Mon Nov 05, 2012 4:13 pm
I'm really looking forward to buying the Richmond Artifex M390, but I heard that M390 steel is really really hard, how would you sharpen this knife? Shapton Pro Stones or should I start with Diamond "stones" and progress to ceramic stones? BTW I sharpen knives free handly.
Mon Nov 05, 2012 4:14 pm
The Shaptons will cut this metal just fine. It just takes a little longer. Diamond plates will speed up the work but they're not critical.
Mon Nov 05, 2012 4:54 pm
I sharpened up 30 M390 210mm Artifex recently. These had a completely flat edge at .020" thick. I used a belt sander and 80 grit belt to rough in the bevels. From there, I went to a diamond plate to refine the edges a bit. Once the bevels were set and meeting in the middle of the edge nicely, I went Bester 500, Bester 1200, Shapton Pro 2K, Rika 5K, Shobu San (8K) and Ozuka Asagi 12-15K. The last 2 are Natural stones and I used 1 micron diamond spray on them to help with the slurry. All of these stones worked fine. I tried the Nubatama 150 stone and it worked, but was a bit slower compared to the diamond stones, but left a much finer finish. Even the Bester 500 worked reasonably fast for a 500 grit. It sharpens nicely, but may take a few more minutes on each stone. If you want that perfect mirror edge, be prepared to spend a long time on it. If you want an awesome kitchen knife edge, it isn't too bad, maybe 20-30 minutes to run through the whole setup if there is already any sort of an edge on it.
Mon Nov 05, 2012 5:13 pm
It's not so much that the steel is "hard" it's that it's very wear resistance...that's why it should (I'm just a lowly home cook so edge retention testing is hard for me) maintain it's edge longer than most steels.
This wear resistance is what makes sharpening them a chore, but you should have to do it less often.
If you would ever need to thin a knife with a steel like M390, you would want something rather coarse....Shapton 320 or so....but you don't need diamonds. Diamonds make things go faster at first, but often times the deep scratches they leave mean you'll spend longer taking them out later.
Mon Nov 05, 2012 5:42 pm
I agree with Adam. The deep diamond scratches were why it took a bit longer on the 500; I knew I wanted to get those out with my first waterstone, otherwise it would take forever! The Nubatama 150 stone worked well for that, too, but was an extra step between the Diamond plate (cheap Harbor Freight 4 sided block) and the Bester 500.
The Shapton Pro 2K worked really well on the steel, so the Pro series should work nicely on it. MadRookie loves the Glass Stones for M390.
Tue Nov 06, 2012 1:22 am
I understand why some dislike diamond hones but with vanadium carbides @ 82 Rc they are needed.
Tue Nov 06, 2012 4:12 am
Not unless you are doing major reprofiling/chip repair on the M390. Maybe 1 coarse diamond stone/plate for that task, then a good 500 stone to remove those scratches. When I did the 30, I only used the diamond to refine the 80 grit belt edge and get the bevels meeting. You do not need diamonds for routine sharpening tasks. I even used fine J Nats to sharpen M390 w/o a problem; I only used the diamond spray to build up a slurry because the 2 stones can take a while to do so.
Tue Nov 06, 2012 7:44 pm
Before I sharpened kitchen cutlery I was known for using diamond hones and sharpening premium, high wear steels. I don't make posts like my previous one just to think out loud.
Tue Nov 06, 2012 7:53 pm
I understand, but from my experience with m390 in knives, diamond stones aren't needed once an edge is established. I used several different stones that worked well and others have reported other stones worked well, like the Glass stones. For coarser work, diamonds work much quicker, but for what the majority of people will be doing with general sharpening they aren't needed for m390.
Thu Apr 04, 2013 11:49 am
How is the factory edge? is it very thick, requires thinning OOTB ? I have seen an Ultimatum m390 spine shot on the other forum
looks like old school extra thick blade!
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