Hi Matthew,
The grit issue, it's complicated. The official government standard is JIS6001-1998, and that's what most stones made since that time are graded to. But King are old, and to maintain consistency over the years, they stuck with the older JIS6001-1987 which has been unchanged for decades previous to the official standard created in 1987. The difference ranges from 20-40% coarser over the range of grits found in sharpening stones for the older standard. Shapton use the old standard as a basic reference, but self impose a tighter tolerance in grit size and maintained it for the Glass Stones that are only a few years old now. Norton use the old standard, but lose their way towards the finer end of the scale. Most of the newer stones use the newer standard of course. Sigma Power uses the new standard across the boards, which leads me onto something else, speed.
You said "Choosing the one with the fewest strokes could just as easily mean you have chosen the coarsest of the '1000 grit' stones. ", and that's not even close to how it actually is. Take 3 stones, the Naniwa Superstone, The Sigma Power ceramic and the Sigma Power Select II. All of them are genuine JIS6001-1998 #1000 rated stones. The Naniwa is resin based, requires no soaking so it's "user friendly" but has little cutting power and is very slow, but gives an impeccable finish and stays admirably flat. The Sigma ceramic is fired like a bathroom tile, requires soaking and is composed of Aluminium oxide with a ceramic binder. It cuts quickly, stays very flat and is nearly silly person proof. You just use it, and it keeps working no matter what you do to it and how abusing you might be to it. It stays exceptionally flat and cuts much, much faster than the Naniwa. The Select II is composed silicon carbide compressed and fired into a semi-homogeneous brick. There is no binder, only abrasive. It needs a soak, and the surface breaks down faster than the Naniwa or Sigma ceramic, but because it uses harder SiC abrasive and replenishes the abrasive constantly, it's faster than anything else out there for the same grit size and finish on the tool.
So, the Select II is the fastest, case closed? Not quite. Because the SII was developed for HSS and similar tough alloys, the way it works allows those steels to be abraded very, very quickly. But it's dumb in that it can't tell the difference between tough Power metal HSS (HAP40, XR7, CPM-M4) or easily sharpened white steel/kamaji (wrought iron) so it 'goes out of flat' at the same rate, regardless of the steel.
However, the slightly slower in speed but much harder Sigma ceramic wears very, very slowly so stays flatter in use, has good enough AlOx abrasive that it will still work with most any steel available at a good rate, but milks the abrasive in it for every bit of goodness. Because it's porous, any swarf can duck into the stone preventing clogging and any water will be pushed into the stone (reverse osmosis?) so tools won't skip and slide. Because it's a very hard stone, it has no feeling, but you can push it incredibly hard without harming it at all. Heck, they're functionally indestructible only worried by large hammers.
The Naniwa, the slowest of this three speed wise has trouble with tough steel, but can work if you're patient. Because the abrasive is milked for everything again, it wears very slowly, but because the abrasive is softer and more fragile than the AlOx in the Sigma ceramic, it breaks down and leaves a finish on the tool that cannot be rivalled. The stone is 'soft' in feeling making it easier to use but because the binder holds the abrasive like it's gold, you do get clogging and tools can skip on the stone as well. Nice stone, but only if you have simple steel.
For me, I prefer the Sigma ceramic and I can argue that it's the winner not because it's the fastest or easiest to use or flattest, but because it's the Keke Rosberg in the test. Does nothing really exceptional, but does nothing poorly either. In fact, I honestly believe it's the best #1000 grit stone commercially available today because it does everything well and has no real Achilles heel. Just an honest chunk of bathroom tile that won't quit or fail you.
I could argue the Select II is the winner because it's blindingly fast, all the time. But it dishes, it's expensive and won't last so long, but it's fast, fast, fast! Is the Naniwa the winner, doing all the heavy lifting at the #1000 grit level and being nice and easy to use? Possibly, but not many would agree because it's a slow stone.
Speed isn't everything.
(And if you want speed at this level, Sigma make a massive #700 stone in the same style as the Select II. Similar to Norton/Shapton/King #1000 in grit, but orders of magnitude faster. I pull that one out when I need to grind down mountains.)
I have plans to make up a proper grit chart soon, and will be updating things a little with regard to stones. I hate mystery and myth, preferring evidence and results. I know #1000 grit stones intimately, but can only offer opinion in other grit grades for now. Not saying I don't understand them too, but have no hard evidence to back it up.
For a description of JIS6001-1998, check this. ->
http://www.fujimfg.co.jp/benri/kenmazairyudo1.htm
It's all in Japanese, but if you can work it out, it gives the size of abrasive as well as the allowable tolerance according to the standard. It's the best example I know of, and matches my printed paper version which is the standard. No fudging.
I've been criticised for doing full bevels on all the tools, and I won't bite. My reasoning for working the full bevel was not because I prefer to sharpen that way (I do, I have my reasons) but to present the maximum amount of steel and push all the stones as hard as possible. I could have used microbevels, and you'd see graphs like a flat plateau which don't tell any story at all. It's also difficult to be consistent with a microbevel with regards to how much steel is on the stone. Using the full bevel face, the amount of steel is relatively consistent across all stones so they need to do the same amount of work as each other.
I know you're not criticising at all, but it's been said many times that one could use a microbevel and be done quickly. If that were the case, then they'd all perform relatively quickly and we'd learn nothing useful.
The really telling one is the laminated white steel chisel. Blunted in the same was as every other tool in the test, it was bought back to a usable edge so quickly that I'd have to count individual strokes, which makes differentiation between the stones nearly impossible. So it got blunted by a much larger amount.
The blades I used were all 'off the shelf' and the same for each stone. There are always variances in blades, but by using only one blade in the test, and none of them 'new', the steel should be consistent for the entire range of testing. By testing each stone 3 times with the same tool, it further reduces the chance of their being some soft/hard steel and while someone else's blades might be harder or softer, the results of their own testing should be similar.
(Note, Lee Valley have also done a similar test of #1000 grit stones, and had slightly different results. I had nothing to do with their testing, and can't agree 100% with their findings either.)
I use flat bevels on chisels because I like to be able to use that bevel face as a flat reference when paring. Because it's short, there's less effort required to keep it flat or to make it flat initially. Because there's a fulcrum not 1/2" back from the cutting edge, I can lever out of the cut easily if it bites in too hard. I refuse to spend too much effort flattening a back that I need to subsequently protect from harm for the life of the tool, much preferring to make sure close to edge only is smooth and relatively flat and finely finished. If I screw up the flat bevel, it's easy to make a new one. Screw up a flat back, and you're in for more time and effort than I have available to repair it. Yes, my chisel backs
are flat, but I'm not fanatical about it. That's just me though, and I don't expect anyone else to take on my own preferences blindly.
It's also why when someone asks me "which stones should I get" I always ask what steels they have, how much steel they're putting on the stone and if they know, how they want the stone to perform. Without that knowledge, no stone or any stone could be argued to be 'perfect', I pocket their cash and leave them to work out why they can't get their tools sharp in a manner they'd hoped for. I can't do that and sleep well at night. It's also why I have so many options available in the way of stones, because not everyone wants what I want out of a stone and not every/any stone is ideal for every purpose.
I think that you've found that yes, the King stones will work with your Fujikawa XR7 chisels, up to a point. What's actually happening there is the soft backing steel (not wrought iron) is readily abraded by the stone with little resistance. The stone efforts are then focused on the hard steel, and I'll be blunt here (hah!), it's out of it's depth. The steel is almost as tough/hard as the abrasive in the King stone, and it's not so much abrading the hard steel as tearing it. Some abrasion will occur, but the very hard carbides and nitrides in the steel are harder than the stone's abrasive. The tool will become sharp all the same, but the difference between one of those chisels sharpened by a series of King stone and the same chisel sharpened with a similar series of Select II (made for the job) is like night and day. The 3M films work well on those chisels because the abrasive is up to the job. Diamonds work well because the diamonds are harder than the '*-ides' in the steel (but diamonds bring other problems to the table I won't get into here). AlOx and SiC work well because they are up to the job, but only just and on occasion, are not quite hard enough.
The chisel I used was solid HSS, and I think it's fairly obvious what happened when the King stone was tested with it. The steel was as hard/harder than the abrasive so the stone couldn't work. It actually felt greasy on the King stone because the stone would not cut the steel at a rate that allowed the stone to work effectively. If I'd used a microbevel, then I know the King would have worked to a degree but then I'd still be in the dark as to how effective King stones are with hard HSS.
A similar effect occurs with the Sigma ceramic #120, compared to any other very coarse stone out there. Most of these stones use the 'King method' of shedding grit quickly, offering fresh abrasive all the time in order to cut quickly. It doesn't work that well though, especially on very tough steels because the stone dishes so rapidly, you end up doing more harm than good. The Sigma uses a much stronger binder that allows the grit to hang around for long enough to start shredding the metal, not really abrade it. The Shapton Glass Stone #120 also has a strong binder, but for whatever reason doesn't have the guts on hard, tough steel. As a result, the Sig #120 chews through steel, any steel, like it's cheese and yet stays relatively flat. A unique stone, horrible to use but about as effective as using a sledgehammer to crack eggs.
Hone Rite Gold? I've already emailed Paul about it, and am trying to get a reply together for him. Unless the stuff contains something to significantly alter the surface tension of the water (like soap), then it won't make a lick of difference to the Shapton. The Shapton resin binder softens only when penetrated by water so soaking for 10 minutes or soap them up to speed up the time to soften them up a little and reduce the clogging. It won't stop it if the stones are pushed too hard. Fine grit ceramic stones do have a learning curve (compared to the dead easy to use King fine grit stones) but the small effort required to learn to use them is worth it. *
Hone Rite is interesting stuff, and I'm looking into it very much. Maybe not something I can sell because the store is "Tools from Japan" not "Tools in Japan" and I don't sell anything inside Japan at all, everything goes overseas. Any hint that something is not made in Japan, and I won't sell it. I'm trying to decide whether to relax that policy, or to try and find some other solution. I also need to find out what else is in there besides the anti corrosive stuff. Might be that something else needs adding to it, or it might already be in there.
This whole diatribe got a lot longer than I'd wished for, but I want to make sure that you guys out there are not looking at me as some blow in looking to shift some gear and make a bag of money selling some garbage, only to run away when you all wise up. I've used most stones out there, and have dozens of them of all kinds sitting here, most of them bought so they can be used just so I can be sure that when someone asks, I'm either already aware of how it works or it's a simple case of getting it out and using it. More than once before I've had to refresh my memory, and it's nice to be able to tell someone "Well, I just went and did what you have planned and..."
Stu.
*No, I don't use Shapton stones, except for analysis and testing purposes. Every time I use them I also have the equivalent Sigma ceramics out, and I'd have to have rocks in my head to believe the Shapton are better than the Sigma in any way. (Sorry, that looks like a sales pitch and I don't want to do that, but it's my honest opinion and to try and say anything different would be dishonest.)
