Thread: If you could only buy one...

Originally Posted by DaveW

The novaculite particles in a fine oilstone are fairly large, like 6 microns large. They are aggressive cutters in slurry or when the surface is fresh, but because they are soft, they can become dull or worn fairly quickly.

The stones that have novaculite are usually hard enough to hold the abrasive in place so that will happen. If they are not hard enough to do that, then they will never cut that fine. But hard arkansas stones and the charnleys I've used will definitely hold their particles on the surface and become worn, especially at the pressures you hone a razor.

When an abrasive is fairly dull, you get a polished surface on the steel because it is not cutting deep, or much at all. Tim Zowada's pictures of what an arkansas stone will do without slurry are instructive, I think they might be linked in the library/wiki here.

As far as I know, there are no natural particle sizes that are comparable to the submicron powders that we use (diamonds, chromium oxide, etc), so the natural abrasives have to be held in place and allowed to be burnished so that they in turn burnish or polish steel. Otherwise, they will be too large to achieve a nice super sharp finish. Light pressure on the dulled surface cuts or polishes slowly (thus the patience comment), but leaves a nice finish if you work it up to maximum potential.

thanks so much for all this great information! I've learned quite a bit from your posts and now have two stainless steel blades that are now finally shave ready. and I don't hate them anymore ,lol.

Dave

I have a Cretan hone that is a novaculite
http://www.coticule.be/the-cafeteria/message/26869.html

and is a very hard stone. Cuts great on slurry or water and polishes so well on water. thanks again

This is my Cretan:
http://i171.photobucket.com/albums/u...cretanhone.jpg

Does your Cretan have some fissure cracks on the honing surface? Mine has one and I remember reading somewhere that Emmanuel said that they won't effect honing, just wanted to see what your opinion is. I agree that the cretan does a fantastic job at setting a bevel on slurry and polishes quite well on plain water.

Originally Posted by Milkylee

Does your Cretan have some fissure cracks on the honing surface? Mine has one and I remember reading somewhere that Emmanuel said that they won't effect honing, just wanted to see what your opinion is. I agree that the cretan does a fantastic job at setting a bevel on slurry and polishes quite well on plain water.

No, mine is a continuous smooth surface. and yes it sets a bevel, cuts fast with slurry and polishes very well on water. Interesting effects also if one uses different grit slurry stones as well.Does a fantastic job on my Japanese chef knives which has a very high carbon content. sharpens it in seconds.

I have suche a Stone to i use Mine with Oil
With slurly i think he is aboud 800-2000 Grid and with Oil only it is 9000

My Stone is verry smal only 5" x 2"

Is there any informations aboud bigger thurkish oilstones?

Originally Posted by DaveW

Woodworking, metalworking, polishing, toolmaking, knife enthusiasts....all of these folks seem to have a better grasp on carbides and abrasives. Carbides are pretty much the reason oilstones have fallen out of favor with woodworkers, and even novice woodworkers seem to have a good understanding of why some tool steels are more difficult to sharpen than others. Metalworkers and machinists have a good understanding of them because they've been using high speed steel cutters for a long time, and toolmaker's for the same reason.

Part of the reason there's not a good grasp of it in the razoring world is because most razors seem to be made of mystery steel. Aside from that, I'm not sure why it is not that well understood when the information is freely available and everyone else seems to have a good grasp on it. All of the other hobbyists / trades I mentioned above know exactly what steel they're sharpening when they're choosing an abrasive. Nobody in *any* of them would recommend a natural stone for a razor that was cryogenically treated 440C, even though the cryogenic treatment does make for an improvement in the size and structure of the carbides.

To the point of the original question, if you like to use mostly stainless razors and you match up a stone with soft silica abrasive or novaculite, it shouldn't be a surprise that you have a lot less room for error and a lot more time at the stones to get an edge that will still be inferior to a quick carbon steel edge.

Stop by woodcentral and mention carbides and abrasives, and provide the opinion above, that stainless and carbon steel sharpen to a similar level of sharpness, and see what people say. You will instantly get a response that it is only the case with abrasives harder than the carbides in the stainless steel (though woodworkers more commonly use A2 steel and in some cases high speed steel, the carbides are the same elements).

Thanks for the information. I'm curious to see what you think of the Zulu Grey on stainless steel razors.

Everything you have said about the stainless razors finishing better with diamonds and CBN sprays, is what I have experience so far. That is until I did my stainless steel Dovo on the Zulu grey! Maybe was beginners luck, or I used a finer touch, or the rock has some kind of abrasive that is tougher than the carbides on the stainless, but whatever it was, it gave me one of the smoothes and closer shaves I ever gotten from almost any of the razors (15 total, two stainless) in my rotation (most of them, proffecionally hone). So, when you get it, and work some stainless steel on it, I would like to know what if anything is making my edges better with that stone.

To the original Poster, with my limited knowledge, I would say a finisher (Zulu Grey or 12k Naniwa or 16k Shapton Glass) would be my choice. Because at this stage of my honing experience, I'm learning more up keeping my razors than restoring them from bevel and I'm appreciating the finishers more and more. Double O