Thread: Convex black translucent ark razor hone

Yeah, that video is, um, I'm not sure...That aside, here is a serious question I have about a convex hone like this (though I've never seen or honed on one): For you guys who advocate honing "in the middle" 1-inch of so of a standard 8x3 hone to ensure that all parts of a possible wonky blade make contact with the hone on a solid x-stroke, does a convex hone not , at least in my theory, have that already baked into the cake, so to speak? I guess what I'm asking, put another way, is does that very subtle dome not act as that middle 1-inch depending on your stroke?

I for one would like to test this theory. Wouldn't it be fun to get a hone like this at a meet-up, pass it around and have experienced honers give their impressions? I guess it's all theory until someone on this forum gets one in their hands and reports.

I have a convex coticule from Jarrod and two stones I have convexed myself - a Shapton 1k and a 2 inch wide coticule, neither stone I previously liked.

The stone from Jarrod is a wide bout and has a very subtle curve. It seems to be more convex across than lengthways. It hones well on a shoulderless blade. Appearing to be faster than similar stones. I have not yet fallen in love with it because some angles don't make sense.

I have been experienting with the other coticule and the Shapton on Gold Dollars. The coticule was a terrible specimen prior to convexing it. It is the softest coticule I own and quite slow. Have never got a great finish from it and believe me I have tried. As a convex stone it cuts much faster and I am now getting lovely finished edges. I can now even set a bevel with it. The main challenge is handling slurry, because the way it moves on the hone is quite different from a flat coticule.

Both this stone and the Shapton handled the Gold Dollars very smoothly. I find I can work around clunky stabilisers without any effort or having to modify. Sharpening a Dovo starts to make more sense as well. The odd overhoning you sometimes see on the heels from the factory is easy to hit and even out.

I'm not a covert to covex hones, but based on my initial experiments I think it could be a way to improve poor performing stones.

So, a similar theory/argument has been going for years with convexing grinding stones to make it easier to grind a chisel or plane iron. Most folks use a straight ground wheel and don’t see where it is an issue or a benefit, just grind it.

A similar discussion about cambering a plane blade so the plane corners do not dig into the work. Folks have devised all manner of jigs and machined concave stones, sold for hundreds of dollars. But for hundreds of years Carpenters and Furniture makers have just done 10 extra laps with a finger pressure on one corner, then the other for a perfect camber, Bud-a bing.

The theory is all razors are warped, and if they are, few are warped enough to matter. The rolling X is designed to allow the heel of the concave side to fall off the stone and allow the middle of the razor to be honed by one inch of the edge of the stone. If they are warped, its not an 1/8 or 1/16, but thousands.

With a domed stone you are honing with an even smaller piece of the stone and the raised portion allows the convexed part of the blade to make contact and the heel and toe clear the stone.

Folks have been shaving regularly for a couple hundred years and no-one ever though to dome a stone, why? Now these were smart guys, who figured all the geometry and design that we still use today.

An elegant solution to a non-existent problem.

Originally Posted by Euclid440

An elegant solution to a non-existent problem.

+1........................

Awesome logic

Use a Convex hone because Dovo does, yet we ALL agree that Dovo Factory edges are sub par Yep makes absolute sense

Maybe if they used flat hones we wouldn't be fixing all the damn frowns in them too Yep convex make tons of sense

Originally Posted by Euclid440

An elegant solution to a non-existent problem.

I think this pretty much sums it up. While there is doubtlessly a logic to the convex stone, it definitely seems like it's asking the tool to step in where technique is what is really called for.

I have bought a few vintage stones that were domed. I can't say whether this was intentional or not. I always flattened them.

For me it's fun playing around with a domed stone. I hone for fun. Trying different Honing techniques, good or bad, adds to the fun. So far I haven't seen an advantage except that it has sped up a poor stone and made it useable. Over all I don't find the domed stone as flexible as a flat one and doubt I could be persuaded from that.

I have some reservations about the Solingen approach to using domed hones for production items.

I used to work for one of the biggest manufacturers in the world in another sector. One colleague of mine designed the processes in our top performing factory . He once said to me that you design the process for success, catch the failures and manage them out by preventing them. You don't design the manufacturing process to incorporate the failures.

It seems to me that, rather than removing warped blades completely, the Solingen manufacturers have come up with a way of Honing them easily within their productivity line. In effect they have adapted their process for the exception, rather than removing the exceptions.

Originally Posted by Euclid440

So, a similar theory/argument has been going for years with convexing grinding stones to make it easier to grind a chisel or plane iron. Most folks use a straight ground wheel and don’t see where it is an issue or a benefit, just grind it.

A similar discussion about cambering a plane blade so the plane corners do not dig into the work. Folks have devised all manner of jigs and machined concave stones, sold for hundreds of dollars. But for hundreds of years Carpenters and Furniture makers have just done 10 extra laps with a finger pressure on one corner, then the other for a perfect camber, Bud-a bing.

The theory is all razors are warped, and if they are, few are warped enough to matter. The rolling X is designed to allow the heel of the concave side to fall off the stone and allow the middle of the razor to be honed by one inch of the edge of the stone. If they are warped, its not an 1/8 or 1/16, but thousands.

Speak for your own straights. I have had some that had more warp than The Enterprise under Kirk chasing after blue and green alien chicks!

I got the stone today and took it out for a test. First, I took my industrial steel ruler and placed it on the stone the length way. The arch was subtle and not pronounced mid width of the stone. I got my water & ballistol 50-50 mix and sprayed a little on the stone. I used a Koraat razor I shaved with yesterday and honed it with 50 laps then 50 more back and forth laps. I watched and the blade remain flat on the stone. I always use a X stroke and had no problems with this. I then shaved with the razor and found the shave to be smoother. I also noticed the sharpness didn't seem compromised. Still extremely sharp, just smoother. The blade is full hollow bellied 7/8. I am still going to compare this stone with my Zulu Grey. I really need more time with this stone but I can see a difference in how the stone mellows the edge. As for using a convex stone for damaged blades only, I see no merit in this. It worked fine on a perfect razor. I'll post pictures in a day or two of the stone.

These convex stones are an interesting topic. I'm still learning to use flat stones, so I'm relying on the KISS method.
I would like to see the process for convexing a trans ark.