Spyderco Fine Benchstone - Out of Spec? - My paper thickness test

J

J Thomas

Joined
Feb 26, 2003
Messages
67
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I have a Spyderco Medium Benchstone (302M) and a Spyderco Fine Benchstone (302F).

I was using both tonight to touch up a blade and noticed the Fine stone "see-saws" when laying flat. What I mean is if I push down on one end it rises, to me, a fair bit. My Shapton Glass stones do not do this.

Putting a straight edge to it, definitely a bow (light shows) and I did this test.

Lay the stone on a flat surface and see how many sheets of Xerox Premium Multipurpose Paper I can slide under each edge, (paper spec on the wrapper is 96 bright, 24 lb.).

I can slide 3 sheets easily under each edge about an inch deep, 4 sheets make it but starts to be snug. All my Shapton Glass stones, cannot slide even one sheet under either end.

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I wonder if this is within spec and should be sent back to Spyderco, or, is this just the nature of this type of stone?

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While doing this I tried the Medium stone and could get one sheet of paper an inch deep under one end, however, the other side blocked the one sheet.

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I know paper is different thicknesses, I wonder how thick 3 or 4 pieces of the above paper is with a micrometer ... how many thousands is the Fine stone "off" if it is indeed out of spec from the factory?

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Standing them side-by-side the Fine is 1/8" of an inch taller ... hmm, I either got too much of one or not enough of one ... I wonder which it is?

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Hi,
yeah, that is too much out of flat, it should be perfectly flat
there are reports of the sharpmaker rods also being bent and of spyderco providing replacements

internet say,
average copy paper thickness is 1/100mm or 100 microns, so times 3 its 300
the spyderco medium rods are about 12.5 microns
the spyderco fine stones are about 6.5 microns
P150 grit is about 100 microns
and P50 grit is about 330 microns
the knife edge apex is about 1 micron wide/thick

the stones should be at least as flat as the grit/micron rating
 
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Thank You for the feedback, information and direction. Using your help I came up with the following:

1) http://www.casepaper.com/resources/...ing_wp_cron=1468669789.8515551090240478515625

2) https://www.evi.com/q/.0045_inch_equals_how_many_microns

3) http://www.woodcraft.com/product/835911/spyderco-bench-stone-2-x-8-fine1800-grit.aspx

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1a) 24 lb = .0045

2a) .0045 = 114.3 microns

3a) 114.3 x 4 papers = 457.2 microns, this is under the Spyderco spec guarantee of .020 = 508 microns

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Thank You for the help in determining that the stone is within the spec that Spyderco gives as their guarantee of flatness.

I appreciate the help - Thanks.

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I got my stone very flat. Within .001-.002" using a coarse and fine diamond stones. Which I would not recommend using. Douglas method was better and I agree with his time and effort required. I used water to keep the dust down. He's right you'll never have to flatten it again. The Spyderco's are good stones, just some don't come flat. Mine turned out finer on the one side so I left it and now have essentially a stone with two different surfaces. Good luck, DM
 
David Martin said:
I got my stone very flat. Within .001-.002" using a coarse and fine diamond stones. Which I would not recommend using. Douglas method was better and I agree with his time and effort required. I used water to keep the dust down. He's right you'll never have to flatten it again. The Spyderco's are good stones, just some don't come flat. Mine turned out finer on the one side so I left it and now have essentially a stone with two different surfaces. Good luck, DM
Click to expand...

Who's Douglas and what's his method? Thanks.

when I got my atoma 400, I lapped the spyderco also and saw it was more bowed on one side than the other.
 
In post #4 Bucket gives a link to another members experience of leveling his Spyderco ceramic stone. His name is Douglas. You can click on that to read. DM
 
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bucketstove and David Martin ... Thank You ... I'm considering the method bucketstove linked to and David Martin helped describe and give insight to. Seems like a fun project to see if I can turn my Fine stone into a combo, Fine/Ultra-Fine.

I appreciate the help and direction.

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Yes, you can do it. Mark the surface of your stone and work slow in grinding it. Checking your progress often and watch for glazing. Set aside a couple of hours for the project. Good luck and let us know about your progress. Your welcome, DM
 
I've flattened a spyderco ceramic before . Not because it wasn't dead flat , Internet told me if I lapped enough it would be a shapton 30k...I don't know if I believe all that and I burnt through a diamond plate doing it ,but by God I have a dead flat ceramic with no saw marks . I'll say this any future spyderco ceramics will not be lapped by me again ever ...They laugh at you while killing your diamond plates. I would send it in before you try to climb that moutain trust me on this .

If you do want to lap it here's how I did it . I started with cheap diamond and I lapped and I lapped . Some progress but the wear on my diamonds was pretty bad . I moved on to power equipment . As in a belt sander , now I know the belt sander couldn't get it flat but it did do the heavy work when I was about 95% there I went back to doing it by hand . Friendly advice if you take power equipment to ceramic wear a mask . Ceramic dust is some nasty stuff .

I lapped an UF stone and just for a reference if the stock UF stone is say equal to an 8k Waterstone (no idea the actual number just a reference point here ) say it was 8k when it got to me . When I lapped it one side acts more like a 12-16k now but it's slower .
 
Personally I'd attempt to send it back and exchange. If its within spec they'll still probably send you a different one and retail the one you had(?).

I lapped mine on one side - used a couple of different base plates for the lapping surface along with 60 grit SiC. Literally crushing the SiC grains down to paste and then adding fresh, along with a lot of water and globs of dishsoap to keep it on the surface as I went.

As it got closer to true flat I used it to completely lap flat a Surgical Black Arkansas a buddy gifted me. Used it on some textured steel plate. Used it with a tile rubbing stone. Believe me those stones are tough. Using the SiC made it less out of true it but completely glazed it as well. Held at a shallow angle to some light you could see it was highly reflective - had essentially lost all ability to grind or polish and was only good for burnishing.

I then (years later) came back to it and used it with a lapidary diamond disk at 180 mesh. These are not like diamond sharpening plates - there is a ton of Nickel on the surface, the diamonds are deeply embedded in the plating. This makes them not so good for sharpening but very good at flattening hard minerals while still leaving some texture. This disk I used is 8" diameter bought at Kingsly North for about $50 (also works fantastic for flattening waterstones).

This flattened it true to within a pencil line thickness as the whole thing basically cleans up simultaneously. It also left it with a respectable amount of surface texture, so it works good for final sharpening again.

Working on them is a pain in the butt and you have to be ready to do some subjective tinkering to get it where you want it in terms of surface texture, I don't think I'd tackle another knowing what I do.
 
Unless you're sharpening something specific that requires it to be dead flat (as possible)... I wouldn't worry about it.
 
One your medium stone they wear a little quicker ,well not quick but they wear faster than the UF , I was expecting the pain of flattening the UF ,but actually the medium wasn't that bad . It's not waterstone easy though .
 
I'm glad I did mine. As it turned out good. Especially, since I ended up with a good flat stone and 2 different textures on one stone. That saved me from buying another ceramic stone for 60$. Plus, I learned some things. Learning is not cheap. DM
 
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