Recommendation? Condition Ceramic stone

I'm surprised there was no glazing, taking the dressing that fine. This shows the stone was off level even after being factory ground to ultra
fine. It does take a lot of elbow grease. Good job. This stone is capable of a very fine finish. DM
 
David Martin said:
I'm surprised there was no glazing, taking the dressing that fine. This shows the stone was off level even after being factory ground to ultra
fine. It does take a lot of elbow grease. Good job. This stone is capable of a very fine finish. DM
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Not exactly. The stone was probably level, but there are machining marks in the surface, meaning that while it is flat, it is not completely smooth. The hardness of the bond causes these micro-ridges to function somewhat like the teeth of a file, and this is the chief reason why the degree of edge refinement produced increased. Secondly, glazing can mean two things, neither of which is especially tied to this kind of surface treatment. Namely, it can mean either clogging (buildup of swarf that embeds itself in the stone), which is almost always the result of dry honing, or it can mean the abrasive grains dulling, which produces a shiny, slick surface that burnishes rather than bites.
 
When I look at the link that ckdex gave and bastl's efforts at working this stone... He shows a photo of a grid he drew on the stone, then started grinding. Where the grid was first removed is a classic sign of a stone being out of level. DM
 
FortyTwoBlades said:
Not exactly. The stone was probably level, but there are machining marks in the surface, meaning that while it is flat, it is not completely smooth.
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He describes that the stone was not level and it took him two hours with the DMT 120 until it was level.

Here you can see that in the beginning only some part of the stone was removed due to it no being level:

30301182hq.jpg


And even this was probably after having worked quite some time on it. I am doing the other side now and have lapped quite some time and it is still not level.
 
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Yep, (that's it) it cuts real slow. Thank you for these photos and your efforts in making it level. DM
 
ckdexterhaven said:
He describes that the stone was not level and it took him two hours with the DMT 120 until it was level.

Here you can see that in the beginning only some part of the stone was removed due to it no being level:

30301182hq.jpg


And even this was probably after having worked quite some time on it. I am doing the other side now and have lapped quite some time and it is still not level.
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If it was that far off level it would have been better to get it replaced under warranty. Those are supposed to be dead flat from the manufacturer.
 
Seems like something Spyderco needs to address with their manufacturer. What are they paying for if they're not flat?
 
Something like this is what I'd consider an acceptable degree off of dead flat for a sintered ceramic. You might want to flatten it for razors, but for anything else, that's more than close enough.

52679028_10217905982229635_6223357863297810432_n.jpg
 
Several of us are finding them way more off level than that. The factory has had one or two tries to get it level. How come we can do a better job w/ simple tools?
1) the main benefit is we are able to get a flat stone.
2) a side benefit is we get a finer surfaced feeling stone which imparts this to the edge. DM
 
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I think a major part of it is that the machine hours of grinding is pretty severe. It's expensive and time-consuming to grind sintered ceramics. Like...REALLY expensive. You end up burning through a lot of costly diamond abrasives doing that work and it's not at all rapid. The amount of time it takes to flatten a not-too-awfully-uneven sintered stone by hand isn't a huge investment for an individual, but imagine if you were making hundreds of them and what you'd have to charge for it and account for in your pricing structure. It would balloon the price massively. But that being said, it's really weird that folks are getting stones that aren't pretty dang close to flat since that's what they're being paid to to them.
 
FortyTwoBlades said:
I think a major part of it is that the machine hours of grinding is pretty severe. It's expensive and time-consuming to grind sintered ceramics. Like...REALLY expensive. You end up burning through a lot of costly diamond abrasives doing that work and it's not at all rapid. The amount of time it takes to flatten a not-too-awfully-uneven sintered stone by hand isn't a huge investment for an individual, but imagine if you were making hundreds of them and what you'd have to charge for it and account for in your pricing structure. It would balloon the price massively. But that being said, it's really weird that folks are getting stones that aren't pretty dang close to flat since that's what they're being paid to to them.
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I wonder how many people figure it out—right away.

A novice sharpener may figure it's either his technique or the blade may be ground or sharpened imperfectly, or just accept or it —not knowing any better—or not even notice or realize the ramifications.
 
In a lot of cases, people simply get used to a concave stone and still manage to produce edges that get the job done. If you look at old stones in antique shops you can clearly see incredible amounts of wear on most of them, without them seemingly ever being flattened. Presumably these individuals did still see a big increase in edge performance after sharpening or else they probably wouldn't have used the stones so heavily! It's not ideal, certainly, but apparently they still got the job done!
 
Yes, and I was thinking about expectations for a pricier new "stone."
 
I'm saying people who don't realize the stone has a slight warp probably just get used to it and still get their blades sharp enough. In cases where it's REALLY out of true then it probably becomes pretty obvious.
 
Speaking from the perspective of a machinist, it's not easy to grind something this thin with this much surface area perfectly flat. Even the act of clamping it in a vise or fixture can distort the thing a tiny bit, then you grind it flat but when it's released from the holding fixture or vise it springs back from that distorted state. My own Spyderco 3" x 8" UF was a little out of flat but for knives it was fine. Since I planned to use it for razors I flattened and resurfaced it on one side. One side I use for razors, one side for knives. Here is a decent image comparison of the difference between the two sides as far as texture:

Factory finished side:

20180909_224307.jpg


Flattened and refinished side:

20180909_224329.jpg


Note that the grooves visible in the factory side from the diamond grinding wheel can barely be felt with a finger.
 
Yeah me neither now, I don't know why. They were working fine earlier. More photobucket B.S. Right click them and select "Open in New Tab" and they'll come up in photobucket.
 
Time to report back. I just finished sharpening a hunter in ~62-63HRC 52100. Progression was:

Apex (form burr) both sides with Naniwa Pro 400. Deburr on this stone
Refine Shapton Pro 1000
Refine/polish Spyderco Fine (60/120 grit SiC conditioned)
Edge angle was constant and extremely accurate 13 degrees per side (guided).

All I can say is wow. I am extremely impressed with the new edge of the conditioned stone! It has quite a bit of bite to it, but is very much polished...what I would say almost mirror. Mirror is hard for me to tell because my edge bevels are tiny (I grind thin.... as in 0.005” prior to sharpening).

The feedback was noticeable. Instead of my usual “feels like a glass plate”, the newly conditioned stone actually “cut”. I could actually feel this thing cutting! Almost like a 1200 mesh diamond plate. It was smooth, but I could feel the stone ever-so-slightly digging in to the steel.

I’m sold on the process. While the cheapo fine diamond plate did seem to help initially, the loose 60, and then 120, SiC powder transformed this stone into something I really really enjoyed. Obviously one might could get the same results lapping with an XXC diamond plate, or Crystolon stone, I didn’t want to risk the damage to my DMT/Atoma plates or my Crystolon stone.

I highly recommend the loose SiC powder for Spyderco stone conditioning. If and when the time comes again, that will be my method.

The edge is simply stunning. It was lengthwise splitting arm hair still on the arm, but felt very very aggressive with the fingertip feel of the apex.

Thanks for all the help and info. One happy Spyderco ceramic stone owner here.
 
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