Thread: Norton silicon carbide vs Aluminium oxide benchstones

The real advantage of anything other than diamond is that the swarf particles crush and collapse over time to give you a finer and finer grit. Diamond is too hard to do that. It cuts as rough, hard and coarse as the day you bought it.

For your amusement, the grit grading systems in Europe, North America and Japan are different. Do you know which one you are using? Which one is Norton using?

You read like somebody who is confident in their sharpening process. Consistent.
My advice is to pick either one. The synthetic stones are far more consistent than the natural stones.
I need a predictable outcome from the process. I suspect that you do, as well.
I hope that I never need such coarse stones for my carving tools. But, I'll go a rough as it takes to fix a big 75mm gouge.

Thanks for replying RV, I do need a fine finish to my tools, I cannot find any sort of grading for the stones, even the Norton website contains no information, they just have a code such as MB8, may have been one, I'll have to have another look.

Hey,

I bought the stone on Lee Valley's website advertised as 90/600# AlOx. When it arrived it turned out to be a Norton coarse/fine India combo stone.

So, it seems to me that a Norton coarse India (aluminum oxide) stone should be 90#, and should be black.

A Norton fine India stone should be 600# and orange in colour.

Hope that's of some use )

". . . . . as rough as it takes. . . . " Forgive me for quoting myself.

There is a fourth grit-grading system for oil stones. Over some months, I bought two of the unlabelled, house-brand, double sided oil stones from the local hardware store. No idea of source but I can make an educated guess.
I use them when gross changes to the edge of a carving tool are needed.

This is the "RV, Look & Feel" grit grading system: Looked to me like I had coarse and medium grits on one stone and medium and fine on the other. Even Sherlock Holmes would agree.
Next, how does it feel? I pulled out several grades of sand papers (Gator Grit, made in Finland, of all places.) Brushed my finger tips over the stones and the sand papers.
I concluded that I got a stone of maybe 60-80 grit. On the other side, possibly 100-120. The rough side of stone #2 was like the 100-120 grit. The fine side might go 180-220 grit.

There you have it. Totally arbitrary and subjective. Completely unfettered by any hint of scientific accuracy. I suggest that this system is every bit as good as it ever needs to be for synthetic oil stones.

However, for 600+, someone else needs to come up with a system for judging those.

RV your grading system sound similar to mine, I may just bite the bullet and get one, these stones are grey in color, i'll post a pic when i get it, thanks for the replies,

You can have my grit-grading system for free. Guaranteed total guesswork.
That's the beauty of it. Abso-tootley universal and unmeasurable.
Both those oil stones are grey-colored, the different sides just have a different "look & feel" to them. Maybe that's why I thought of the sand paper comparison.

The first time that I stood a big Pfeil 5/35 gouge on its nose in a puddle of oil to joint the entire end (sand grain damage), I was a bit nervous. Next time, I'll curse more and blink less. But I got it done, entirely by hand, _and_ carving sharp to my satisfaction.

One thing to remember about all these stones = if they do reveal the so-called "nominal" particle size, it ain't perfect. There will be some distribution of both smaller and larger particles in the mix. Unlike diamond, you can smash a lot of softer grit in the process so you constantly generate smaller, finer abrasive particle sizes.

When I'm lapping stone slabs, about 3cm thick, after less than 5 minutes, I can't feel the sand = just muddy slop. Hose it off and go again. Might see 3-4 minutes of serious cutting action. Each year, I bring home about 100kg sand.
I use the stone for carving bases. Buzz a 3/8" hole through the stone, chip a big countersink pit on the underside and spin a 1/4" lag bolt up into the carving.
If the install is indoors, I usually glue a sheet of felt to the bottom of the stone, ordinary carpenter's yellow glue is fine.