Thread: GRIT!

maybe a dumb queston , but i have a few old barber hones id like to know the grit of wondering i there is a way to figure out the grit of a stone would i maybe need a micro scope?

That is a tough question, looking at a stone really isn't the way to test grit, honing with it puts your razors at risk, but you can get a basic idea if you have enough hones to compare to, or you can look at the scratch pattern it leaves on your edge. None of these is a definitive way to discover the grit, but it might get you in the ball park.

Maybe someone else can provide better help than I can.

Well, I got nothing better than what Mike said - compare and contrast with other hones of known grit is what I do when I want to know the grit of a new stone.

But, maybe your barber hones are known and used brands by some of the members here. Photos, or just their names if they have any, posted here could get you some results.

James.

I don't have the luxury of your problem, but here's what I would try to do:
Cut as many pieces of the same soft metal as you have hones.
Put on a scratch pattern with each hone on each one of them.
Make sure you have at least one "known grit" hone.
Make digital pictures of the samples with a USB microscope, or a regular stereo-microscope, with a picture tube. (Maybe you'd have to send your samples to a member with the right equipment for that.
Open the pictures in a program like Photoshop, that has the capability to place a ruler next to your picture, and count the grit marks for 1/10" or so. Compare the count results to the ones of the known sample, and calculate the grit of you hones.

I'm only making this up on the spot, but I see no reason why this couldn't work. Of course you would need to be careful to use the same magnification and digital resolution for all samples.

Best regards,
Bart.

Grit is one of those things that we get hung up on needlessly sometimes. The coarseness or fineness of a particular hone's grit is only part of the equation. Other factors include the shape of the grit particles (are they fairly smooth and rounded, or are they sharp and jagged?) and the hardness of the material the grits are embedded in.

Less jagged particles leave a smoother edge than their grit size might indicate. That's why a coticule performs like a higher grit hone than a Norton 8K, even though the particle size is similar.

A hard matrix leaves less of the individual grits exposed to cut, so the hone acts like a finer grit. That's how some guys can use a 2K Arkansas natural hone as a finishing hone.

Most barber hones seem to be in the medium or fine category, between 6K and 10K. They were touch-up hones, and most were manufactured with the idea that you would shave off them without any further refining of the edge.

You really have to try each one and see how the edge performs. One of my barber hones produces an edge that seems duller than a Norton 8K edge, but it is more comfortable to shave with.

Barber hones were made by many manufacturers, and the quality seems pretty varied. As much as we'd like to help, the best approach is probably experimentation.

Josh

Originally Posted by JoshEarl

Grit is one of those things that we get hung up on needlessly sometimes. The coarseness or fineness of a particular hone's grit is only part of the equation. Other factors include the shape of the grit particles (are they fairly smooth and rounded, or are they sharp and jagged?) and the hardness of the material the grits are embedded in.

Less jagged particles leave a smoother edge than their grit size might indicate. That's why a coticule performs like a higher grit hone than a Norton 8K, even though the particle size is similar.

A hard matrix leaves less of the individual grits exposed to cut, so the hone acts like a finer grit. That's how some guys can use a 2K Arkansas natural hone as a finishing hone.

Most barber hones seem to be in the medium or fine category, between 6K and 10K. They were touch-up hones, and most were manufactured with the idea that you would shave off them without any further refining of the edge.

You really have to try each one and see how the edge performs. One of my barber hones produces an edge that seems duller than a Norton 8K edge, but it is more comfortable to shave with.

Barber hones were made by many manufacturers, and the quality seems pretty varied. As much as we'd like to help, the best approach is probably experimentation.

Josh

Thanks! you just answered a million questions for me!

To actually measure the grit (particle size) one would need to take a sample of the hone and remove the matrix medium. Then one would have to use one or more of a number of methods to test the physical size of the remaining particles. A liquid suspension test might be the most appropriate, this is what they use to determine the particle size in clays and other fine materials.

This being said, the proposed "try it on a blade and compare" solution might seem a lot more viable. What Josh said is very true for abrasives in general.

Even then you have difficulties. Most hones don't just have one size grit, it's a range of sizes. I think the Japanese grit measuring system measures the smallest, the US the largest and EU the mean. Or something like that.

And to make life just that bit easier, it appears the Japanese Industrial Scale (JIS) of grit measurement tops out at 8k.

James.

After a few years you can assess the grit by rubbing your wet finger over the hone. Don't feel like it'll be a mystery forever.