Bidinger B-Grind

Hm, difficult to answer. I've never heared about an Idahone. Is this a stone that stems from Boise, or so?
I don't have experience with the steel (although what I read here seems extremely promising), nor do I know about the quality of the heat treatment of the actual knive. Nevertheless we typically were pretty reluctant to use a diamont based abrasive for finishing an edge, let alone a rather coarse one.

But You did ask for the recommendation for a touch-up, and not for the initial care of the knife. So I think, that - if the knive was still in a rather good shape - I'd try to start the touch up with the 6k stone. But then I recommend to continue the touch up with a non-diamond based hone.

Stropping it with a diamond loaded leather might be worthwhile for a fast touch-up, if one really has no time to do a traditional touchup using stones.

I also have to confess, that I am not fully convinced in _not_ using something as a 3..5k synthetic stone as the primary stone. There are lots of good stones available in that range, which are perfectly suited for a touchup done by hand (rather than an aided one). One could even have a Shapton Pro 2k as a primary touchup stone (if one resists in doing too many or too heavy strokes). So I am not in the position to choose one of Your options. But I tend to think, that this knive should be a pretty capable one...

Best regards
Peter

PS: If one were willing to let the stone dry for a few days, than the Suehiro Rika 5k is the best stone in that range. I find also the 8k Kitayama a very attractive stone - but an 8k stone needs a skilled sharpener unless one uses a system. There is a great 3k Naniwa Pro. All of these are very suited for a touchup of Your knive.

Well, do You've got a microscope or at least a good loupe? You might try Your stones and have a careful look on the result. The pragmatic approach isn't the worst one more often than not.

If the knive manufacturer recommends a diamond based hone, then it is valid to consider one. :-)

best regards
Peter

I saw this one on Instagram the other day and thought it was looking nice, clean and very tempting….

Hello,

i recommend for steels with carbide content like this one the following:

You may sharpen it as usual till the finest stone. Bevor you finish take a matching diamond hone/ Lapping Film and after this clean the edge with an even finer synthetic and a natural stone after this process.

For MC390 (with matching V content) i recommend (on systems):

-DMT325/Progression with Shapton Pro till 12k switch to DMD 12k or 1my Dia Lapping Film followed by Shapton 30k and Nakayama/Arkansas (depends on cutting style pull/push)

Greets Wastl.

OK, so I have to admit, I went against all recommendations

I was asked to try the edge, and see how long it lasted, so I went with the "least invasive" option first - leather stropping with a little 1m diamond spray.

Use: all meals for a 4-person family for about one month, plus several cases of apples on plastic boards for a cider pressing event. This also involved leaving the knife wet for a couple hours - no problems with stainless properties.

Findings: The heel started with a toothy edge out of the box, and retained that for past month. The belly had a tiny burr to start, which I quickly removed on a soft Arkansas stone (2 strokes). Otherwise, no stones used. The belly cut tomato skins until the cider event. After stropping, it lasted another week until finally becoming a bit smooth. Still push-cuts newspaper from the edge, and slices rolled-over newspaper. I think a really clean edge would last a long time based on overall use, and how it responded to stropping.

I've taken some video over the past month, and will start editing it together this week to omit the boring bits. After that, sharpening on the 6k diamond and start the edge-testing all over next month.