sharpening - where to start w/ a new knife?

[scottf2]

Hi all. I recently purchased my first Japanese knife (a 240 mm Hiromoto HC Gyuto) and I have a couple of questions about achieving optimal performance from my new knife.

I've read a number of threads which imply that these knives do not come from the factory with the optimal sharpness that they're capable of, and I'm wondering how to achieve that level of sharpness - in other words, where should I start? I purchased a Sharpmaker, and am considering getting an EdgePro for the holidays - I've used the sharpmaker to try to "improve" the edge on my knife, but it doesn't seem to have too much effect - basically, out of the box the knife could slice notebook paper, but not push-cut it, and after about ten minutes of sharpening with the sharpmaker (using the recommended process from the DVD, going through all four courseness levels on the stones) it's not much sharper than that. I've been reading threads about knives sharp enough to shave easily, or push cut newsprint, and my knife is certainly nowhere near that sharp.

Is that level of sharpness achievable by an inexperienced sharpener using the Sharpmaker? If so, does anyone have any tips on how to get there? Should I be using the 30 degree setting first, and then the 40 degree setting to finish off the edge (as described in the DVD and instruction book)?

Am I likely to achieve significantly better results with the EdgePro, or is it just a matter of practicing with what I've got now?

Thanks for any advice or guidance anyone has to offer - I've greatly enjoyed reading the posts in these forums and have already learned a great amount!

Thanks,
Scott

[watercrawl]

Wow, this isn't going to be a quick answer question.

I don't think that the Sharpmaker has a high enough grit available to get a super polished edge that allows that "scary sharp" edge. I also don't think that 30 degree primary and 40 degree secondary bevels are optimal for the edge you're looking for either. That's probably the biggest disadvantages with a system like the Sharpmaker. Now, I've never had one, so I'm going purely off knowledge and not use.

The EdgePro comes with some blanks that you attach their polish tapes to that can get pretty darn good edges with. You can learn to use this system very easily and get very good results. You can even use their blanks and put some third party polishing film on them and get a very, very nice edge. You can also get a much lower angle with the EdgePro.

But if you want that elusive edge that pops standing hairs, you're going to need something finer. Whether it be super fine sandpaper up around 0.5 micron (30,000 grit) (you can also attach this to the EdgePro blanks), a stone (pretty expensive for the high grit stones), or a leather hone charged with compound (available from handamerican.com).

Now, I'm just talking about the final polishing steps. What you've done up until then is actually more important. Getting a consistent bevel along the entire edge. Making sure you've got a good burr at all grit levels. Making sure you get rid of those burrs before you proceed. These things are more important than the final polishing step. But, you can also easily screw things up pretty bad at that high of a grit level. If your hand wavers much when you're polishing, you can round your edges pretty easily.

Wow, I've just scratched the surface of a proper answer. One of the best things you can do is to either get Murray Carter's DVD or the sharpening video from Korin. These are great teaching videos and explain some basic principles.

[scottf2]

Thanks a lot for the reply. I'm pretty sure I'll be picking up and Edge Pro soon, so we'll see how that works out!

A few more questions - you said:
"I also don't think that 30 degree primary and 40 degree secondary bevels are optimal for the edge you're looking for either. "

What do you think the optimal edge angles would be for my purposes (ie: general kitchen use, on a plastic cutting board, mostly slicing/chopping veggies)? If I do end up getting the Edge Pro, I notice that it comes with a DVD - does that provide any information about how to pick bevel angles? Do either of the other DVDs you mention cover that?

Thanks again for helping with my continuing education

Scott

[watercrawl]

I think maybe my previous post dwelled too much on the angles. I don't think the angles should be your first concern, the grit should be.

But, to answer your question:

Many people, me included, like to get silly and go down to 10 degrees per side (20 degrees total) for the primary and 15 degrees for the secondary (30 degrees total) if a secondary bevel is even put on. This low of an angle isn't necessary and at 15 & 20 degrees you can still get a very sharp knife, I just don't think it cuts as good and never really provides that elusive "scary sharp" edge I'm after. I actually like 15 degree edges for the knives my wife use, they hold up pretty good to her abusive ways and are still good enough to cut nicely. But, I really like the 10 primary & 15 secondary degree edges myself.

However, I think the more important thing is getting something finer to finish the edge off with. If I recall correctly, the finest rod in the Sharpmaker is equivalent to like 1500 grit on a Japanese waterstone. Anything lower than 2,000 grit is really meant to be cutting metal away and getting ready to polish rather than polishing, IMHO anyway. You start getting into the 4,000 grit and higher and you're starting to polish and get that edge that will impress you arm hairs and your fingertips.

As for the DVD's, I have watched the Carter DVD and the one that comes with the EdgePro and I cannot recall anything in them that talks about what angles to use for what. Well, then again, they do talk about it somewhat, but I don't think it was in detail. The EdgePro one might talk about a range for kitchen knives or something along those lines, but I don't recall well enough to say for sure.

[scottf2]

Great - thanks again for the thoughtful replies - I'll keep you up to date on my progress in arm hair removal

[Grouch]

I've read that the sharpmaker's extra-fine rods are ~4000 grit. There's a table somewhere (I'm sure Pam has a copy).

[yuzuha]

To start, I doubt the knife's angles are the same as the sharpmaker's (that 40-30 stuff seems more appropriate for outdoor knives and the like anyway), so you probably are just scraping the side of the bevel somewhere with it. Are you sure it has the same angles on both sides? Some double sided Japanese knives come with 70/30 or some other ratio bevels, and you can't do those on a Sharpmaker anyway (I only use my Sharpmaker on my Wushof's and Hecknel's... the 30 degree setting sharpens those up nicely, though I think they come with something closer to 22-25 degrees).

Generally, what I do is grab a 2k or 5k waterstone (depending on how sharp it seems in the first place) and sharpen it up a bit using the existing angles (you can rock the bevel on the stone, or sometimes go by visual clues in the water, to tell when the bevel is flat on the stone and just use whatever angle that is without caring what it is). If the edge seems too fragile, then I may drop back to the 1k and raise the spine just a smidgen and give it a slightly thicker bevel, but mostly I haven't had to do that.

Grouch, I have a table of waterstone grits (Shapton, old JIS standard and current JIS standard, Norton and DMT http://members.cox.net/~yuzuha/jisgrit1.html but bond makes a difference too since, while Norton says their 8k actually uses abrasive of a size equivalent to Shapton's 4k, everyone says it actually leaves a finish somewhere between the Shapton 5k and 8k), but it doesn't have sharpmaker rods in it... think that was CBWX34's spreadsheet.

Here is a photomicrograph of the Sharpmaker ultra-fine (comes with the medium and fine rods so I ordered a set of the ultra-fine too)


(25x objective, about 1,400x total). There are some larger and quite a few smaller (plus the tips of larger grains poking out of the matrix), but the majority of the larger grains appear to be around 2,000 grit JIS. But they are rounded and held tightly in a very dense matrix so they do not cut at all like a waterstone. Instead, they burnish like an orange stick on modelling clay, and, also like smoothing clay with a stick, the rods seem pull loose little balls of metal and smear them over the surface and leaves a finish that looks like this:



Leaves the burnished part nice and bright the surface isn't exactly smooth. Here is the same hunk of metal that I polished on a Naniwa 10k at a right angle to the sharpmaker that exposes the gouges made by the balls of metal the sharpmaker pulled up:


Anyway, while the UF rods are probably 2k-3k grit abrasive, they do seem to leave a 5k-8k finish in the smooth burnished parts (the gouging/streaking makes them unsuitable for polishing the sides of blades but that should be less of a problem on a thin edge bevel).

[Pal]

I have a question. Which waterstone relative to the abrasive grade tears and wears faster and used up more? Is it 1000, 3000 or 6000?

[Fred]

I have a question. Which waterstone relative to the abrasive grade tears and wears faster and used up more? Is it 1000, 3000 or 6000?

Always the coarser grit. Your list goes down in coarseness. The sharpmaker is useless for traditional Japanese knives. Best get a waterstone or two. 1000 and 6000 would make a good pair. Combo stones with those grits are even availalbe inexpensively.

[scottf2]

Thanks for all the suggestions - I'll relegate my Sharpmaker to use on my German knives, and pick up either the Edge Pro or a set of waterstones for the Japanese knives... I'm sure I'll be back soon looking for advice on using one of those sharpening methods

Thanks,
Scott