Ceramic stone flattening, and increasing grit size?

L

LeatherSnake

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Aug 4, 2016
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Ok this might be a stupid question (which it is) but is it possible to increase the grit size of my spyderco double stuff or my DC4 (or CC4) stone by lapping it with a diamond plate? If so what grit should i use to make the ceramic stones finer?
 
Grit size is grit size you can't change that .You can flatten a stone or clean it but not change grit size.
 
In cases of frangible abrasives - especially softer hones - this is true (effective grit size isn't very alterable), but for the fused alumina of the Spyderco ceramics and some other very hard hones/stones this is possible. The coarser the stone surface is, the higher the cutting speed and coarser the resulting bevel finish. The converse is also true. Personally I prefer loose grit SiC for resurfacing, but others have used differing methods. There have been several fairly extensive threads on the subject - use Google to search BF and they should be very easy to find.
 
LeatherSnake said:
Ok this might be a stupid question (which it is) but is it possible to increase the grit size of my spyderco double stuff or my DC4 (or CC4) stone by lapping it with a diamond plate? If so what grit should i use to make the ceramic stones finer?
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Hi,
Why do you want to do it?

The spyderco fine is ~6 micron, and diamond plates in that grit and higher are expensive , very tiny ones are ~$30
There are thin diamond polishing plates on ebay in 3000 grit under $10 ... which might be around 5 micron ...
..
Interesting info over here
Spyderco Fine Benchstone - Out of Spec? - My paper thickness test
Finished lapping Spyderco Fine Benchstone ... not too shabby
 
LeatherSnake said:
Ok this might be a stupid question (which it is) but is it possible to increase the grit size of my spyderco double stuff or my DC4 (or CC4) stone by lapping it with a diamond plate? If so what grit should i use to make the ceramic stones finer?
Click to expand...

When you say

increase the grit size
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you mean to make the rating a larger number and the surface more refined?

It is possible, you will need a diamond plate or loose diamond grit on a steel plate to do so. I'd imagine something in a 260-360 mesh would be the finest you'd want to go - any finer and the surface is liable to glaze.

Do a search on the forum for "lapping a Spyderco" and you'll get some good info.
 
LeatherSnake said:
Ok this might be a stupid question (which it is) but is it possible to increase the grit size of my spyderco double stuff or my DC4 (or CC4) stone by lapping it with a diamond plate? If so what grit should i use to make the ceramic stones finer?
Click to expand...

I've lapped Lansky Fine & UF ceramics, a Spyderco DoubleStuff hone (both sides), and my DC4. If you're looking to make the hones finer in finish (which DECREASES the effective grit size; the grit rating is a higher number for smaller effective grit), I know from my own experience with the Lansky and Doublestuff that a Coarse DMT plate (8" Duo-Sharp @ 325 mesh/45 micron) or finer will definitely do it. An XC might also do it to some degree. I did all that lapping with the ceramic hones immersed in water. With my DC4 hone, I used an inexpensive aluminum oxide stone with some 600 grit SiC abrasive applied to it, and some water to make a slurry. The DC4 also came out finer than original, though not quite as fine as the results on my Lansky and DoubleStuff hone done with the Coarse DMT. The DoubleStuff came out likely finer on both the (previously) Medium and Fine sides than Spyderco's UF hone. I'd not recommend going any finer than that; you'll end up with a glass-slick hone that will do little more than some very fine burnishing/polishing, which is fine for some jobs, but might be a little too limited in effectiveness otherwise.

If attempting it, I'd also not start any finer than around that 'Coarse' level of ~320 or so, and I'd actually recommend starting at an XC grit instead (DMT's XC is 220-mesh/60 micron). If you start out too fine, it'll be a ton of work to re-do everything and bring it back to a coarser effective grit (if it can be done at all).


David
 
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As in increase "grit size" I mean as making the stone smoother and finer than coarse. People complained how coarse the DC4 ceramic stone is. I forgot who the guy was but he lapped the stone by taking the diamond plate off of the DC4 and lapped the the stone, thus making it into a flat, smooth and finer stone on one side of the stone. So the question is, should I start with a coarse or a fine diamond plate? Also could i use 400 grit to lap them instead of 300?
 
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LeatherSnake said:
As in increase "grit size" I mean as making the stone smoother and finer than coarse. People complained how coarse the DC4 ceramic stone is. I forgot who the guy was but he lapped the stone by taking the diamond plate off of the DC4 and lapped the the stone, thus making it into a flat, smooth and finer stone on one side of the stone. So the question is, should I start with a coarse or a fine diamond plate? Also could i use 400 grit to lap them instead of 300?
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I'd still start with a coarser diamond plate (300, if that's the coarser of what you've got). Chances are, the resulting finish on your DC4 will still be finer than what it is now. The danger in starting with 400 or finer is, you might produce a finish on your DC4 that's a lot smoother/finer than you want. That's the usual tendency in lapping ceramics, as they almost always finish finer than expected, unless you're starting with an extremely coarse lapping stone/media. If you do still find the 300 actually leaves it coarser than what you're wanting, it'll be easier to follow with the 400 to fix that. The converse is, it's much more challenging to take a ceramic that's too smooth back to a rougher finish, UNLESS you do have access to some extremely coarse (and sufficiently hard) grinding media.


David
 
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Thanks David, I have intentionts to make my DC4 or my Spyderco to be very fine, so I might find a 400 grit diamond plate. If I tried to lap the fine side of my spyderco doublestuff, it might conpare to their UF ceramic stone except pocket sized!
 
Its easy to do harm to a diamond plate when lapping ceramics. Personally I would get a 6" or 8" diamond lapidary disk. It isn't much good for sharpening but will do a great job on any future lapping chores and on any stone. They can be had for about $50. Use a lot of water and I use a bunch of dish soap as well. The lapidary disks grind ceramic far more effectively than diamond plates made specifically for sharpening.

Edit to add:
every so often wipe it dry and hold it a shallow angle to a light source, this will give you a real good look at the surface texture.
 
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You use it by hand just as you would a DMT plate or similar. I set mine on a rag in the bottom of the sink and let a slow trickle land on it while lapping.

I have a few of them, the 180 mesh is so much faster than my DMT XXC it is no contest and at about 1/2 the price. The XXC DMT or any other DMT is just too expensive to tear up on a project like this IMHO. The lapidary disk is made for work like this.
 
LeatherSnake said:
Also any recommendation for how long i should lap it?
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Draw a hash-marked pattern (crossed diagonal lines), with a Sharpie or similar marker, across the entire face of the ceramic hone to be lapped. Lap until the hash-marked pattern has been completely removed from edge-to-edge. The difference in finish should be pretty obvious as you progress, so it's pretty easy to tell when you've worked the entire surface. You can also check flatness with a steel ruler's edge laid against the hone (side-to-side, end-to-end and diagonally from corner-to-corner).

A (decent quality) diamond plate can do the job on pocket-sized hones with minimal wear to the plate, so long as you work with a lot of water (I'd recommend immersing it while you work) and don't apply excess pressure. The water will keep the diamond plate flushed clear of the material removed, which keeps it grinding efficiently and therefore helps protect the plate at the same time. It'll take a while, but don't give in to rushing the job by leaning into it; that's what will damage the diamond plate. My 8" DMT Duo-Sharp plate finished the job on my DoubleStuff hone with no visible wear. If your hands & wrists are getting too sore & tired after a short amount of grinding, that's likely a clue you're pressing too hard.


David
 
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I have lapped my DC4 with coarse grit sandpaper. It took a few sheets but flattened it. I also did another DC4 with coarse diamond plate. Both methods resulted in a very smooth finish, too smooth for me I would have preferred more coarse.


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Spyderco makes the Ultra Fine ceramic by lapping a Fine ceramic, so it is possible. I've lapped the Spyderco UF with a DMT Fine 600 mesh and was able to improve the polishing qualities but I think loose diamond grit as HeavyHanded has recommended would be your best bet. The diamond plate was almost completely worn out at the end of lapping BTW.
 
I'm not a fan of cheap sharpening stones or plates. But in this case, maybe it would make sense to buy one of the Harbor Freight diamond sets. I think they are around $25. You'd probably ruin the coarse one doing a small ceramic stone or two (like the DC4), but it might be worth it.

Brian.
 
LeatherSnake said:
So what would result if I lapped it to 400 grit?
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If lapping with DIAMOND on a hard plate, you'd likely be OK, though the finish would still likely be very fine at 400. It only works because diamond is about 3X as hard as the aluminum oxide in the ceramic, and the hard steel plate behind it will make it work most aggressively. Trying to lap a sintered ceramic with sandpaper (SiC or AlOx) is sort of asking for trouble. Though SiC grit is hard enough by itself (about 25% harder than aluminum oxide), the paper backing on sandpaper is essentially cushioning the grit and therefore diminishing the aggressiveness of it, and it'll leave an effectively finer finish, maybe too fine. SiC is better used with a hard backing immediately behind it (steel plate, stone, etc). SiC is also known to be relatively brittle, breaking down in size with use and therefore lending an additional tendency toward a finer finish for the stated grit size. If the sandpaper is AlOx (aluminum oxide), it essentially shouldn't work at all, as the abrasive is no harder than the sintered aluminum oxide in the ceramic hone. I tried it with AlOx sandpaper once, and it didn't produce any swarf at all from either surface, and it felt like rubbing two sheets of glass against one another.


David
 
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bgentry said:
I'm not a fan of cheap sharpening stones or plates. But in this case, maybe it would make sense to buy one of the Harbor Freight diamond sets. I think they are around $25. You'd probably ruin the coarse one doing a small ceramic stone or two (like the DC4), but it might be worth it.

Brian.
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They're even cheaper than that. I have three Harbor Freight diamond hones (180, 260, 360), purchased as a set for $10. They're definitely expendable, though they're also mounted on too-thin plastic backing slabs that aren't flat. If using them for lapping, I'd first remount the metal diamond plates (also very thin themselves) on something flatter and more substantial. I've considered doing it with mine, but it's hard motivating myself to expend that much effort for hones that cost me about $3 apiece. HF also sells a block-type diamond combo-hone with hones on 3 or 4 sides; it may be flatter, but I don't know for certain.


David
 
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