, divine intervention etc.)

Re: HAP40 first impressions

Mon Apr 28, 2014 8:30 pm

Seabell - that's an interesting observation - I'm curious as to any answers you get on the stickiness issue.

Re: HAP40 first impressions

Wed May 07, 2014 11:02 pm

Seabell, I've had the same issue with potatoes welding themselves to the right side (the flatter-ground side, I believe). I ordered a DMT plate for the Edge Pro; I was thinking I might try to put a starker bevel line about 1/2 inch up off the edge, sort of like my Moritaka. I've heard that that can help with stiction (the Moritaka is thicker than the HAP40 but has no sticking problem). Now I'm wondering if I just need to sharpen again...

Re: HAP40 first impressions

Thu May 08, 2014 1:34 am

seabell, my only guess as to your sticktion findings are, a) the blade was very polished on the front bevel when u got it, your sharpening revealed some less polished scratchs and are now aiding in food release... yes sometimes a little is a lot, or b) again in sharpening you probably created just enough convexity to the edge to aid in less sticktion... again a little can do a lot... you are a freehander and as much as all of us would like to be consistant we are humans and still wobble slightly creating a more convexed bevel even if hard to see with the naked eye... so unless you've got the steady hand of the bullman whose bevels look like they were cut with a laser guide... that's probably the combination of factors that have caused your end result...
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