Sharpening stone grit sizes

[Honest John]

Well I'm confused! (Not for the first time) I bought a set of three water stones from Rutlands some time ago when they were on offer. They were marked at 600, 1000, and 3000. Some time before that I also bought one of those Trend mega cheap diamond stones that they were clearing at a stupidly cheap price. That seems to be graded differently. The Axminster Rider diamond stone that I am considering is double sided at 300/1000 and considered as coarse and fine. Now a diamond rated as fine and marked as 1000 is a different beast to a water stone rated as a 3000........ And I understand that some people use water stones at 6000 - 10000. Just to add to my confusion, some manufacturers state the micron size of the diamond particles. How does this relate to the grit size? My understanding of sandpaper grit sizes seem simple enough, but goes a bit haywire when the same rationale is applied to water stones and diamond stones.
If I was shape the primary bevel on a fast cutting 300 diamond plate, then turned it over to the 1000 side to refine, what size water stone should I go to next? My coarsest water stone marked at 600 doesn't seem as abrasive as my 1000 rated diamond?

 

[MIGNAL]

Your Trend isn't 1,000G. It's something like 320 and 600G. Through use it will get finer than those numbers though. I've had one for a few years and I rate (at a guess) the 600 side is near to my 1200G Eze lap,that's just through wear. It started life at 600G.
Your 3,000G waterstone will be finer. I don't bother. I go from my 1200 diamond to a strop, even though I have a few finer stones.

 

[Phil Pascoe]

Find out what works for you, and ignore any grading.

 

[Jacob]

You need one fine oil stone.
You need to grind occasionally, either on a coarse oil stone (hard work) or on a machine.
You could add a strop (leather stuck on a board).
You don't need anything else.
These will last you for life - total expenditure less than £20 for life if you do it entirely by hand (plus oil), but most people have a grinder of some sort, which will crank the cost up.
Whatever you do don't buy jigs or water-stones - these are a crazy recent fashion and will make life really difficult, as you seem to be discovering!

 

[Phil Pascoe]

Groundhog day ...

 

[Random Orbital Bob]

Groundhog day ...

 

[woodbrains]

Hello,

Unfortunately, there are 3 main grading systems for abrasive sizes, and they do not correspond. The European one we know P and F followed by a number, (wet and dry paper commonly use them) the American one CAMI and a Japannese one. So if you try to compare a Japanese water stone to a diamond plate, usually made for the American market, things look a bit strange. So micron sizes are used to simplify things as they are used as a conversion factor, though only approximate, due to particle shape and variances in particle size in the abrasive. So IIRC fine India stone is about P340 g in European sizes, or about 42 micron. Not fine at all in fact, though some here refuse to admit. 6000 grit Japanese stone is about 1.5 micron. 8000 about 1.2. Tormek honing paste is a mix of abrasive particles which acts at about 3 microns when it breaks down in use. Hard black Arkansas stone about 7 microns, So you see the micron size is useful for comparing dissimilar grading systems. Euro and CAMI run about equal until approx 320 grit when they part ways. ( all from memory so forgive if not 100percent accurate)

Hope this helps.

Mike.

 

[memzey]

Just to help complicate matters a little bit more, a hard black Arkansas stone (which is a type of novaculite) will sharpen more like an 8,000 grit Japanese stone as the abrasive value is also determined by the density of the particles (as measured by the specific gravity) rather than purely their size. You have opened up a can of worms John!

 

[Jacob]

The old system was "coarse," "medium", "fine". I'd stick with that - it worked.

 

[AndyT]

At this point in the discussion BugBear usually posts a link to a comprehensive conversion/comparison chart which actually answers the question the OP put...

Paging BugBear, are you there?

 

[CHJ]

Something like this>>>>

 

[AndyT]

Indeed!

BB can have a lie in this morning.

 

[Glynne]

Thanks Chas.
I won't be using this for woodworking but I'll be able to annoy the hell out of my son (precision engineer) who is forever bombarding me with technical details as to what he does.

 

[woodbrains]

Hello,

http://www.evenfallstudios.com/metrolog ... isons.html

Here is a simple chart, that is useful, there are loads more in depth and comprehensive charts, but for a quick idea without being too technical this OK .

Mike.

 

[bugbear]

You need one fine oil stone.

What scale are you measuring "fine" on? :lol:

Actually, having seen "a few" of Jacob's many previous posts on this topic, it's pretty much certain to be a Norton India so-called-fine, which is CAMI(USA) 280, FEPA (Europe) approx 300, 43 micron (actual particle size in SI units). A bit coarse but usefully fast IMHO.

To answer the OP; Punxsutawney Phil says:

http://sharpeningmadeeasy.com/grits.htm
http://www.fine-tools.com/G10019.html
http://www.evenfallstudios.com/metrolog ... isons.html
https://docs.google.com/spreaadsheets/d ... edit#gid=0

Mod Edit:- Last google link error ?

But particle size isn't the only thing that matters; uniformity of grit size is very important, since the cutting rate is controlled by the average particle size, but the scratches are determined by the largest particles. Shape-sharpness of particles obviously matters too.

BugBear

 

[MIGNAL]

It can only be a rough guide as far as diamond stones are concerned. My experience (although a little limited with diamond) is that the cheaper plates lose their edge much faster than the better quality type. That's just through using two of the Trends plates and an Ezelap. Doesn't necessarily mean that the Trend is a poor plate, just that it will end up at a much finer grit than stated.

 

[Jacob]

You need one fine oil stone.

What scale are you measuring "fine" on? :lol:

Actually, having seen "a few" of Jacob's many previous posts on this topic, it's pretty much certain to be a Norton India so-called-fine, which is CAMI(USA) 280, FEPA (Europe) approx 300, 43 micron (actual particle size in SI units). A bit coarse but usefully fast IMHO.
....

You could be right , but I've also got a finer one for occasional use. Actually I've got several but if it came to it "coarse, medium and fine" are all I (like most people) really need.

I've seen "a few" of these posts on sharpening minutiae too!
I only post to remind people, especially beginners who just want to do woodwork, that they don't have to follow any of the modern sharpening crazes and could save themselves a lot of time and money.
It's a separate hobby and not really necessary for woodwork. Or cooking for that matter - when you look at the knife stuff! :shock:

 

[ED65]

Easy to get confused when it comes to this subject John! In addition to the competing grading systems that you need a table to check against, it's well know that various products aren't the same even when they're rated the same on paper. Sometimes the difference is slight but other times it's really stark. This naturally makes for some confusion because people think they're not grasping something obvious when in fact the problem is as the manufacturer's end.

And I understand that some people use water stones at 6000 - 10000.

Yeah but they're silly. This will ignite a furious debate in some circles (possibly here too) but generally it's a waste of time to use stones that fine unless the goal is the appearance of the bevel and not the sharpness of the edge.

If I was shape the primary bevel on a fast cutting 300 diamond plate, then turned it over to the 1000 side to refine, what size water stone should I go to next?

Take your pick! It literally doesn't matter what you use next as long as you're happy with the how things go and with the results. One person might go 1000 > 4000 > 8000, another will hit it briefly with a 3000 and get back to work, and of course someone out there would be happy to use the tool straight after the 1000 diamond plate.

Since I recently got a 1000 diamond plate to try out I can say that I would plump for going straight to a strop (loaded, not bare). I tested this out the other day to definitively check and I'm more than happy with what it'll do on a plane iron. I might go to more trouble for a chisel, depending on the day and what direction the wind is blowing. More seriously it would depend on what I was using the chisel for, for fine paring I think I'd use something finer after the 1000 diamond plate and then strop lightly to finish off, but for general chopping duties I think 1000 > loaded strop will do it most of the time for me.

Can I just check something though, are you "shaping" the primary bevel because the honing bevel has become too large? One of the advantages of the aggressiveness of diamond sharpening media is that you can ditch the primary/secondary bevel thing if you wanted to and just hone a single bevel (flat or convex as per your preference). You can do this with any sharpening system of course but it's particularly fast on diamonds.

My coarsest water stone marked at 600 doesn't seem as abrasive as my 1000 rated diamond?

Waterstones are known as fast cutters, but diamond is fast. Because the grit on diamond plates is so hard it abrades steel much faster than most of the opposition so comparisons of cutting speed aren't useful if you're more interested in the scratch pattern, which controls the smoothness of the cutting edge.

The Axminster Rider diamond stone that I am considering is double sided at 300/1000 and considered as coarse and fine.

Might I ask, why are you thinking of getting this when you have so much sharpening gear already? Is it a 'the grass is always greener' thing?

 

[ED65]

But particle size isn't the only thing that matters; uniformity of grit size is very important, since the cutting rate is controlled by the average particle size, but the scratches are determined by the largest particles. Shape-sharpness of particles obviously matters too.

Just to add a little more here, one additional point on what makes different things work differently is related to the final sentence.

The friability of the sharpening media is an important factor in both cutting speed and scratch pattern. Waterstones cut fast not because their abrasive particles are harder but because fresh (and hence sharp) grit is exposed as the stone surface breaks down. On any stone that wears more slowly the grit that has become separated from the surface gets a chance to break up and/or round over, which can give more of a polishing action than the nominal grit size would indicate.

 

[Honest John]

Thank you to all whom have contributed to my education on this subject. Little did I know what a can of worms I opened! Sorry if we have gone over familiar ground, but I was concerned about going the wrong way so to speak when changing from diamond to my water stones. The Trend diamond plate I have is one of those "seconds" that Trend sold off very cheaply about 6 months ago. It is clear to me now why they sold hem off so cheaply as mine is bald in places now and one side has become detached from the plastic centre. I would have have been very unhappy if I had played the rrp. The Axminster plate I was considering is a solid piece of steel, so this at least would not happen. My water stones cut fast, but the diamonds are faster. My water stones leave a nice polished surface but are dirty and messy. Thanks again to all contributors.