Thread: Yet, another Black Surgical question

I don't doubt that the arkansas stones are harder than the chinese, but I don't think a safety pin would put a scratch in either one of them. Are you sure that the line on the translucent isn't just the metal from the safety pin? It looks awfully dark to be a scratch.

Originally Posted by crazycliff200843

I don't doubt that the arkansas stones are harder than the chinese, but I don't think a safety pin would put a scratch in either one of them. Are you sure that the line on the translucent isn't just the metal from the safety pin? It looks awfully dark to be a scratch.

Good thought, crazycliff. I just got the translucent Arkansas stone out again, dark lines still on it, and was able to rub them off with my finger. Underneath both dark lines were faint white ones, which polished off with a cloth. I think the white lines were actual scratches, but just barely visible. The dark lines were metal, as you thought. The white lines on the Chinese stone are scratches. So, what is the "real" hardness of novaculite? It probably depends on the mineral outcropping where it was quarried, like Belgian coticules. I am guessing that my Black Arkansas might be greater than 16000 grit, since a Shapton was unable to raise a slurry on it. Diamond is the hardest substance on Earth!

Here's a Arkansas Stone Grade Table. The specific gravities seem interesting. I have a black and a pink translucent, both are slipstones. I always had the impression that the pink translucent is a bit finer than the surgical black. It's a close call though.

Very cool site!
What a variety they have! Even big ones.

That they go by density instead of grit is something new to me but does make sense.


Hardness for Novaculite is unavailable,
but for Quarz it is 7
whereas Korund is 9 and
Diamond is 10

What I have learned from this interesting thread is that I have been thinking of grit and hardness of a hone interchangeably, when actually they are not at all the same thing. A fine grit hone will polish a razor edge well. A very hard hone will do so also, although possibly much more slowly. Novaculite is extremely hard, with a MOH hardness of 7. (just looked it up in a chemical company reference manual). That means that a surgical Black Arkansas hone has the same hardness as if it was made out of solid garnet. Wow! Unfortunately, it is a slow polisher and does not really remove metal at all, in my experience. I just honed a razor that was not passing the HHT on my black Arkansas, until it would pass the HHT off the hone.I t took about 200 passes. I then stropped it 50 on linen and 50 on leather. Tomorrow, I plan to shave with it and see if the edge is appreciably better than usual for that razor.

As far as novaculite is concerned, I think the hardness is related to the grit. The harder the stone, the higher the grit. As all arkansas stones are made of the same material, the density is the big difference between them. That's probably why you couldn't find a definitive value for the hardness.

Originally Posted by Croaker

What I have learned from this interesting thread is that I have been thinking of grit and hardness of a hone interchangeably, when actually they are not at all the same thing. A fine grit hone will polish a razor edge well. A very hard hone will do so also, although possibly much more slowly. Novaculite is extremely hard, with a MOH hardness of 7. (just looked it up in a chemical company reference manual). That means that a surgical Black Arkansas hone has the same hardness as if it was made out of solid garnet. Wow! Unfortunately, it is a slow polisher and does not really remove metal at all, in my experience. I just honed a razor that was not passing the HHT on my black Arkansas, until it would pass the HHT off the hone.I t took about 200 passes. I then stropped it 50 on linen and 50 on leather. Tomorrow, I plan to shave with it and see if the edge is appreciably better than usual for that razor.

Hey Croaker, thanks for this info. Thanks much to the rest of you fine people. I was actually worried that this post would result in series of potential flame replies just because it has been asked before in previous posts (searched).

Croaker, let me know for sure either PM or better yet, re-post here. If you get good results, then I wonder if I can just get the Belgium Coti (to go with my Belgium beer!), and a slurry stone, then finalize on the black, then linen, then strop. Or would hitting the black be overkill? Dunno. I am stoked though.

Thanks,

Alpsman

I have an Arkansas Translucent and all I can say, which has already been said, is that it is way slow. Somewhat unpredictable as well. I don't know if it's going to take 50 strokes or 100 or 150 to get the polish and result I need on a given razor. I put about 50 razors to the test on this a few years ago and started off with just 10 strokes. Silly me. Don't try to lap one of these with any kind of diamond product.......

Have fun,

Lynn

I kind of like the white translucent (as will be evident from earlier posts) - 50 to 75 laps after a thuringian seemed to do it most times for me. I have had experience of the black as well, and IMHO the white translucent is a finer stone. What Lynn says about not honing these on a diamond plate is right - it really took the life out of my DMT 325 and left it more like a 600!

Regards,
Neil

Alpsman wrote:
> I just want to stay ahead on edge maintenance on a newly honed DOVO, not create a new bevel. Can I use this stone with confidence (although slow), then linen, then leather to "touch up" the razor once a month or two?

Yes; that should work just fine. That's what I do. :-)

It's probably because of my inexperience with razor honing and years of using them for knives in general, but I sort of like the slowness of Arkansas stones. They seem to protect better against the occasional error in technique than the faster cutters do.

Yes - you guys aren't kidding about lapping them with diamond plates - I smoothed out a coarse diamond sharpener prettly handily doing that also.

Lynn - Do synthetic stones show more consistent numbers of honing strokes across various razors/steels than the Arkansas stones? That's really interesting; I wonder why that is so? Because of their faster cutting action?

Thanks,
Jeff