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Convex Stones...Legit or Gimmick?

With a 25' radius you are talking about a tenth of a degree per side.
Yeah it’s not much. I think the biggest Takeaway is that the curve that were talking about is actually a design aspect of the razor that the manufacture is factoring in. What you wind up with is a very slightly concave bevel plane as opposed to an implied wedge shape. Now the 6’ radius across the width of the stone provides the contact isolation for offsetting slight variances in terms of minute geometry issues.
 
Yeah it’s not much. I think the biggest Takeaway is that the curve that were talking about is actually a design aspect of the razor that the manufacture is factoring in. What you wind up with is a very slightly concave bevel plane as opposed to an implied wedge shape. Now the 6’ radius across the width of the stone provides the contact isolation for offsetting slight variances in terms of minute geometry issues.
I see the radius across the width of the stone as being the main advantage.
 
I can’t support the idea of catastrophic bevel failure due to a 25’ radial curve...
Not going to happen.
I’ve prepared a number of hones this way. A 5K synthetic, a small Coticule bout, & a Thuringian. Honestly they’re a lot of fun to hone on. But without a dedicated lapping plate they’re very difficult to prepare consistently. That’s probably the only reason I haven’t switch completely over to convex hones. Preparing an entire progression of stones in this manner is definitely demanding no doubt about it.

Not sure where a "catastrophic" failure came from.

My point was, it will be more fragile to the same degree that it is more keen. It is microscopic - both! But if one is going to mentioned as a "pro" the other should certainly be mentioned as a "con" yet it isn't.


I agree with you. Perhaps you misread my post. I would not use a convex stone myself as I don’t see how it will work unless I get a convex prefinisher as well. I am perfectly happy with my flat JNATs. As to the poor schmuch, he can do the “wobble test” and then kill his razor on the bevel setters or send his razor to be sharpened to one of the guys here...
You are absolutely correct. The bevel becomes thinner and the edge doesn’t last on thin bevels. I have honed few. You would be hard pressed to get a decent shaving edge...
Sorry, I simply quoted your post for the sake of keeness that was mentioned.
 
I think Jarrod had mentioned the increased keenness as a slight liability recently in a video he posted. This could be a concern for razors that don’t maintain bevel integrity in general. Perhaps due to an overly acute bevel angle or steel quality. But I would propose that in general convex stones don’t pose any great risks and are fair game for the curious. I mean look, it’s a niche interest for sure and it’s just another aspect within the greater context of razor honing.
 
What you’re seeing here is 1000-2000 grit grinding wheels that they use for setting the bevel. Then they move to two different convex bench stones followed by stropping on red paste on leather.
I've seen those in use in France. Can even go up to 6000. These are the turntable style hones that spin like records. One I saw was used at 6000 (because the 1000 had recently cracked), followed by hand honing on a coticule. A flattened coticule, BTW.
 
This debate will never end.

I am going to go hone a fat wedge on a well dished, concave, old coticule and have a top shelf beverage and think of you all.

More than one way to skin cats guys and it is not always about right and wrong.
 
I’ve been tinkering with convex stones
and had some interesting results. They are sublime when it comes to honing warped blades.

As for the increase in keenness, bevel shape, and in general the effect on the shave I still need to zone in on (I only received my concave lapping plate a couple weeks ago) but initial results are encouraging.

If you are gonna use a convex stone for finishing a razor, that might necessitate the use of convex pre-finishers as well.
The coticules I’ve been using have without much difficulty conformed the bevel to the convexity of the hone though I have not yet tried to test how this would go with black/translucent arks or thuringians.

I'll start out by saying that there's nothing at all wrong with flat hones.
Agreed. Convex stones are just additions to the tool box.
 
I think Jarrod had mentioned the increased keenness as a slight liability recently in a video he posted. This could be a concern for razors that don’t maintain bevel integrity in general. Perhaps due to an overly acute bevel angle or steel quality. But I would propose that in general convex stones don’t pose any great risks and are fair game for the curious. I mean look, it’s a niche interest for sure and it’s just another aspect within the greater context of razor honing.
Yep, I also see that the idea that it was as a way to get less than perfect razors out the door acknowledged as well.
I could care less about what anyone uses, truly.
If people like them, great for them!

I firmly believe it was a practice to get more usable product out the door. NOT to make the razor exponentially better through use, as some would have us believe.

Being somewhat quicker for an Ark is a plus for sure, while not a lot quicker from what I've read, anything would help.
 
I’m really glad to note the calm and curious discussion here.

A handful of years ago when this discussion started, it turned to tribalism.

It felt like I was a child back in Scotland demanding if you are Rangers or Celtics. Wayyyy too serious.
 
I have given it a lot of thought and I have thoughted that I don't want to mess with any non-flat stones or plates or balsa. I will keep everything flat. I have heard the arguments for and I don't really agree with them. I have heard all the arguments against and some are pretty convincing. Mainly I am just not going to mess with it. My edges from flat plane honing are already probably very near the theoretical limit of sharpness for razor steel. I don't see the benefit, for me to switch, only problems. If a razor "needs" a convex hone to hone it, I would rather fix the razor, or toss it. But if someone else wants to jump on the convex bandwagon I say power to him. What you think will improve your honing will probably either improve your honing, or make you believe that you have improved your honing, and either way will make you happier. I think.

Meanwhile I will be perfectly agreeable to an edge shootout against anyone who thinks his convex honed razors are sharper than mine.
 
I’ve been tinkering with convex stones
and had some interesting results. They are sublime when it comes to honing warped blades.

As for the increase in keenness, bevel shape, and in general the effect on the shave I still need to zone in on (I only received my concave lapping plate a couple weeks ago) but initial results are encouraging.



The coticules I’ve been using have without much difficulty conformed the bevel to the convexity of the hone though I have not yet tried to test how this would go with black/translucent arks or thuringians.



Agreed. Convex stones are just additions to the tool box.
My comment was geared more toward a black ark convex stone, as you are using a prefinishing stone with those. The coti is a one man band and it can take it all the way home for some. Unfortunately, the coti edge is not for me...
 

Legion

Moderator Emeritus
IMO it is adding another degree of complexity to a relatively simple concept. If I buy a convex hone I also have to have the tool(s) to keep it that way. Then all my hones have to be the same, and if some wear at different rates...

Flat is easy. Slap it on a Atoma or equivalent. Job done. Using simple tests I can check the flatness of a surface. Not so much the convexity.
 
IMO it is adding another degree of complexity to a relatively simple concept. If I buy a convex hone I also have to have the tool(s) to keep it that way. Then all my hones have to be the same, and if some wear at different rates...

Flat is easy. Slap it on a Atoma or equivalent. Job done. Using simple tests I can check the flatness of a surface. Not so much the convexity.
This speaks to the discussion about what works for the manufacturer vs what’s feasible for the end-user being at odds...
 

Legion

Moderator Emeritus
This speaks to the discussion about what works for the manufacturer vs what’s feasible for the end-user being at odds...
Yes, and if the manufacturer is indeed doing it to compensate for inconsistencies in the razors grind, maybe they should be paying more attention to fixing that problem than messing with hones to work around it.
 
Yes, and if the manufacturer is indeed doing it to compensate for inconsistencies in the razors grind, maybe they should be paying more attention to fixing that problem than messing with hones to work around it.
You are always going to have some degree of waste.
If you could reduce that number, it is pure profit. Those razors are already made.

I had always heard the argument they were difficult to make so only the mfg's used them. If they were already making them, they had a means, so why not make them available to maintain their razors and market them? Too expensive they say.
When was the industrial revolution?
Were they making them one offs? I doubt it. Some degree of consistency would have to be met.
 
So I, as an end-user simply cannot make the determination on how such manufacturers should handle Q/C concerns in a way that’s financially realistic so it’s hard to be an educated critic. There may in fact be options out there but maybe the point that they’re at now has already been determined to be as good as possible given the production demands. Geometric inconsistencies have been known for a very long time with certain companies I’m just not sure why things get heated on such topics. It’s as if these discussions take on a kind of political tone. The idea that there are even two different sides to this topic is an illusion. Regardless of why they’re used convex stones are becoming known and more available. It’s just another option out there. If you look at this from an end-user perspective then the concerns of those considering such a purchase might be how demanding maintaining the shape is. Do I really want to make/purchase a dedicated lapping plate? Do I really want to run out and buy w/d sandpaper a few times a year? How much time will it take to reshape an entire progression of stones? Will this work on my wedge razors (No)? In other words does switching to this system from top to bottom make sense or am I just buying a couple of small pieces for the sake of experimentation and novelty?
There’s no doubt that some of these aspects mentioned are going to keep people lapping on flat media. It’s just a lot easier and perhaps consumes less hone material at least initially.
 
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Yes, and if the manufacturer is indeed doing it to compensate for inconsistencies in the razors grind, maybe they should be paying more attention to fixing that problem than messing with hones to work around it.
As far as being frustrated by the fact that these manufacturing inconsistencies exist I’m with you. It is frustrating whether you’re talking about a $10 goal dollar razor or high end peace. I myself don’t even understand why that razors can’t be made more consistently. I just don’t know how much influence we as and users are ever going to really have on that point. I would actually love to make my own razors but there’s just no way for me to make the investment on that kind of equipment but it would really be fun to make something to our own exacting needs and specifications.
 

Chandu

I Waxed The Badger.
Flat is a relative new thing in sharpening. At least flat as we know it today. I think folks have taken it way too far in many respects. There is no flat. Only degrees of flatness. A convex honing surface seems a good way to overcome any anomolies in the razors edge.

If you think about it a cylindrical stone would work just fine and could be an advantage at different stages of honing. Due to the small contact area, it would cut a bit faster than having the full razor resting on a stone

I don't see that it matters one bit if you finished on a convex stone and didn't use convex in earlier stages. Imagine your razor is not quite flat and the flat stone doesn't hit a small part of it. The finisher will. That little section finished is going to be marginally better than if you used a flat finisher and it stayed untouched (obviously this is an extreme example).

I think there is a lot of over thinking as it comes to razor honing. No barber from the 1800's had all the flat stuff we do today and they got it done and done well. They didn't have diamond paste and micro fiber and lapping film.
 
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