I think I am going to flatten my Spyderco ceramics.

S

Squashfan

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Jun 6, 2012
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Long time no see, fellas! I am still an active knife nut but the hobby has been going different directions. I am starting to get into wood carving and general wood working. As with anything, sharp tools are the first must and I thought that the Spyderco ceramics that I have laid in would be great. Just one problem. I know my medium stone isn't flat and I think that my fine stone isn't flat either. I just did a search an I have seen where Spyderco would probably replace them. Except that I partially flattened one side of the medium and most likely voided the warranty. But I need them flat and square to work for the precision tools that I will be sharpening. I don't want to take a chance on blind returning them to the factory. So I am going to order some of the cheap lapping plates Cereal Killer used to flatten his stone. I am slightly concerned about making the stones finer but that is a chance I will have to take. We will see what happens!
 
This has been discussed here a lot, so, there is much info.. I did mine with a coarse diamond... Don't do it with this. YOu can try those flattening plates. Ceramic is very hard so it can glaze. Go slow and check it. Good luck. Once you have it done it stays that way for a long time. DM
 
Am having a little trouble with quoting your post. Why do you not recommend lapping with a coarse plate? And wouldn't working in water prevent some of the glazing? Seems like I will have to do a more in depth search tomorrow. Thanks for the help!
 
If you are going to do this my recommendation would be to use loose grit silicon carbide for the lapping. Lapping with diamond will result in a worn out diamond plate PDQ. Using loose grit also gets you a more "open" surface that will cut better and give the swarf somewhere to go. I wouldn't go above 600 grit loose SiC for the UF if you want it to still cut with any decent speed. For the F maybe 320 grit and the M probably 120 will be sufficient.
 
eKretz said:
If you are going to do this my recommendation would be to use loose grit silicon carbide for the lapping. Lapping with diamond will result in a worn out diamond plate PDQ. Using loose grit also gets you a more "open" surface that will cut better and give the swarf somewhere to go. I wouldn't go above 600 grit loose SiC for the UF if you want it to still cut with any decent speed. For the F maybe 320 grit and the M probably 120 will be sufficient.
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I didn't find the thread when I searched but I have seen that before. The only place I know of to get loose SiC grit is from a rock tumbler's supply. I think it is called lapidary grit. Would lapidary grit work in the numbers you gave? Thanks!
 
Flatting the ceramic will eat up a diamond stone as they are very thin. Try searching a topic we discussed recently which will cover this was, 'leveling a new SiC stone'. There was a gent who posted where to get the grits and all. Yes, water helps. I stopped at the fine diamond (600 grit). It will tend to glaze if you go finer.
Another member did this project last year and posted much about it. He used diamond stones and took his to 1200 grit, extra fine. I still would go the SiC route. As it's more economical. And the last grit used will remain embedded in the stone for sometime. Good luck, DM
 
I would send them back first and try that route. The loose SiC can be used to flatten the ceramics but will also have a negative effect on the grinding characteristics. Maybe you could flatten them with 80grit SiC and finish off with a coarse diamond to carve some surface effects back into the stone.
I flattened my Fine using SiC and while it did flatten it, it is useless for anything but burnishing now. Someday I'll go back and surface it with diamond, maybe restore it to good use.

Even if the stone is not flat, as long as you use the entire surface and don't hit the same spot on the stone every pass on the same spot on the tool, you should be fine. Move it around - if it hits a slightly high spot one pass, slightly low spot another, flat spot on a third - you will never know the difference.
 
There is a lot of misinformation on this subject. It won't hurt any steel removal characteristics if you don't go too fine. In point of fact it will improve them. Lapping with a diamond plate deadens a stone FAR more. If you think a diamond plate is any different try lapping a stone with a 1200 grit diamond plate - the stone will be slower than molasses.

An important thing to remember when using SiC grit to lap is that it breaks down finer and finer during use. This means that just because you start with 80 grit and lap for 5 minutes doesn't mean you have an 80 grit finish! If you want an 80 grit finish you need to charge the lapping plate (add grit and lightly soapy water - few drops of soap in a water bottle) and start lapping, then charge it again, lap lighter, charge it again, lap lighter for maybe 5 or 10 figure eights each time until you have an even finish. Then you'll have an 80 grit finish. (Or substitute whatever grit you're using/wanting).

I have done this (SiC lapping) many many times on many different types of stone, from Shaptons to Spyderco ceramics to Arkansas stones to slate stones to you name it. The grit will not embed on any but the softest stones either. A key component in this is to do your final lapping with very light pressure. This allows the grit to roll over and scrape off any that might be embedded and loosen it up. A quick scrub with a stiff bristled nylon brush under running water will remove 99% if not all of any stray grit from even those. The first use of the stone will remove any that might remain.

The stone doesn't glaze either. You are flattening the tips of the abrasive particles by lapping them, not dulling them. The flatter you make them the less deep they will cut without higher pressure. They will still be sharp because of the peaks and valleys formed by the tumbling and rolling lapping grit. Coarser lapping equates to faster cutting with a worse finish, finer lapping equates to slower cutting with a finer finish. You need to strike the balance that you want for your particular stone and preferences. Very soft stones will self-regulate no matter how you lap them if you use much pressure because they will just shed the grit that is taking more pressure to cut. However, if you use very light pressure you can make even soft stones perform above or below their "rated" grit for a short time. How much you can tweak the rating is heavily dependent on the stone.
 
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I swear there used to be a quick reply button...

I don't know what to do right now. I am mainly worried about sharpening wood plane blades. I may get a cheap plane and try it out with the ceramics. It will probably work. Thanks for the help! I didn't mean change my mind but it seems like being still is the best option.
 
Squashfan said:
I swear there used to be a quick reply button...

I don't know what to do right now. I am mainly worried about sharpening wood plane blades. I may get a cheap plane and try it out with the ceramics. It will probably work. Thanks for the help! I didn't mean change my mind but it seems like being still is the best option.
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For the plane blades, you might instead just use wet/dry sandpaper over glass. Woodcraft also sells granite surfacing plates (ground dead-flat to very tight tolerance) to be used as such with sandpaper, and they're not very expensive either. I've got one, and it comes in handy. They might also carry a 'scary sharp' kit setup (float glass & PSA sandpaper, and maybe an angle guide) for sharpening such tools. That'd save you the trouble and worry about changing or damaging your ceramics.

At least a couple 'celebrity' woodworkers (on PBS) also use DMT Duo-Sharp plates for plane blades & chisels, and have occasionally demo'd such use with them on their shows. Those are the interrupted-surface hones, which DMT guarantees to be flat for such uses.

(...and there's a thread in the Tech Support forum regarding the 'Quick Reply' and other issues; Spark turned some of that functionality off for troubleshooting purposes.)


David
 
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The fact is, if you Lap them you change them. The medium and fine stones are formed and fired to get their "grit", only the UF ceramic is factory lapped to make it finer. Spyderco uses a diamond lapping machine because it's the only abrasive truly hard enough to properly lap the ceramic surface. IMO, it's a waste of time to do it yourself.

I was recently sent of box of chisels and plane blades, I have been testing between my Nubatama, Kohetsu, Naniwa Professional, Shapton Pro, and various or ther synthetic and natural stones. The Naniwa and Shapton Pro are both ideal stone sets for the task but the Shaptons are just a bit better. I would recommend some shaptons to reduce headache and damaged stones.
 
SiC is plenty hard enough to lap the Spydercos. And at least the factory UF 3" x 8" bench stone is NOT lapped, it's ground with a diamond cup wheel, the tooling marks are visible.

And you can make the Spyderco ceramics perform as good as or even better than original with no issue. Texture is just texture. This is why loose grit lapping is better than lapping with wet/dry or a diamond plate.
 
Flatting it using a dmt stone will eat it up. But it worked. Plus, this leaves diamond particles embedded in the ceramic stone. How long these remain to give their affect? I'm not sure but for several knives. I would still go with the SiC loose grit slurry starting with something around 300 grit and with this do most of the work(using plenty of H20 & try to capture some of this slurry). Then finish off lightly with a grit around 5-600. Then leave it and do a few knives and see how it finishes these off. Good Luck, DM
 
Yeah embedding does not happen in hard stones. Asking Sal would be pointless, these guys aren't planning to go into production. And actually I remember him mentioning it before - they don't even do it in-house. They send the UF stones for grinding at a vendor.
 
Here is just one link from a quick google search:

http://www.bladeforums.com/forums/showthread.php/420097-Sypderco-Ultra-Fine

Hardness of the Spydie ceramic used in the UF is spec'd by Sal as 9.22 Moh's. SiC is 9.5. Diamond of course is 10. The scale however is not linear, so the actual difference in hardness isn't easy to quantify. Regardless, SiC can lap the UF. I and many others have done it. It works. As you can read for yourself, the UF stones are ground, not lapped. With a diamond cup wheel, as I can see for myself by looking at the stone. (On my UF bench stone I left one side factory finished and lapped the other).
 
As a final note, if you are going to be sharpening plane blades most of this discussion is academic. You'll almost certainly want something with a bit more cutting power than Spyderco ceramics, Jason is dead correct on that one. I can second his recommendation of Shaptons at least for the coarser stones, up to around 2k at least would be good. You can use your Spydies for the finer finishing with no problem.
 
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