What sizes do you prefer. Kinglsley has 10 mesh sizes. I have a glazed Spyderco stone to fix and some Indias.
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Lapping stones for flatness
- Thread starter trailhunter
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What sizes do you prefer. Kinglsley has 10 mesh sizes. I have a glazed Spyderco stone to fix and some Indias.
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Get the coarsest grit you can. Don't waste the diamond on India stones--you can use loose silicon carbide grit on conventional vitrified bond stones. You only need diamond grit for sintered ceramics.
Thanks, they sell 3 grits for cheaper what do you think 100, 325, and 1,200?Get the coarsest grit you can. Don't waste the diamond on India stones--you can use loose silicon carbide grit on conventional vitrified bond stones. You only need diamond grit for sintered ceramics.
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Your call, but even coarse diamond leaves a pretty fine finish.
David Martin
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As you work your stones, I would have a spatula handy and capture the slurry and put it in a small jar. For later use on strops. The grit size is not so important. DM
For years I've used 80 SiC and water on a flat concrete paving stone on Norton India and Arkansas stones and it worked really well. I wasn't too confident in how flat a paving stone is but they are amazingly flat and it seems to be staying flat over the years. Stones come off of it very flat when checked with a good straight edge. It doesn't take very long either.
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related question for
FortyTwoBlades
and others: I have a flat granite tile I use with sandpaper to flatten scales. Can I use the same granite tile with loose SiC grit to flatten stones or will it wear away at the granite and make it dish?
FortyTwoBlades
and others: I have a flat granite tile I use with sandpaper to flatten scales. Can I use the same granite tile with loose SiC grit to flatten stones or will it wear away at the granite and make it dish?
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related question for
It'll dish over time, so no. Use cheap, recyclable glass instead.
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cool thank you! The granite tiles only cost $1 at the flooring store so I will grab another one if I can't find glass.
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Glass "cutting boards" are a good cheap source of float glass in a convenient size. Just get a flat one instead of textured, of course.
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Good idea.
We have one of those textured glass cutting boards in our kitchen, with sort of a rippled water 'waviness' to to the surface. I've never used it and I shake my head every time I look at it. Between it's capability for dulling knife edges and the inherently unflat nature of the textured surface, rendering it unusable for lapping, it may be one of the most useless items in the house.
A few years back, I picked up a couple of rectangular 'candle plates' at Hobby Lobby. They're 9" x 13" or so, made with 1/4" glass. Paid under $5 apiece for them. Had little rubber stick-on 'feet' attached at the corners to keep it from moving around on a tabletop. I'd picked those up to use with sandpaper for sharpening. The edges of the glass were chamfered (1/4" wide or so) on the upper face of the plate, but fully flat to the edge on the lower face. So, I unstuck the little rubber feet from the bottom side and flipped it over to put the feet on the chamfered side, so the fully-flat face was upward. I've since used one of those plates for some small lapping jobs using some 600-grit SiC I had on hand, and it worked pretty well for that.
You can get a very flat granite surface at many home stores very easily and cheaply. Polished granite tile! Bring a straightedge and you can pick the best in the bunch. I've found the granite tile to be much flatter than the glass. (Machinist, a little picky about "flat").
I purchased several float glass pieces and granite tiles some years ago. The glass required too much work to flatten; it was mostly flat in the middle but fell away at the edges.
I purchased several float glass pieces and granite tiles some years ago. The glass required too much work to flatten; it was mostly flat in the middle but fell away at the edges.
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The issue is usually the matter of size. I find it easier to get nice big pieces of glass for cheap than it is to get granite in comparable dimensions. The mechanism of the lapping will end up flattening the glass at the same time, really. While you need to replace the glass eventually when it gets really hollowed out, the region where it's actually being worked/worn should theoretically be very flat.
With a good quality granite tile the backside is just as flat as the polished side so use it too. When lapping stones I always run off the sides of the tile to try to wear the tile evenly. Yes it makes a mess so put a bigger piece of cardboard under the tile to catch the mess and make cleanup easier.
I suppose I am a little biased since I have a brick saw - I just use it to cut the granite into any size I like. However, a 12" × 12" tile is not really that unmanageable. And it will take longer to go out of flat due to lapping also if the wear is distributed over as much surface as possible. And you can absolutely use both sides, as Diemaker mentioned.
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I wasn't aware of this. How can one tell?
Good documentation of the stone is about the only way to be but experience will tell you which ones to stay away from. The US has a lot of high-quality granite deposits but since they are pink or grey with some blacks finding them in tile form is rare, very rare, but great for surface plates. Probably the safest way to go is black granite, preferably Black Galaxy, or Blue Pearl. Both are pretty hard and commodity stones so on the low end of $$.
We all know glass is double-sided so I was just saying so are good quality granite tiles. In fact, IMO the polished surface of either doesn't work as well as one with some texture. The texture seems to hold the abrasive better so it rolls instead of skidding around doing a better job.
The three plate method of lapping is getting pretty extreme but worth knowing about. For more info search "three plate lapping method" on YouTube. This one is my favorites but don't be shy about speeding through much of it as it is long and at least 4 episodes.