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Re: M390 sharping and polishing

Fri Sep 21, 2012 12:09 pm

Oh, I wouldn't dump any of the above stones! Just wondering if any of those would work better or worse. I can always get more stones from Mark to add to the collection!

Re: M390 sharping and polishing

Fri Oct 05, 2012 4:06 pm

Well, I got my first taste of M390 today! I roughed in a bevel with an 80 grit belt (the 120 was taking way too long!) and then moved to the Bester 500. Took a while, but I finally got a burr raised. From there, I went to the 1200 Bester until I flipped the burr back and forth 3 or 4 times, then the Rika 5K. From the 5K, I went to my J Nat Ozuka Asagi stone, which left a nice edge. I stropped it on balsa with Boron Carbide or something on it (What was that again Mark?? I can't remember, but it worked nice!!) and it was effortless thru receipt slips and paper towels.

Like has been said, it's not too bad once you get the burr formed. It took a while on the 500, but I don't know if I formed a burr on the belt sander or not and it was a slight convex edge from the belt sander, so I had to flatten it a bit to get the edge bevel going properly. I may break out the Nubatama 150 for the rest of them :) I think it took around 15-20 minutes total to sharpen it with that sequence. I also tried another J Nat (Takashima Koppa), but I liked the Ozuka Asagi better, so I went back and forth a few times with the different finishing stones. It seemed to take a more polished edge and not as much bite as I usually get from the stones.

Re: M390 sharping and polishing

Fri Oct 05, 2012 4:39 pm

I'll just leave this here:

http://belgiansharpening.wordpress.com/ ... ven-steel/

Re: M390 sharping and polishing

Fri Oct 05, 2012 4:52 pm

LOL. Yeah, it was a bit slower going, but once I got to the finer stones, it didn't seem all that bad/different from other knives. The longest part to raise the burr was I had it on 85% of the blade, there was like a 1.5-2" section that took a lot longer to raise the burr on. With the belt sander, the edge was convexed a bit, so I had to flatten that down before I even got to the edge. It may be easier to do these with stones.

I've been eyeing the set of Glass Stones (1K, 4K, 8K, 16K) for these though :)

Re: M390 sharping and polishing

Sun Oct 07, 2012 2:52 pm

Got to sharpen up 3 more today! These went a little bit quicker. I went with a Nubatama Bamboo 150, Bester 500, Bester 1200, Synthetic Blue Aoto, Rika 5K, Shobu San and Ozuka Asagi, then strop. Took around 60 minutes, maybe a tad less to do the 3 knives. I deburred (pull thru before the Rika 5K) and then stropped after the Rika 5K on some composites. The Nubatama worked nicely to flatten out the bevel from the convex grind of the belt sander and the 500 did well, too. Raised a burr a bit quicker than last time. When I felt the burr along the whole edge, I flipped it back and forth once before going to the next stone or deburring so I was sure I had the whole edge bevels meeting. The Shobu San worked much better than I though it was going to, nice bitey edge, but still very smooth. It had that razor blade sticky sharp feeling to it when running across the fingernail.

I think the key to this steel is to use some nice, coarse stones to get the burr formed and then run your normal progression to where you want it. I will try some other stones on the next ones I do (shapton 2K, Henkels 3K/8K, San Aoto, etc) to see how some other stones work with it. May try my coarser J Nats as well, but those are mostly saved for blade roads on KU knives or single bevel knives.

Re: M390 sharping and polishing

Tue Oct 09, 2012 6:16 pm

yikes! just started getting my mo sharpening and then i go and order and M390 artifax. did double time with my shapton 500, 1000 and 6000. NOTHING! wish i had known. at least now i know it's not my lack of skill!

Re: M390 sharping and polishing

Tue Oct 09, 2012 7:29 pm

What do you mean "nothing"?? I have a Shapton Pro 2K and it flew on the steel, only took a minute or two after a 1200 grit Bester stone. If the edge is in decent condition, I would start at the 1000 grit stone and go from there. No need for the 500 unless you are getting chips out, thinning or resetting the bevel. You need to get a burr raised on your lower grit stone. The 1000/6000 jump may be a bit much for this steel, but with the Shaptons, it should handle it. Are you sure you are actually refining the edge itself and not just the bevel? Use a Sharpie Marker to blacken the bevel and then made sure all of the black is removed, especially at the very edge and that your edge bevels are actually meeting together.

I did 10 M390 Artifex in 3 hours after the bevel was set on the belt sander, going from an 80 grit belt on the belt sander. I used a Bester 500, Bester 1200, Shapton Pro 2K, stropped to deburr, then to a Rika 5K, Shobu San or Henkels 8000, Ozuka Asagi and then a Balsa strop with Boron Carbide on it. These had a completely flat edge on them, no edge or bevel what so ever, so I used the belt sander, Nubatama 150 and a 200 grit diamond stone to set the initial bevels. So 180 minutes for 10 knives, around 18 minutes a knife average. I usually spend 10-15 minutes on each knife if I do a full sharpening like that with other steels.
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