The Grand Unified Grit Chart

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Unfortunately, I can't do much that way. The number of compounds that fit into those general colours, and the variety of grit sizes within those compounds are MASSIVE. There really *is* no defined grit number for, say "green" compound.
 
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Since some folks have recommended Congress Tools's "Moldmaster" stones for the Edge Pro, I contacted them and asked about their stones. Their response:

Dear Patrick,
Thanks for your inquiry. Approx. micron size for grits follows:
150 grit - 100 micron
240 grit - 60 micron
320 grit - 45 micron
400 grit - 40 micron
600 grit - 30 micron
Our stones are manufactured for industrial applications, so we do not have much knowledge concerning knife sharpening applications. I understand that our stones have been recommended on several blogs and articles, and we have received many orders for our MoldMaster and Ruby stones in the coarser grits for initial rough cut and our FLEX stone in 400 or 600 grit for a finishing stone.
Best regards,
CONGRESS TOOLS, Inc.
Mark Froelick

In a message dated 5/19/2012 7:43:04 P.M. Eastern Daylight Time, info@congresstools.com writes:

Name: Patrick Roos
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Email Address: loonybin@ar15.com

Comments: I am interested in some of the Moldmaster stones and I have some questions:

1) what micron size are the 120, 150, 240, 320, 400, and 600 grit stones?
2) how effective are these stones for sharpening knives made of s30v, D2, and CPM-M4 (I'll be using an Edge Pro Apex sharpener)?

Thanks!
Patrick
 
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Updated with Moldmaster Info, thanks!

gcrevd.png

FULL VIEW
 
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Hi Komitadjie, loonybin,

Thanks for the update to the Grand Unified Grit Chart! :)
I own some Moldmaster stones, so it's nice to see them in the GUGC.

Sincerely,
--Lagrangian
 
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Hi Komitadjie, loonybin,

Thanks for the update to the Grand Unified Grit Chart! :)
I own some Moldmaster stones, so it's nice to see them in the GUGC.

Sincerely,
--Lagrangian
How do you think the compare to the EP stones? I ordered 120, 240, 400, and 600, but didn't realize that the 600 was such a large micron size. If I had known that, I would have ordered the 320 instead of the 400 to basically split the difference between the 240 and the 600.

Komitadjie, I'm a little confused on the EP list, as you have the #2000 listed as a larger micron than the #1000. Is the 2000grit tape a higher micron size than the 1000grit stone?

Also, I've emailed him back asking for micron size for their Orange EDM, Ruby and Flex stones as well.
 
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I WISH I had a decent answer on that one, Loonybin! I've been trying to get a SOLID answer on the EP grit sizes since I started this chart, and I haven't been able to actually get any solid information. I don't think Ben Dale actually knows, at least he hasn't responded to my queries on the topic. The numbers on the tapes come from the EP website, so I'm at least a bit more confident on those. The numbers I have for the EP stones come from an older spreadsheet that I incorporated right back at the beginning of this. I honestly suspect that the numbers listed there are quite a lot coarser than reality, based on how they cut.
 
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Next question: Moldmaster 240 grit stone is 60 micron, and the EP 220 grit stone is 63 micron. Since the micron size is basically the same, will the Moldmaster stone cut better due to being SiC instead of AO, or will the EP stone still cut better due to being larger micron size?

Also, your latest full size image doesn't work.
 
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Should be fixed... that was odd, even in the IS account it won't load... but it DID when I put it up. Odd.

The three-micron difference likely isn't going to matter THAT much, although I have no empirical evidence to back that up.
 
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Should be fixed... that was odd, even in the IS account it won't load... but it DID when I put it up. Odd.

The three-micron difference likely isn't going to matter THAT much, although I have no empirical evidence to back that up.
So the Moldmaster stone should cut better because it's SiC, then?
 
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I would think so, the SiC is likely to both cut and break down a little faster... I've never played with the Moldmasters myself, so I really can't give a definitive answer. I'd sure be interested in finding out, though!
 
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The edge pro stones are made by Boride Abrasives (AS-9, AM-K, CS-HD, according to a Boride manager) and use FEPA standard.

I WISH I had a decent answer on that one, Loonybin! I've been trying to get a SOLID answer on the EP grit sizes since I started this chart, and I haven't been able to actually get any solid information.

Email Betsi Burns, the sales and product manager at Boride.
 
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The FEPA-F standard WOULD make a fair bit of sense, given that a number of people have commented that the listed values are quite a bit coarser than the stones actually cut...

I'll update the chart when I get home this evening, that might finally clear some of that mess up. I must have just completely missed your first posting of that, sorry. :)
 
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And on the 8th day God created a grit chart...and used you to do it...Do you have any idea how many times ive asked myself these questions...
 
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Hey, glad it's helped 'ya out! :)

New revision, I've re-sorted the EdgePro stock stones to reflect the response from Boride that they are FEPA-F graded. This casts some doubt on the numbers for the tapes, given that the 2K tape is now considerably more coarse than the 1K stone... So I've moved the tapes to approximate values.

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FULL VIEW
 
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You may want to make the Spyderco values approximate, they are all 20+ micron sized particles, and the difference in cutting action is from binders, firing processes and surface finishes. You would have similar micron equivalency issues if you added natural stones.
 

aznpos531

I like sharp and pointy things...
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First of all, thank you Komitadjie and all the contributors for making this chart. It's been very helpful in selecting stones for myself.
Couple questions about this chart.

Are the grit v.s. micron sizes still more or less the same for the Shapton Glass Stones versus the older Pro Series Stones?

Does anyone know what is the approximate grit size is for the Spyderco diamond rods?

Thanks!
 
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Glad it can help 'ya out!

I haven't heard a solid micron size given for the Spyderco diamonds as yet, unfortunately. It seems that the spyderco stuff in general is very hard to grade. The next revision of the chart will list them as approximate values, I think. I BELIEVE the sizes are roughly the same between the Pro and Glass, although they cut very, very differently due to binder changes as I understand.
 
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