Thread: A couple of grit/grade questions...

The chart I have from the Sandpaper man says 2000 grit W&D is the same as a Norton 4000 stone (doesn't say which type). Both listed as 6 micron.

I can't see anything wrong with a rougher primary bevel, but others may disagree.

This chart was posted by Chris Schwarz last year http://blog.lostartpress.com/2014/09...arpening-gear/

https://lostartpress.files.wordpress...ory-050514.pdf

Thanks folks.

Yep, it looks like I'm going from 2000 grit (whatever crud B/M sells) at around 10 microns to a King #6000 waterstone at 2 micron which might go some way to explaining the matte look...I'm just not spending enough time on it. I'm still getting burrs and nice sharp edges on the #6000, but not a mirror finish on the backs of these plane blades when stepping up from 2000 grit.

I'll keep fiddling purely for aesthetic reasons coz I'm a bit of a Mynah bird...."OOOHH SHINY!!!"

I have always found the same when I swap between W&D paper and waterstones.

2000 and 2500 paper and I'm getting a mirror but with waterstones I need to go much higher in the grits to get the same look.

It may have to do with the amount of abrasives available.

Paper only has a fixed amount and it quickly crushes up to a finer abrasive so you initially get a quick cut with scratches, then as you keep working it the abrasives get finer with more of a mirrored look.

With the stones, you are crushing the abrasives but fresh grit is just beneath it constantly being refreshed.

I usually let the slurry thicken up a little on the stones towards the end of that grit and I end up with a better look..

But it's all theory! Can't really test it. Saying it feels like it cuts better is not very helpful to anyone!

Just my 2c worth and it's what I came up with years ago to stop me thinking about it!

That's sort of a strange chart, and at the risk of repeating something someone else here said - the sandpaper is going to do some burnishing and some cutting unless it's dead fresh. The waterstone is probably going to have fresh particles on the surface at all times. Two different types of cuts.

There are at least two different conventions used here for 2000 grit paper, and one is fine and the other one not so much (one is about 10 microns, which is almost as coarse as a lot of 1000 stones, the other is finer than most 8000 grit waterstones, or about as fine).

The chart can be misleading unless you're comparing the same type of grit and binder. For example, a translucent arkansas will do a better job finishing a razor than a shapton 15k (but the trans is listed at 6+ microns on there and the shapton is less than 1). the abrasives work differently with varying levels of pressure.

Lee Valley shows a nice chart of the grit particle sizes (in microns) for their offerings of 3M Wet& Dry sandpapers.
Those numbers represent the "nominal" particle size. The implication is that there are some smaller and some larger grit particles.
That logic applies to most abrasives. Statistically speaking: the Mean +/- the Standard Deviation (s)
At the same time, some formulations may be more uniform (very small s), some less so (large s.)

For shine and for the difference between "sharp" and "carving sharp", I need a final treatment with CrOx/AlOx honing compound.
The surfaces are so finely scratched that the metal looks shiny. A simple 10X magnifier will show you what your eyes can't see.
All kinds of grit grade numbers are bandied about, honing compounds in general are 0.25 - 0.5 micron nominal.

Originally Posted by Robson Valley

Lee Valley shows a nice chart of the grit particle sizes (in microns) for their offerings of 3M Wet& Dry sandpapers.
Those numbers represent the "nominal" particle size. The implication is that there are some smaller and some larger grit particles.
That logic applies to most abrasives. Statistically speaking: the Mean +/- the Standard Deviation (s)
At the same time, some formulations may be more uniform (very small s), some less so (large s.)

For shine and for the difference between "sharp" and "carving sharp", I need a final treatment with CrOx/AlOx honing compound.
The surfaces are so finely scratched that the metal looks shiny. A simple 10X magnifier will show you what your eyes can't see.
All kinds of grit grade numbers are bandied about, honing compounds in general are 0.25 - 0.5 micron nominal.

Most of the compounds that come in stick form contain fairly variable aluminum oxide, including iron oxide compounds and chromium oxide compounds. The green stick that LV and many others sell is mostly aluminum oxide and fractionally chrome ox. I think it probably does better at imparting a bright polish than it would do if it was just 100% of those particles.

This came up as a big debate on a shaving forum where people are nutty about particles, and someone asked formax (the maker of the compound) and found that the compound itself could contain al-ox particles up to 6 microns in size. If you examine something done up by that "microfine" honing compound, you will find stray scratches here and there, and they are probably made easier to see by the bright polish the rest of the compound leaves. But the result is *really sharp*.

The nominal 1/2 micron rating is a good indicator of the perceived sharpness, despite the odd cornrow left from a stray large particle.

The only way to get compounds that don't have al ox in them is to look for spec of the compounds that are only what they say they are. I'd suspect the al-ox is in the chrome ox compounds because pure 0.5 micron chrome ox by itself just doesn't polish that fast by hand - if it has any significant amount of work to do.

The micron size given by stones is read literally by a lot of people, but there are so many other factors that it's hard to do anything other than just state what a stone does based on its performance characteristics.

I have used pure oxide pigment powders for shaving, that's the only reason I know any of the above. Otherwise, I'd be perfectly satisfied with the very keen edge that comes from the microfine compound.

I will say this about pure compounds, which you probably already know (as in compounds not bound in wax), the pigment vividness from chrome ox and iron oxide is so strong that if even 1% of a wax stick was made of either of them, it would probably still have a vivid color.

I've gotten other large sticks of compound from mcmaster just to try them for sharpening (they are very cheap, like $10 for 2 or 5 pounds of bar), but theirs are industrial and they do have a significant amount of large aluminum oxide particles in them - not as fine, but certainly fast cutting. If one wants something very specific, it pays to ask the manufacturers of each thing. But most of the problems we're solving are in our head.