Turned my Spyderco bench stone into a combo-stone! (write up / pic's)

Cereal_killer

Cereal_killer

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Apr 4, 2013
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Last week I read a post and then started doing research on how some people were lapping their ceramis stones [SM rods] to effectively make them higher grit. The material is the exact same between fine and ultra fine (confirmed by Sal) the only difference is the surface finish. Being cheap it got me thinking, do I really need to buy another $50 stone? Can't I just make my one fine ceramic stone into a combo-stone?

Well yes, I could!

I had planned on this taking all weekend working a few hours a day but I found it actually wasn't as hard on my hands as I had thought and I was able to accomplish the task in just two days. I started out buying a set of lapping plates from harbor freight and flattening them with careful attention to detail, a punch and rubber mallet on a piece of wood (these arnt as wavy as some of those 4-sided Harbor Freight diamond sharpeners but still needed work). The plates were 180, 220 & 360 grit. I also used my fine (600) and EF (1200) DMT plates.

First I started off by flattening both sides of the stone with the 180 plate, draw a grid so you can tell when its flat.
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I got setup with a perfectly flat block of wood as my base, a 5-gal bucket of soapy water and a comfy position to sit down over the work.

Do both sides like this till your satisfied they're flat. You'll want to dunk both the stone and the plate in the bucket pretty often and don't use much pressure.
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That's that, stone is flattened, note this part took me a day by its self.

Next up pick a side to be the extra fine side and mark it, once your done its simple to tell but you don't want to mix it up while your working. Now that it's finished I can easily tell the difference just by feel, even my wife can tell which one is which in a blind test.

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Now we start in again, draw a grid to make sure your staying flat and to monitor progress, I spent about 90 minutes with each of the 220, 360 & 600 plates (redraw grid when needed).

After that I moved on to the EF (1200) DMT, this final one took about 2.5 hours of work to get to a point I was happy with it. Same process.

The final outcome is amazing, these are not very good pic's but hopefully they will show enough.

This is my Sebenza off the "fine" side (at >2500 this is already very refined and very sharp, I was able to get the light just right to really show the scratch pattern) notice the burr.
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And the after the "ultra fine" side (here there is almost no visible scratch pattern to the eye, only under HCRI light held at a low angle was I able to even get this pic)
AEB17D79-3480-42E3-AE9E-CE5ACA08CF3F.jpg
 
Congrats on having that much patience. It looked like it turned out really well. How did you get the plastic of the back of the HF plates?
 
jobasha11 said:
Great job:thumbup: What would you estimate the extra fine to be grit-wise now?
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I'm not able to give a good estimate, I'd put it somewhere around 10k but I'm not sure. I plan to do some experimenting here soon to try and figure out a smaller guess. Also the "fine" side went up in grit after lapping, I'd say its pretty close to 3-4k.

fervens said:
Congrats on having that much patience. It looked like it turned out really well. How did you get the plastic of the back of the HF plates?
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I got lucky, the glue didn't hold, opened the package (bought them just for this) and they were all apart.

Thanks guys.
 
Can you compare the speed of the fine and extra fine stone to before?

And damn, looks like mine were better quality. that sucks :P
 
fervens said:
Can you compare the speed of the fine and extra fine stone to before?
I can't offer much insight on that, I'd say they take more time but I'm not sure, I only have this one data point since doing it so just not enough info to tell
And damn, looks like mine were better quality. that sucks :P
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Yea but I got lucky, like I said I bought them specifically for this use (didn't want to risk my C/XC DMT), I would never use them on a knife blade, to inconsistent of a surface. After I was done I returned them and didn't feel like I was deceiving them since technically they were broken when I took them out of the package.
 
Four years ago while on a road trip, I used a HF four sided diamond sharpener that a friend had, to sharpen his kitchen knives. It did a surprisingly decent job, and he said it had cost very little money. That was the last time I took a road trip without my own sharpening gear.
 
"to effectively make them a higher grit." CK
You did a good job taking much more time and expense than I did. Looks good, I hope it was worth it.
One cannot change the grit of a stone it will always be the same. However, changing it's surface and leveling it then helps it produce a finer edge. Plus, I think this change lasts a long time. Especially, for that stone. DM
 
David Martin said:
One cannot change the grit of a stone it will always be the same. However, changing it's surface and leveling it then helps it produce a finer edge.
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The material is exactly the same, the abrasive size and the distribution in the matrix is the same, this has all been confirmed by Sal. The only difference between the two unaltered stones is the surface finish put on them by the factory. Did I not accomplish the same thing the factory does effectively changing the grit size?

The ceramic particles are so hard I didn't abrade them away, the diamonds sharpened each individual particle making them smaller/finer.
 
I know what Sal said as I was a member and read it when he posted it. Yes, you did the same thing as the factory. Still, the grit size is the same...
They are merely resurfacing the stone. Giving it a finer 'feel'. Not making the grit smaller. In order to make a stones grit finer one would have to start with finer grit. DM
 
David Martin said:
I know what Sal said as I was a member and read it when he posted it. Yes, you did the same thing as the factory. Still, the grit size is the same...
They are merely resurfacing the stone. Giving it a finer 'feel'. Not making the grit smaller. In order to make a stones grit finer one would have to start with finer grit. DM
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I'd love to get some micrographs with lighting at a shallow angle to bring out the surface detail. I get the feeling the Fine/Extra Fine Spyderco stones behave more like a file than a stone. I imagine if one were to flatten one and then surface finish with diamond making the scratches all in one axis you could get some very interesting effects.

I lapped mine with SiC, and while it is far smoother than the opposite side - as a ceramic it has been worked too smooth and is only good for surface deformation of the steel - burnishing. I keep meaning to resurface it with a fine diamond stone but just don't have the desire.
 
I lapped my spyderco fine stone with one of my old cheap diamond sharpeners, 600 mesh. Turned out quite well.
 
http://moleculepolishing.wordpress.com/2013/08/08/the-mystery-of-the-spyderco-and-the-wicked-edge-ceramic-stones/

disclaimer: more theory than anything.

I really don't think saying these stone have a specific grit is a good idea. They are sintered together meaning there is no binder. It's now one large chuck of AlOx. It looks like it acts more like a mix between a cheese grater and a file. Especially after lapping it. Coarser stones leave larger "teeth" (think teeth on a file). The finer the finish though, the more it acts like a cheese grater where the valleys in the stone are level with the surface finish.
 
This is interesting that two gents relate this stone to a file. I didn't think of it in that manner. DM
 
Ok, this afternoon I had more time to read and ponder fervens posted link. Which I thought was very interesting. Thanks for giving it. So, lapping my Spyderco ceramic stone and finishing at a fine diamond level left this level of grit embedded in the stone. Making it no finer than 600 grit. At least leaving much of this grit on the ceramic stones surface. Then Cereal's would be at 1200 grit.
The conclusion would be that one would have to lap the ceramic stone up to EEF (3 micron) to bring it up to that level. Then one still has the problem of very large AlOx grit on the stones surface to guess about it's influence on the knife's edge. ?? DM
 
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This causes one to wonder what grit did Spyderco finish their Ultra Fine stone with.? As that's what is left on it and the scratch pattern with express this. DM
 
David Martin said:
Ok, this afternoon I had more time to read and ponder fervens posted link. Which I thought was very interesting. Thanks for giving it. So, lapping my Spyderco ceramic stone and finishing at a fine diamond level left this level of grit embedded in the stone. Making it no finer than 600 grit. At least leaving much of this grit on the ceramic stones surface. Then Cereal's would be at 1200 grit.
The conclusion would be that one would have to lap the ceramic stone up to EEF (3 micron) to bring it up to that level. Then one still has the problem of very large AlOx grit on the stones surface to guess about it's influence on the knife's edge. ?? DM
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I've come to believe it's not so straightforward, in assuming the effective finish on the ceramic will be the same as whatever diamond grit was used to lap it. I used either or both of DMT's Coarse (325 mesh/45 micron) and Fine (600 mesh/25 micron) to lap 3 ceramic hones of mine (or 4, if counting both sides of a Spyderco DoubleStuff hone). All of them finished at a level way, way finer than either of those grit specs (well beyond Spyderco's 'Fine'). Have to account for the fact that even if using a 45-micron diamond grit, it's not likely to cut anywhere near as deep as it would in much softer steel, and therefore won't leave as 'coarse' a scratch pattern on the surface. I think this is why it's often been recommend here and in other forums, that if attempting to match Spyderco's existing finishes, one needs to start with a diamond grit much, much coarser. Often see a recommendation to use XC/XXC diamond hones, in order to get somewhat close.


David
 
Agreed, at least some what. It's hard to argue with the microscope as the scratches are present. Yes, I've thought my ceramic stone, the side I finished expressed a finer edge. Still, I couldn't see the scratches without higher magnification. So, at least parts of both affects are present on the edge (smoother & scratches). Now, what can we say about these huge AlOx grains left on the surface of the stone with there tops sanded down? When the diamonds are gone they will remain for a long time. The correct observations from the two astute members above (fervens & Heavy) comparing it to a file and cheese grader. Is accurate. I would liken the stone to a rasping file or a horse shoeing file. Only this isn't quite accurate in 2 accounts either. One, these are very coarse and the pattern not random but uniform. Still, I can see the similarities. There is room on this subject for differing observations but the photos are compelling. DM
 
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