Norton India Binder?

The exact formulation of binders is typically a trade secret to some extent, but they're using a common vitrified bond. The bond-to-grit ratio is one of the main determinations of bond strength and so they're just making it a hard bond.
 
Yes, that stone and material is very wear resistant. I wish the SiC stone were that way. DM
 
Blues said:
Ain't it the truth. But then it wouldn't cut as well as it does either. Everything's a compromise.
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Yup. A big reason why Japanese water stones cut so fast is because they're so soft. Can't get a fast-cutting stone without some combination of increasing grit size, softening the bond, increasing the grit protrusion, or changing the grit type.
 
I have more than a few old Norton India stones that were yard sale and flea market specials.

If they are out of flat they can be very tough to get true.
Even with 30 grit silicon carbide powder it can take a while.

They can be worth the trouble though.
A fine India leaves a great edge and I enjoy using them, they have great feel and feedback.
 
I believe it is glass. Through a microscope you can see blue, green and clear bits in the stone that I believe are what hold it together when fired. I've seen the same ones in the SiC stone - is possible the wear rate difference is entirely due to the abrasive busting out and not the binder.
 
Silicon carbide is more friable than aluminum oxide, so that could certainly be a factor. As far as "glass" goes, vitrified/ceramic bonds are glassy bonds. :)
 
That just does not compute in my brain. It has to be soft to cut better.?? It has to have a soft binder to release the grit which causes it to cut better. This wording makes sense to me. Whatever the binder is it works for the India. They are a ceramic.
Norton's India and Spyderco's ceramic express the same characteristics with binders. They are very hard and don't release their
grit. = slow cutting. This helps toward it being a slow wearing stone. A characteristic sharpeners like. But then we Don't like this
characteristic when we have to level it. Ha, Funny. So, true we cannot have both. Yes, the feedback is great. Which I think makes it enjoyable to use. It's best use is for lessor steels (commercial grade cutlery). As I've noticed it starts to struggle when
cutting 440C. Still, one of my favorite stones but it has limits. DM
 
David Martin said:
That just does not compute in my brain. It has to be soft to cut better.?? It has to have a soft binder to release the grit which causes it to cut better. This wording makes sense to me. Whatever the binder is it works for the India. They are a ceramic.
Norton's India and Spyderco's ceramic express the same characteristics with binders. They are very hard and don't release their
grit. = slow cutting. This helps toward it being a slow wearing stone. A characteristic sharpeners like. But then we Don't like this
characteristic when we have to level it. Ha, Funny. So, true we cannot have both. Yes, the feedback is great. Which I think makes it enjoyable to use. It's best use is for lessor steels (commercial grade cutlery). As I've noticed it starts to struggle when
cutting 440C. Still, one of my favorite stones but it has limits. DM
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Nope. Spyderco's ceramic is sintered alumina, which doesn't use binders. A puny amount of a sintering aid may be added to the alumina, but there's not actual binder holding it together. It's essentially like an artificial sedimentary rock. Enormous amounts of heat and pressure are used to compress the grains together so hard that they fuse together. This is why they don't shed grit really at all.

Nortons are a vitrified bond, which is a ceramic, but not the same kind. The abrasive grains are bound together by mixing them with a feldspar clay (the specific composition of which is typically a trade secret, and may be altered for different applications) and the hardness is the result of a combination of the pressure used in molding the stone, bond composition, and grit/bond ratio. During firing the clay binder forms a glass-like structure that holds the grains together.
 
I wondered if you'd let me get by with saying that. I notice more of the red clay stain when I clean my 1970's Norton India stone. Than the new, hecho en Mexico stone. DM
 
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The Norton India stones made in NY and those made in Mexico (a more recent stone) act and feel different when using them.
It's like they changed material between the two time frames.
willc, to level mine, I use a 120 grit stone or my 80 grit SiC stone with water. This will level it in about an hour perhaps a little more of rubbing. Once finished I may not have to level it again for 20 years, or more, depending on the amount of sharpening. DM
 
The grit is probably sourced from a different manufacturer, and so has slightly different qualities, and the grit/bond ratio, specific binder composition, and press rate may also be slightly different. In fact, trying to have one manufacturer clone another's is nearly impossible. You can shoot for the same performance qualities, but you won't outright clone it.
 
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