A bit of sharpening sacrilege to brighten your day.

[truckjohn]

On the loose diamonds on the plate... Try it out and tell us how it goes. It is cheap enough to experiment with. A 5-gram tube of greased diamond paste runs ~$10 from a lapidary supply. I think you could certainly gain some cutting power from the loose diamond product, at least until you cleaned it all back off. The challenge is getting stuff like this to stay put. Start a lapping session with dry, loose abrasive, and soon, it's all over the place.

The tumbling media behaved like it was simply not tightly graded. While I have no doubt the majority of the abrasive was 3 microns and below, there was a lot of stuff that scratched like 20-30 microns. I'm going to try again with some more tightly graded aluminum oxide "Polish" products. It's still pretty cheap compared to a stone.

I think one of the challenges with the really fine stuff is just getting it to lay down. Stuff down under 1-micron could take 12-24 hours to settle out of an oil. I would guess a teeny pinch of the stuff would just keep floating around in oil forever, and the tool
moving across the stone would just "stir" it. The trouble then becomes that the only thing that lays down on the stone surface is the coarsest stray abrasive and any grit that pulls out of the stone. I even had that with the Shapton. A dozen or so sessions later and the finish was getting scratchier till I washed it off real good. The lapidary guys slop their fine polishes pretty thick and pasty, which sort of makes sense. That may also be one of the reasons abrasive on wood works so well - the wood sticks it down so it doesn't just float away.

[D.W.]

sure, but I don't know if they do any better than they would on any other piece of mild steel. Or better yet, good quality blanchard ground cast.

however, I remember bill tindall mentioning this and I agree - cast and mild steel with embedded diamonds is an errand for fine diamond. A diamond hone is better for work prior to a microbevel because if both the final and prior step have loose diamond, coarse diamond will end up in the cast plate and spoil the effort (and it will, significantly).

I think if you're flattening something new, good quality aluminum oxide paper with adhesive backing so that it can't lift and dub things is still going to be faster other than in cases of steels like 10V where aluminum oxide will cut the steel but not the carbides. Even then, it may still be faster just smashing the carbides and breaking them out as it cuts the rest.

My vote for day to day if you have a tired plate is buying one of the inexpensive import plates off of aliexpress - should be about $20US for one that's 8x3 with two sides.

For the fine end of things, the loose diamonds are great.

For a case where you're just doing a one off preparation and you won't bring coarse loose diamonds to something else by accident, then loose on an old plate is fine - but maybe not as good as just plain steel because the nickel plate may keep the diamonds rolling around on the hone where you're really better off if they embed in the softer surface so that they cut the harder one (the tool).

mild steel is OK for this, cast is better for reasons I don't know - it just works a little better, but it really needs to be flat and it needs to be free of defects of big scratches, especially for fine work. surface grinding and other striations will actually hone and edge (not the right way) and leave a burr.

[truckjohn]

So I've been trying out various grits of Alumina on several soft Arkansas stones now, and I really like it. With the abrasive powder, it doesn't seem to matter whether you use water base or oil base honing solutions. Both work well. I think maybe oil has a slight edge on feel and speed at the more coarse levels. I think water base has a slight edge when going to the finer grits as it tends to lock up the Ark's grain structure. It produces a finish more consistent with the stated abrasive grit.

The main key thing you want in the stone is simply no tendency to throw sandy grit. Stones that throw grit are always a problem, but it kinda ruins your day when running 1 or 2 micron abrasive.

Another thing is that so far, soft Arks work better as substrates than hard ones. A medium density soft with a fairly even texture has an amazing feel with the abrasive. A translucent Ark, on the other hand is horrible. Perhaps it just means I need to try finer grit, but even 1-micron abrasive on a translucent is a train wreck, with the stone alternating between ultra-grabby/chattery and greased glass with zero feedback.

An interesting observation is how glassy and smooth the arkansas stone surfaces get. Especially with water and finer grit abrasives. This doesn't seem to hurt anything like it does when honing without any abrasive powder, as the abrasive does all the cutting while the stone simply acts as a substrate. Water base might actually be beneficial, as it glazes/deadens the inherent structure of the stone. This probably needs a bit more experimenting, but there's something here.

Another interesting thing is how fast it goes. I can go straight from a fine India to a soft Ark doped with 1-3 micron graded alumina, and it works through the scratch marks and leaves a pretty darned shiny finish. 1,200 tumbling grit on a super low density, cheap soft Ark wipes off scratches from the india stone like they aren't even there, and then sets up the super fine alumina on a different stone to polish.

It's got me thinking about trying this out on some A2 and maybe even M2, just to see, but I have a feeling that the alumina will cut it, as you can sharpen both of these on sandpaper.

[D.W.]

M2 has some vanadium carbides in it. Silicon carbide will probably partially cut it, but aluminum oxide will not. If efficiency is important along with fineness combined, diamonds are necessary.

I can't remember what a hard ark is like with micron diamonds on it, because I just don't want those stones to have micron diamonds in them. they are a polishing stone, and really should just be used to their advantage. If you have a denser washita or a "hard arkansas" and use decently hard steel, you'll get a result that looks like this, and without the grippy nonsense.

https://i.imgur.com/IC0FN1p.jpg

This is the edge from a dan's black:
https://i.imgur.com/JhQUlZ1.jpg

I guess the finer stones excel perhaps when something is really small, like a graver or dental tool or a carving gouge. But for chisels and plane irons, I saw no functional difference in edge life or fineness over a settled in washita when doing a planing test in , I believe, 2018 or 2019. In fact, functional is understated - in carbon steel, I saw no edge life difference at all compared to a standard of 1 micron diamonds. Both lasted in a clean wood test 85% or so of the footage planed by the 1 micron diamonds.

This is the same washita stone with heavy pressure instead of light:
https://i.imgur.com/ar1veAw.jpg

The difference is a little overstated in pictures because of something that happens based on polish. The closer a surface is to polish, the brighter the light back into the metallurgical scope vs. scattering more all different directions in great amounts. But there's a pretty big difference.

The amount of time to get from this coarse finish to the fine one above is probably about 15 seconds and judicious use of pressure. light pressure finishing leaves far fewer defects in an apex, too. Yet another reason to finish only the tip of the tool, to make sure that it is worked with no deflecting pressure that may occur freehanding before final finish.

The washita is a better fit for 2 or 3 micron diamonds if you need speed, but a bonding grade mix of 1-3 microns works great on the ruby stone you have. why on the fit? it will still cut fast enough in a lot of cases to sort of overpower 1 micron diamonds, which are fast for 1 micron, but the reality is no really fine media is very fast and the finer it gets the more targeted it needs to be just to the edge of a tool. Ultimately, nobody will sharpen in the long term without at least a pressure bias toward the tip, which is what I actually see on japanese tools that I bring in, too. They never actually have a laser flat bevel. That's make believe for people who write 7 minute sharpening procedures for magazine articles and beginning students.

[truckjohn]

So... More experiments. The porosity of a soft Arkansas stone seems to be important to its behavior as a substrate. I tried some 0.5 micron Alumina polish called Raybrite A, and wow. This particular polish mixes into oil better than water. On a quality, very even textured soft Ark that does not throw grit, it leaves a that's better than anything else I have besides buffing. I would say it's at least on par with the finish I get stropping, but I can wash it right off the stone if I get crud on it. (Grit contamination is a real problem with my strop.)

I tried the same stuff on a translucent. While it's the best of the abrasives I've tried on a translucent, it's not "Good," in either feel or finish. That's basically a dead end so far as I'm concerned, especially when compared against a good soft ark doped with the same stuff.

On the stone itself... The one thing I need out of a soft Arkansas to be a good substrate seems to be simply zero tendency to throw grit. Uniform porosity appears to be beneficial, but not a deal breaker to performance. To this end, expensive, high quality soft Arks work several orders of magnitude better than low quality ones. The cheap ones I own show a definite tendency to throw sand, as well as a structure that's got hard lumps mixed into the softer matrix. Neither of those qualities are beneficial, either as a stone, or as a substrate, which is probably why they're so cheap.

One more important thing that sounds obvious when I say it out loud is... I gotta work harder to maintain a clean work area and develop better practices to avoid grit cross contamination. These stones are hard. Stray grit leaves big scratches on the tools. 500 grit silicon carbide looks pretty fine until it leaves a gouge.

BAE5855E-35FA-4055-8DCB-E72119A3CDD6.jpg

[D.W.]

I think you'll find that loose finish grit is the only you'll tolerate unless you come across an IM 313. You can put silicon carbide grit on a fine india in an IM313 and then eliminate it pretty easily when wiping off the oil.

Other than that, i found the finish step is the place for the loose grit. Of course, anything is fine going into the buffer, so if you have the ruby chinese stone and step it up with diamond flour, the buffer will just fling out or not really use anything that goes into it that isn't a majority of the polish.

Weaker cutting soft arks and middle ark stones definitely make a better base for this - beyond the loose grit, if you have a very strong cutting washita that doesn't ever really fully stop, it can cancel out the effect of a 1 micron loose grit by still just cutting faster than the loose particles.

Stones are a funny thing - everyone wants imaginarily fast and fine - and in the natural japanese market, the claims are just stupid and the desires are dumb. A step off of fineness fast stone is (or should be) inexpensive and can be paired with a really fine but slow finisher and still be faster than a stone that's sold as imaginarily good at both. I imported a bunch of used japanese stones years ago, graded them and sold them on etsy. It was hard to get it into peoples' heads that I wasn't selling them junk by telling them a better way to do things than searching for a $600 perfect stone.

Two different times, I had people who were spending thousands of dollars on stones (probably on credit) come back and say, I got 6 stones from ______ to try out, all are $500 or more and none are better than the stones you sold for $75-$150.

In my opinion, a fast finish stone with no control is a curse. it's based on the fallacy that there is a big flat bevel and you want to cut everything off of a bevel in a layer without understanding using a slower and as fine or finer stone to address just the apex of a tool on the final or penultimate step, and you need some nuance to do it. Stones that have that nuance cost almost nothing.

Overpriced stones that probably have a fake stamp (natural) or come from harrelson stanley (synthetic) are just nonsense.

[truckjohn]

Yep. I could totally see that with the stones. There's a lot of mythology out there, and a lot of magical thinking. I get that when testing gear, you'll eventually pick something as "The best." That's simply the mathematical definition of "Average."

I'm happy with the fine India with a shake of 500 grit silicon carbide. It's fast but doesn't leave huge scratches on anything. So I have $30 in the India stone that wanted to glaze over too quickly which is fixed with a pinch of $15/pound of loose abrasive.

Same for the cheap soft Ark that glazes too fast. I paid ~$50 to learn it was a poor stone. A pinch of $15/lb abrasive fixed that. Sure, in hindsight, Shapton or Naniwa water stones would have been a better place to start, but that would have been another $200 vs the $60 I spent on loose abrasive.

The thing is, everything in life is a compromise. Yeah, with loose grit, you have to fool with one more thing, but it's cheap and fast and you can calibrate the level of aggressiveness you want. On the plus side, there's no pond. You can use water or oil, whatever floats your boat, and if you want to switch, just scrub it off with dish soap and hot water, and off you go. So far, there's hasn't been a need for additional flattening like with quality water stones. I'm sure at some point there will be, but that goes pretty fast with sandpaper rather than a $300 diamond plate.

[D.W.]

I've had gobs of synthetic stones, and would never give up a set of arkansas stones with loose abrasive to go with it for any of them. That includes naniwa's best and shapton's best.

Really includes anything synthetic waterstone, period.

[D.W.]

They're not really going to get what you're doing on SMC. Sometimes you want the arks to cut faster without having to go to another type of stone - at least not below a fine india.

There is a capability and feel to ark stones that others don't have. They will let the grit embed enough to make it useful, and other things (spydercos, jaspers, etc) won't.

Warren brought a chisel the last time he was here - he knows how to sharpen things so that they don't get damage in use - but he's not going to see using stones any way other than what he does. He means well, though, and he does have a lot of legitimate experience.