What's new

Importance of surface prep

How import is surface prep for getting the best out of your stones?

The importance of surface prep is well documented for Arks but what about other stones? I’ve welcomed a few new stones to the den recently. As part of the welcome party they all get lapped and get a slight rounding to any sharp edges.

I’ve noticed that a Thuris and Cotis can feel a little grainy under the blade for the first few sessions after an Atoma diamond plate. The stones then get smoother and smoother the more you use them. The Thuris get silky smooth to the point that water starts to pool on the surface similar to the way it would on a piece of glass.

Has anyone else noticed the effect that stones become smoother with use? Does this effect the final edge? There seems to be a balance between lapping enough and lapping too much.
 
I use inats and typically use a 1200 atoma to raise slurry. Ive tried lots of things and find that 600 grit finish on jnats anyway is more than enough. I use the 1200 as it penetrates the stone less and it's logical to think the slurry is composed of smaller particles. I used to use a bbw to finish the finishers. But didn't seem to gain anything.
 
How import is surface prep for getting the best out of your stones?

The importance of surface prep is well documented for Arks but what about other stones? I’ve welcomed a few new stones to the den recently. As part of the welcome party they all get lapped and get a slight rounding to any sharp edges.

I’ve noticed that a Thuris and Cotis can feel a little grainy under the blade for the first few sessions after an Atoma diamond plate. The stones then get smoother and smoother the more you use them. The Thuris get silky smooth to the point that water starts to pool on the surface similar to the way it would on a piece of glass.

Has anyone else noticed the effect that stones become smoother with use? Does this effect the final edge? There seems to be a balance between lapping enough and lapping too much.

I prefer to finish most finish stones at 1k or 2k w/d.
If you are a slurry user then this would be pointless.
After a stone is slurried it has a different feel to me, grabby, not so nice - this includes Thuries.
Synthetics get 400 or 1200 Atoma.
I think most finish stones, if used with just water, will benefit from a finer finish.
 
I will admit to a fear of the non-JNat natural stone. I have no Cotis, no Thuris, no anything that is neither a JNat, nor a synthetic. Ok, I have some little Dan's Arks that I bought secondhand and never used, but surely those do not count.

The other exception is the reason I don't have any of those stones. It's one of those Jasper stones from that excessively enthusiastic guy. I used the fine side to hone a razor, and got a saw blade that would be really good at cutting any spare arteries I might have laying around.

OK, surface prep. So I went through a very long and laborious sequence over many hours, culminating in burnishing with 8000 grit sandpaper. The surface was now shiny. So I put a razor on it, and got...pretty much the same sort of lethal saw edge.

Obviously there's something I'm missing, but until I have figured it out, I am steering clear of anything that needs "surface prep."
 
I do prep my Arkansas blacks and translucent's. Lap them up to 600 grit sic the 1K wet dry, sometimes I'll go 2K on them. After that just use them and they will break in a bit more. For a Coti I just lap with a worn 325 DMT and call it good, same for a Thuri. Seeing that they both use a slurry stone I don't see a need to do any more.

All stones get lapped flat
 
I do prep my Arkansas blacks and translucent's. Lap them up to 600 grit sic the 1K wet dry, sometimes I'll go 2K on them. After that just use them and they will break in a bit more. For a Coti I just lap with a worn 325 DMT and call it good, same for a Thuri. Seeing that they both use a slurry stone I don't see a need to do any more.

All stones get lapped flat
It’s this break in period after lapping that I’m talking about. I’m finding that all stones benifit from a little break in with steel after lapping.

I wonder if there is a benefit to wear them in a little with a chisel before razor use as I would do with an Ark.

I had a bit and miss experience with my Jnat. I used to raise slurry with an fairly new Atoma 1200. There was some correlation between very light pressure on the Atoma and a better edge. Some recommend using a well worn ‘mellow’ Atoma for raising slurry. Perhaps these broken in diamond plates leave a smoother surface prep on the stone.
 
It’s this break in period after lapping that I’m talking about. I’m finding that all stones benifit from a little break in with steel after lapping.

I wonder if there is a benefit to wear them in a little with a chisel before razor use as I would do with an Ark.

I had a bit and miss experience with my Jnat. I used to raise slurry with an fairly new Atoma 1200. There was some correlation between very light pressure on the Atoma and a better edge. Some recommend using a well worn ‘mellow’ Atoma for raising slurry. Perhaps these broken in diamond plates leave a smoother surface prep on the stone.

I don’t think a coti benefits from any break in like an ark does, nor does a thuri but I’m pretty limited in using a thuri.Not familiar with the Jnat
 
It’s this break in period after lapping that I’m talking about. I’m finding that all stones benifit from a little break in with steel after lapping.

I don't find this at all. After a nice 1-2k finish there is no break in period.
Arks are alone in this IMO.
 
  • Like
Reactions: Wid
I own many diamond plates; some are super worn/almost dead others are new and super aggressive. So that has to be recognized. I have a very very worn 400x plate, I use it to lap just about any stone and I hone on them right after and all is well. Polishing the stone further yields zero improvement of any kind. Sometimes it decreases the stone's ability to work well in a progression. If I am using a new diamond plate - I usually have to finish-lap with w/d afterwards. Most of the time there is no need to go higher than 600x. Once in a great while I'll go up to 1k with a super hard stone but I usually wind up bringing it back down to 600x later on.

Testing for the threshold of diminishing returns, or imagined returns, takes a lot of time, patience, rigid levels of consistency, and re-honing the same blade over and over again from 'zero'. Most people trying to prove a mirrored stone is best wind up re-finishing the same blade repeatedly; and after hitting 5-6 finishers with increasingly higher levels of polish they declare success based on a shave. Repeatedly re-finishing an edge is rehoning - not testing a finisher. Mostly, it's just making up for work that should have been done better the first time around. Or it's sort of a placebo effect, there's a lot of that going around on the internet. Without approaching this from the ground up using a system with controls and a really broad sample size to test with; anecdotal findings with limited scope can yield false positives and negatives.

I've had many, many, blades off scores of stones in every imaginable state of surface condition under my scope.
If the stones are flat and the work is on-point; excessive polishing past, say 600x, becomes more about taking pix for social media and pontification fodder than it is about anything else.

Woodworkers in Japan that compete yearly for who makes the sharpest Kanna and who can take the thinnest and longest shaving off a 10' hard-wood board keep their stones in a pail with 6-8 other stones of varying grit, slap one on a Dai, wipe the Kanna with a dirty rag, and work on it with a ton of swarf on the stone. While a Kanna is not a Kamisori, I can tell you that shaving with one one of them would be an eye-opening experience.

Flat enough, smooth enough, and without any visible issues, and you're probably good to go. 'Felt' distractions have to be removed, sure. Yah, the surface condition is important but fussing over it can be a waste of energy. But some people like shiny stones and if that's the case, then fine - everyone gets to do what they want to. No rules here. If what your doing yields results you want, whatever's clever rules the day.
 
I own many diamond plates; some are super worn/almost dead others are new and super aggressive. So that has to be recognized. I have a very very worn 400x plate, I use it to lap just about any stone and I hone on them right after and all is well. Polishing the stone further yields zero improvement of any kind. Sometimes it decreases the stone's ability to work well in a progression. If I am using a new diamond plate - I usually have to finish-lap with w/d afterwards. Most of the time there is no need to go higher than 600x. Once in a great while I'll go up to 1k with a super hard stone but I usually wind up bringing it back down to 600x later on.

Testing for the threshold of diminishing returns, or imagined returns, takes a lot of time, patience, rigid levels of consistency, and re-honing the same blade over and over again from 'zero'. Most people trying to prove a mirrored stone is best wind up re-finishing the same blade repeatedly; and after hitting 5-6 finishers with increasingly higher levels of polish they declare success based on a shave. Repeatedly re-finishing an edge is rehoning - not testing a finisher. Mostly, it's just making up for work that should have been done better the first time around. Or it's sort of a placebo effect, there's a lot of that going around on the internet. Without approaching this from the ground up using a system with controls and a really broad sample size to test with; anecdotal findings with limited scope can yield false positives and negatives.

I've had many, many, blades off scores of stones in every imaginable state of surface condition under my scope.
If the stones are flat and the work is on-point; excessive polishing past, say 600x, becomes more about taking pix for social media and pontification fodder than it is about anything else.

Woodworkers in Japan that compete yearly for who makes the sharpest Kanna and who can take the thinnest and longest shaving off a 10' hard-wood board keep their stones in a pail with 6-8 other stones of varying grit, slap one on a Dai, wipe the Kanna with a dirty rag, and work on it with a ton of swarf on the stone. While a Kanna is not a Kamisori, I can tell you that shaving with one one of them would be an eye-opening experience.

Flat enough, smooth enough, and without any visible issues, and you're probably good to go. 'Felt' distractions have to be removed, sure. Yah, the surface condition is important but fussing over it can be a waste of energy. But some people like shiny stones and if that's the case, then fine - everyone gets to do what they want to. No rules here. If what your doing yields results you want, whatever's clever rules the day.
I think 600 is a good spot for a finishing stone, in my case black/ trans arks, llyn idwal, slates I wouldn't consider same since the slurry stone is smoothing but anything part 600 or going through and burnishing feels like a waste to me. I like fine, aggressive stones. I like the feedback from them, and I like to see how sharp I can get the edge by doing lighter and lighter strokes and I feel like a super burnished edge isn't doing much with pressure even. I've got stone I sorely regret lapping and some I regret not lapping more. It's a really personal, and even then, delicate balancing act. I've turn my favorite stone into "don't know if I'll ever use that again" but they wander back eventually most of the time.
 
I think the grit rating of your lapping plate can be a bit misleading with respect to the condition of the surface it creates. A coarse 400/600 grit lapping plate might leave a better finish on your stone then say a 1200 if you use the same pressure. If i go higher then 600, the plate gets sucked to the stone, which increases the effective pressure on the surface.
I did a test once, where i dressed my hard coticule using different small vetrified diamond water stones. The finest plate (1200 FEPA grit/4000 JIS) created a glass like surface, but when i inspected the edge after honing on it, the edge was really torn up. After i did the same test using a course plate, the results were much better.
Are we talking about just surface prep, or are we also talking about lapping? Any surface prep i do is done after the lapping.

I have a few higher grit shapton gs seven HR. They seem cut a little different depending on how they are lapped and dressed. I dressed one of them with a 2k ceramic stone. This did not seem to improve anything. The best results i have gotten with these is to lap them with an atoma 400, and dress the surface with another coarser gs stone.
 
I did a test once, where i dressed my hard coticule using different small vetrified diamond water stones. The finest plate (1200 FEPA grit/4000 JIS) created a glass like surface, but when i inspected the edge after honing on it, the edge was really torn up. After i did the same test using a course plate, the results were much better.
There's a really good chance you left some diamond on the surface from the fine plate.
There is no way your edge should be torn up from a finer finish, it makes no sense.
Finer diamond plates are more likely to imbed than coarser ones.
The guy that used to sell Gokumyo's (Stan, I think) insisted on only using a 400 Atoma because the 1200 would imbed.
When you used your coarser diamond it removed the inclusion.

Try 220 w/d paper on the same coti and hone - inspect then try 1k on the same coti and inspect.
There will be a huge difference in the edge created.
 
Last edited:
There's a really good chance you left some diamond on the surface from the fine plate.
There is no way your edge should be torn up from a finer finish, it makes no sense.
Finer diamond plates are more likely to imbed than coarser ones.
The guy that used to sell Gokumyo's (Stan, I think) insisted on only using a 400 Atoma because the 1200 would imbed.
When you used your coarser diamond it removed the inclusion.

Try 220 w/d paper on the same coti and hone - inspect then try 1k on the same coti and inspect.
There will be a huge difference in the edge created.
I understand that there is a bigger chance to get imbedded diamonds. My point is that the force per area increases with finer diamonds. So with the same pressure a finer grit can do more damage to the surface. I know that softer synthetic stones are prone to get imbedded grit, but the coticule i tested is really hard. The stone did not perform well. When you brake in a coarse diamond plate the peaks shear off. This enables the coarse diamonds to actually create a finer surface. Shapton has an instruction manual were this is explained. They recommend braking in their coarse plate to shear of some of the peaks. I think the plate is around 320 grit. This is not something i came up with.
Finer diamond plates can also have clusters of diamonds that create more damage.
 
I understand that there is a bigger chance to get imbedded diamonds. My point is that the force per area increases with finer diamonds. So with the same pressure a finer grit can do more damage to the surface. I know that softer synthetic stones are prone to get imbedded grit, but the coticule i tested is really hard. The stone did not perform well. When you brake in a coarse diamond plate the peaks shear off. This enables the coarse diamonds to actually create a finer surface. Shapton has an instruction manual were this is explained. They recommend braking in their coarse plate to shear of some of the peaks. I think the plate is around 320 grit. This is not something i came up with.
Finer diamond plates can also have clusters of diamonds that create more damage.

Hard stones are just if not more prone to it.
You are talking about the diamonds ability within its wear schedule, not the finish.
The OP is about surface finish whether its from a very worn coarse diamond or fine diamond/w/d.
This was my point.
Its the finer finish that gave a better result.
If the finer diamond plate was worn in then it would also not cause problems and leave an even finer finish.
 
Are we talking about just surface prep, or are we also talking about lapping? Any surface prep i do is done after the lapping.
Interesting stuff. My original question is about the importance of dressing the surface after lapping. Is it required and does it make a difference?

I’m finding that the surface feels smoother under the blade if a stone has been dressed with another stone after lapping or had some hard steel run over it for a while.

It could be in my head. It might also be more important with harder or softer stones. It seems to make sense that eventually any roughness left by the lapping plate would be smoothed out with use. The effect on the edge may be marginal but the feel while honing can be quite distinct.
 
Interesting stuff. My original question is about the importance of dressing the surface after lapping. Is it required and does it make a difference?

I’m finding that the surface feels smoother under the blade if a stone has been dressed with another stone after lapping or had some hard steel run over it for a while.

It could be in my head. It might also be more important with harder or softer stones. It seems to make sense that eventually any roughness left by the lapping plate would be smoothed out with use. The effect on the edge may be marginal but the feel while honing can be quite distinct.

Most stones will smooth out fairly quickly but as a finish quality, even with softer stones, the immediate affect on the edge is noticeable.
With an Escher dressed coarser vs fine, immediately after dressing, the fine will leave a better edge.
I have experimented long ago with all the stones I had at the time and it was universal when using water alone immediately after dressing.
Microscope does not lie.
 
Interesting stuff. My original question is about the importance of dressing the surface after lapping. Is it required and does it make a difference?

I’m finding that the surface feels smoother under the blade if a stone has been dressed with another stone after lapping or had some hard steel run over it for a while.

It could be in my head. It might also be more important with harder or softer stones. It seems to make sense that eventually any roughness left by the lapping plate would be smoothed out with use. The effect on the edge may be marginal but the feel while honing can be quite distinct.
That's residential what people call burnishing. I buff newly lapped stones with other stones or worn out diamond plates to smooth them out but I don't rub them down with tool steel unless it's what I'm honing on the stone.
 
Top Bottom