Ceramic stone flattening, and increasing grit size?

This is where I picked up my disks. I think for the price they are priceless. The grinding/lapping action of the 180 mesh was head and shoulders over the DMT XXC. While nothing will make "short work" of a job like this it came darn close. The finish it left was probably right between the original Fine and Ultra fine. I went over the ceramic briefly with the 320 and again, it was pulling off white yet not leaving a glazed finish. At this point I believe it to be in the realm of a UF (with nothing to compare from the factory). Going finer caused the plate to begin "sticktioning" to the hone and I stopped.

Still, the 180 mesh does a great job on hard to lap waterstones, can true up a SiC combination stone etc. I'm sure it will begin to lose its zip at some point, but up to now it keeps getting better.




http://www.kingsleynorth.com/skshop/product.php?id=88638&catID=1140
 
mete said:
Grit size is grit size you can't change that .You can flatten a stone or clean it but not change grit size.
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We've been over this same subject numerous times like eKretz mentioned. I've done my Spyderco fine ceramic stone on one side as it was unlevel and I was wanting to achieve the double benefit of a finer finish like the that of the ultra fine. Without having to purchase the ultra fine stone for a $100. I had good success doing this using a worn coarse diamond stone and a fine diamond stone to finish. Still, I'm firmly in the camp with Mete. The ceramic stones surface will change (and you will level it) to feel finer but it's superficial and shallow. It will impart a finer finish to your tools edge. (finer scratch pattern) And it will do this for a Lot of sharpening. Likely for Years. But it's still only on the surface. Yet, done right I think the savings is present and you won't have to purchase that other stone. As this is exactly all Spyderco did to achieve their ultra fine stone. Changed the surface. DM
 
Don't count on the HF box hone being any flatter. The batch they have at my local store is all wonky. I tried 3 and returned them, they had ripples in them all.
That being said, I have had them flat, bUT not consistently.
Russ
 
Ok, since I don't have a grinder of some sort. What diamond stone do you reccomend to lap my spyder or my DC4?
 
You don't need a grinder, the diamond plates/disks etc all will work fine by hand. Plan on it taking a solid half hour of work, maybe less if your ceramic plate is close to flat to begin with, maybe longer if your diamond plate isn't aggressive. Plenty of water and move in a figure 8, circles in both directions etc.

I do have a horizontal grinder for my disks, but they work fine by hand. David managed to do his with DMT hones and not harm the DMTs, most folks find they beat up their diamond hones pretty good doing this sort of thing. That's why I recommend the ones made to work on hard stones.

DMT now makes a "hard-coat" diamond plate for sharpening ceramics and high carbide steels, and is incorporated into their lapping plate. It would probably work great too but they are mighty pricey.

On the cheap I'd buy the block from Harbor Freight and move the stone around a lot on the surface to keep it from grinding unevenly.
 
I got a set of cheap diamond plates here:
selection of cheap diamond plates

For the heavy lifting i got a 60 grid in A4 size (11.4x8.2 inch) :thumbup: . After my first Spyderco 302F it was smooth and ready for a bit more pressure... After the second Spyderco it was a bit slower, no missing grid whatsoever. I use oil and i put a papertowel under the plate on my ceramic tile, a bit wet so it's sticky. If you regularly put a bit of oil in the middle, the swarf flows outwards, ready to soak the papertowel. I find this faster and still cleaner than any action in the sink. I continued with 8x3" plates in 150, 240 and 400 since i already have them. Use permanent marker, pencil is lost far earlier than the stone is flat... :(

Next time i will use loose grid siliconcarbide F80, F220 and F400. My best guess after going through an arkansas stone is that it's ten times faster. :o
 
hein31 said:
I got a set of cheap diamond plates here:
selection of cheap diamond plates

For the heavy lifting i got a 60 grid in A4 size (11.4x8.2 inch) :thumbup: . After my first Spyderco 302F it was smooth and ready for a bit more pressure... After the second Spyderco it was a bit slower, no missing grid whatsoever. I use oil and i put a papertowel under the plate on my ceramic tile, a bit wet so it's sticky. If you regularly put a bit of oil in the middle, the swarf flows outwards, ready to soak the papertowel. I find this faster and still cleaner than any action in the sink. I continued with 8x3" plates in 150, 240 and 400 since i already have them. Use permanent marker, pencil is lost far earlier than the stone is flat... :(

Next time i will use loose grid siliconcarbide F80, F220 and F400. My best guess after going through an arkansas stone is that it's ten times faster. :o
Click to expand...

The Arkansas should always be much faster to lap anyway, as it's grit (novaculite) is about 1/3 as hard as the alumina in a ceramic hone. I've used inexpensive SiC and AlOx hardware store stones to lap an Arkansas stone of mine; it was orders of magnitude easier by comparison to lapping ceramics, taking only a few minutes' work.


David
 
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I've lapped / leveled several Arkansas stones and they are not as time consuming as a Norton fine India. DM
 
My point was not to compare an Arkansas stone to a hard ceramic like a Spyderco. :confused:

I humbly suggested, that for all kinds of heavy work on extremely hard or tough stones a lapping solution is preferable to a grinding with diamond plates only. The reason is simple: if you put a loose grid abrasive like siliconcarbide onto a hard and tough surface like another hard stone you can apply reasonable pressure which speeds up the process. If you use a diamond plate only you will always limit the downward pressure since you don't want to wear out the plate. Generally three-body abrasion is the preferred solution here, since two-body abrasion is limitted in it's efficiency.

Even if you use other stones without loose grid abrasives you can apply much more pressure. Depending on the characteristics of the other stone more pressure normally leads to three-body abrasion, as most waterstones release more than enough fresh grid.
 
hein31 said:
My point was not to compare an Arkansas stone to a hard ceramic like a Spyderco. :confused:

I humbly suggested, that for all kinds of heavy work on extremely hard or tough stones a lapping solution is preferable to a grinding with diamond plates only. The reason is simple: if you put a loose grid abrasive like siliconcarbide onto a hard and tough surface like another hard stone you can apply reasonable pressure which speeds up the process. If you use a diamond plate only you will always limit the downward pressure since you don't want to wear out the plate. Generally three-body abrasion is the preferred solution here, since two-body abrasion is limitted in it's efficiency.

Even if you use other stones without loose grid abrasives you can apply much more pressure. Depending on the characteristics of the other stone more pressure normally leads to three-body abrasion, as most waterstones release more than enough fresh grid.
Click to expand...


I totally agree. In this case though...the silicon carbide may be harder than the ceramic plate, but it isn't tougher. The additional amounts of force needed to get the SiC grinding also break the mineral down very quickly. I used 60 grit SiC (initially) on my Spyderco Fine, and it glazed the surface to a nice polish. The stone was useless for anything but burnishing.

If one had the need to do this sort of thing or had/were planning on getting a Kanaban with diamond grit, I'm certain lapping with lose diamond or CbN would be the way to go.

I noticed doing mine that the fixed abrasive of the diamond actually did a very good job on the ceramics where on a vitreous stone they'd glaze the surface. I think it comes down to the ceramics needing to be surface cut in order to function properly as the abrasive grains in the body of
the material don't really do any cutting of themselves - is all a function of the surface treatment and the use of alumina is just to make a super tough material that can hold that texture while working hardened steel.
 
Loose silicon carbide grit is frangible guys. You need to use it properly if you want it to cut quickly when lapping something that is near its own hardness. This means rinsing away the old and refreshing with new grit very frequently. If you don't do this, you will effectively be lapping your hone much finer than the grit you start with. Obviously, loose diamond or CBN would be optimal in terms of cutting speed and would not require as frequent of refreshing either.
 
Though you can, technically you cannot lap ceramic with SiC. The difference in hardness does not allow proper cutting action of the abrasive so you get something more like burnishing.
 
Yes one can - I've done so several times for myself and for others - but as I already stated, the grit needs to be refreshed very frequently. If it is allowed to break down it will basically just polish - resulting in a glazed ceramic hone. Keep it fresh and cutting well and it will do just fine. It would admittedly be much less time consuming and more efficient use a loose diamond grit.
 
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