Thread: Grit sizes

When we say 4K/8K Norton, what grit size scale does that refer to? And are Shaptons measured with the same scale?

There's a European, USA and Japanes grit size scale.

I'm not sure that the 4k/8k even refers to a specific grit size. It is some kind of mysterious scale. Is there an expert in the house?

Duh, reminds me to work on that table.

Norton 4000 = F800 or JIS(new) 2000
Norton 8000 = F1200 or JIS(new) 4000

I think of it as the ankle bone is connected to the shin bone, the shin bone connected to the knee bone, the knee bone connected to the thigh bone and so on. The analogy being start with the 1k to the 4k to the 8k and on up the ladder. Whatever they really are it is coarse to fine in practical application.

I do not believe I have ever seen a grit equivalency chart that I can believe. So Good Luck Olivia!

All manufacturing has tolerances- what are those per manufacturer?

8000 grit, whatever that means, will not be the same, even if they used equivalent sizes as one manufacturer may believe that 8000 grit should denote the smallest particle in the mix, while company B believes it should denote the largest.

Just buy natural stones, then you'll never have to worry about the grit sizes.

Actually the FEPA standard says that 75% of the particles are of that size.
The remaining 25% can be smaller or bigger.

Originally Posted by 0livia

Actually the FEPA standard says that 75% of the particles are of that size.
The remaining 25% can be smaller or bigger.

Hee hee;( I was speaking hypothetically; internationally so. Even with this standard there is plenty of room to make one stone a "better polisher"

Originally Posted by 0livia

Duh, reminds me to work on that table.

Norton 4000 = F800 or JIS(new) 2000
Norton 8000 = F1200 or JIS(new) 4000

So that's Norton, how about Shapton, made in Japan? Do they use a different (i.e. Japanese) scale?

The reason I am asking is that most of us will do a grit progression when setting a bevel and progress to polishing an edge. We simply look at numbers and automatically presume that a higher number means a finer hone which would be OK if all manufacturers of synthetic hones use the same grit scale.

Shapton uses another kind of grit measuring type,
called the "Mesh-Size".
The Mesh Size is referred to on the back of the Glasstones,
right next to the actual grit size in micron,
unfortunately without any tolerances.

The Mesh-System is actually referring to a Wire-Mesh,
and theoretically the number indicates the density of a wiremesh that was used
to sort the grits out, in respect to the actual wire diameter

I guess things got a little out of hand
because wiremeshes could be used for sorting standart sandpaper grit sizes
but were nowadays commonly used for diamond pastes
wich came to be widely availiable.
But who could possibly think about a wire mesh designed to sieve out 0.5µm particles

The Mesh grit system is somewhat more reliable when it comes to higher grit sizes,
because Jis System stops at 8.000, everything beyond it is not covered by the system
(wich doesn´t mean it don´t exist)
The thing is, there seem to be many interpretations of the mesh system as well *sigh*
Maybe they all refer to different wire diameters (d'uh)

0.5µm is ofte times referred to as 50.000 Mesh,
sometimes it´s 60.000
and Shapton says it´s 30.000 ....
btw. Shapton 16k would translate into JIS 14k, I guess

I think we will have to get used to the fact that we will never be sure
if one hone is actually finer grained than the other.
But that is not a big deal, because even though we would now it
it wouldn´t asure a better finish, keener edge, smoother shave

So what I do is, I rely on the numbers as little as possible.
I know that my Shapton 5.000 comes before my Naniwa 8.000
for example.
But I am open minded when it comes to
Shapton 5k or BBW first?
Naniwa 10k or Shapton 16k first, or maybe after the Chinese 12k?
So when it comes to finishing I refer to feeling more than numbers.
If a Naniwa 10k gives me a better shave on a certain razor
than the Shapton 16k did, I am perfectly fine with that,
even though numbers would indicate different.
It´s a lot trial and error

But you should not let yourself get confused.
A finisher is a finisher. Even though in my example above the Naniwa 10k
provided me a better shave than the Shapton 16k,
that doesn´t mean you have to go and buy both!

You cannot rely on the numbers given by the factory
if you want to compare hones with other brands.
But you can certainly rely on them as "relative progression scales".
So you will most of the time definitely know a Naniwa SS 8k comes after a SS 5k,
but maybe not before a King 8k, for example.