Billyfergie
Forum GOD!
Aye..The Same Concave Hone Guff is Getting Arrogantly Flouted as Troll Threads on the TSD Forum..No Dummies Ere..
Billy
Sharpness vs Keenness as Described by an Old Solingen Grinder
- Thread starter thesuperiorshave
- Start date
Aye..The Same Concave Hone Guff is Getting Arrogantly Flouted as Troll Threads on the TSD Forum..No Dummies Ere..
Billy
Let me just start by saying that i just hone my own razors, and i have no other motives than to discuss the subject of using convex hones.
When someone is telling me i have a problem, you are doing it wrong, this is the best way to do it, my initial reaction was defensive. My edges was shaving me just fine. Sometimes i needed to tone them down a little. It will off course not be easy to convince me with this starting point (and i am a stubborn bastard to
). It would have been much easier for me if i was also educated about some of the down sides of using a convex stone, and about where the point of diminishing return was with this approach relative to using a flat stone.
The only way i felt i could say something about the subject was to try it in practice, and by making the theory make sense to me.
I convexed three stones to a wheel radius of around 1.5 m in both axis. This is a small radius, which is pushing the boundaries a little. I set the bevel with the first stone, using an angled approach to the stone. This changes the effective bevel angle to an more shallow angle and the height of the bevel increases (more on the affect of this later), because you are able to change the contact point of the apex relative to the spine contact point, see illustration. You do not have to do this, but this was just to see how far i could take this. The simplest thing would be to try and approach it more perpendicular.
The downside can be; If you are not aware of aware of this, and if you use your normal x-strokes, you can end up with an uneven apex and bevel, because the bevel angle will be changing during the stroke. If your bevel angle is already at 16-17 degrees, the steel may not be able to support this geometry. By approaching the stone more perpendicular you will be getting more or less the same angle as if you hone on a flat stone.
Given that you decide to play with the bevel angle the possible gain can be quite significant. The cutting efficiency of an more shallow angle is one benefit. An added benefit is that the edge becomes more flexible. If you think of the bevel as a cantilever beam it is not a linear relationship between the length of the bevel and the flexibility. When you look at the deflection, the length is raised to the power of three. A small change will have a big impact, even without taking into account the minor hollow ground effect you get depending on the radius you use.
The I (moment of inertia) value in the denominator is the determined/effected by the the thickness of the bevel at the cross section you consider. Even a tiny reduction here can make a difference in both the angle (from the middle of the bevel to the apex) and the flexibility of the bevel.
In my short experiment, using a 6/8 full hollow ground razor, the effect was noticeable. I must add that this particular blade had a bent spine, which makes it a good candidate for using a convex stone. I did end my progression with a jnat that was more ore less flat. It had a little crown shape.
In my head this is what i ended up with. Someone else might want to finish with a convex stone.
So where does the diminishing return come in? The shaving efficiency is determined by the angle of the bevel plane, the thickness at the apex and the thickness/width a few microns behind the apex (if you for the sake of argument disregard the condition of the apex).
In my case if i stayed to long on my finisher i will probably giving away some of the gains if the secondary bevel is allowed to grow.
If you have a razor that has an angle, say around 16-17 degrees, and the geometry of the razor is even enough to enable you to make contact on a flat surface, and if this razor is honed using flat stones, ending with a good finisher, the added benefit may not be worth it (this is only my opinion).
I smiling blade will also throw in allot of variables i am not willing to deal with.
On the other hand if this same razor has been honed multiple times using tape on the spine (bevel angle is now above 18 deg), you may want to want to manipulate the angle and shape a little, without grinding down the spine. There is multiple reason you may want to preserve the spine.
A convex stone might be something worth while in this case.
If you have a razor with a bent spine, to the extent that you are not able to make contact with a flat stone (even a narrow one) on the concave side of the blade, a convex stone will enable you to make contact and hone it in a simpler manner. Other problematic geometry issues might also be simpler to handle on a convex stone.
If you are honing your first razor, one of the most common problems are applying to much pressure. I know i have been guilty of this.
I find this to be a delicate thing to control even now. By working on a much smaller contact point controlling the pressure is even more difficult on a convex hone. A full hollow ground razor will flex a little, and thus help you to some degree to avoid some of the liabilities this gives. Heavier grinds and stiffer blades might be even more difficult.
One thing i did notice was when i used my convex coticule stone i was able to hone even when it got "sticky". The razor is not sucked to the stone the same way. I believe i can then get a little extra out of that particular stone.
How to create and maintain these stones is a different subject. I did not need a concave shaping plate to shape my stones, but they would be really nice to have for maintaining the stones, if you decide to go this way.
So to me it is not flat vs convex, i want both for different situations. Everyone needs to make an informed decision, but i think the subject needs to be discussed on it's own merits, without any personal biased or finical perceived motives.
This can still be a good approach and the tool someone is promoting should be welcomed as an innovation.
This is not my first language, so if you try to read between the lines, somethings might be lost in translation
When someone is telling me i have a problem, you are doing it wrong, this is the best way to do it, my initial reaction was defensive. My edges was shaving me just fine. Sometimes i needed to tone them down a little. It will off course not be easy to convince me with this starting point (and i am a stubborn bastard to
). It would have been much easier for me if i was also educated about some of the down sides of using a convex stone, and about where the point of diminishing return was with this approach relative to using a flat stone.The only way i felt i could say something about the subject was to try it in practice, and by making the theory make sense to me.
I convexed three stones to a wheel radius of around 1.5 m in both axis. This is a small radius, which is pushing the boundaries a little. I set the bevel with the first stone, using an angled approach to the stone. This changes the effective bevel angle to an more shallow angle and the height of the bevel increases (more on the affect of this later), because you are able to change the contact point of the apex relative to the spine contact point, see illustration. You do not have to do this, but this was just to see how far i could take this. The simplest thing would be to try and approach it more perpendicular.
The downside can be; If you are not aware of aware of this, and if you use your normal x-strokes, you can end up with an uneven apex and bevel, because the bevel angle will be changing during the stroke. If your bevel angle is already at 16-17 degrees, the steel may not be able to support this geometry. By approaching the stone more perpendicular you will be getting more or less the same angle as if you hone on a flat stone.
Given that you decide to play with the bevel angle the possible gain can be quite significant. The cutting efficiency of an more shallow angle is one benefit. An added benefit is that the edge becomes more flexible. If you think of the bevel as a cantilever beam it is not a linear relationship between the length of the bevel and the flexibility. When you look at the deflection, the length is raised to the power of three. A small change will have a big impact, even without taking into account the minor hollow ground effect you get depending on the radius you use.
The I (moment of inertia) value in the denominator is the determined/effected by the the thickness of the bevel at the cross section you consider. Even a tiny reduction here can make a difference in both the angle (from the middle of the bevel to the apex) and the flexibility of the bevel.
In my short experiment, using a 6/8 full hollow ground razor, the effect was noticeable. I must add that this particular blade had a bent spine, which makes it a good candidate for using a convex stone. I did end my progression with a jnat that was more ore less flat. It had a little crown shape.
In my head this is what i ended up with. Someone else might want to finish with a convex stone.
So where does the diminishing return come in? The shaving efficiency is determined by the angle of the bevel plane, the thickness at the apex and the thickness/width a few microns behind the apex (if you for the sake of argument disregard the condition of the apex).
In my case if i stayed to long on my finisher i will probably giving away some of the gains if the secondary bevel is allowed to grow.
If you have a razor that has an angle, say around 16-17 degrees, and the geometry of the razor is even enough to enable you to make contact on a flat surface, and if this razor is honed using flat stones, ending with a good finisher, the added benefit may not be worth it (this is only my opinion).
I smiling blade will also throw in allot of variables i am not willing to deal with.
On the other hand if this same razor has been honed multiple times using tape on the spine (bevel angle is now above 18 deg), you may want to want to manipulate the angle and shape a little, without grinding down the spine. There is multiple reason you may want to preserve the spine.
A convex stone might be something worth while in this case.
If you have a razor with a bent spine, to the extent that you are not able to make contact with a flat stone (even a narrow one) on the concave side of the blade, a convex stone will enable you to make contact and hone it in a simpler manner. Other problematic geometry issues might also be simpler to handle on a convex stone.
If you are honing your first razor, one of the most common problems are applying to much pressure. I know i have been guilty of this.
I find this to be a delicate thing to control even now. By working on a much smaller contact point controlling the pressure is even more difficult on a convex hone. A full hollow ground razor will flex a little, and thus help you to some degree to avoid some of the liabilities this gives. Heavier grinds and stiffer blades might be even more difficult.
One thing i did notice was when i used my convex coticule stone i was able to hone even when it got "sticky". The razor is not sucked to the stone the same way. I believe i can then get a little extra out of that particular stone.
How to create and maintain these stones is a different subject. I did not need a concave shaping plate to shape my stones, but they would be really nice to have for maintaining the stones, if you decide to go this way.
So to me it is not flat vs convex, i want both for different situations. Everyone needs to make an informed decision, but i think the subject needs to be discussed on it's own merits, without any personal biased or finical perceived motives.
This can still be a good approach and the tool someone is promoting should be welcomed as an innovation.
This is not my first language, so if you try to read between the lines, somethings might be lost in translation
Last edited:
Here is an example of Heljestrand mk 4, honed on a convex Naniwa 3k, following it with tomo slurry on a dead flat jnat.Let me just start by saying that i just hone my own razors, and i have no other motives than to discuss the subject of using convex hones.
When someone is telling me i have a problem, you are doing it wrong, this is the best way to do it, my initial reaction was defensive. My edges was shaving me just fine. Sometimes i needed to tone them down a little. It will off course not be easy to convince me with this starting point (and i am a stubborn bastard to
The only way i felt i could say something about the subject was to try it in practice, and by making the theory make sense to me.
I convexed three stones to a wheel radius of around 1.5 m in both axis. This is a small radius, which is pushing the boundaries a little. I set the bevel with the first stone, using an angled approach to the stone. This changes the effective bevel angle to an more shallow angle and the height of the bevel increases (more on the affect of this later), because you are able to change the contact point of the apex relative to the spine contact point, see illustration. You do not have to do this, but this was just to see how far i could take this. The simplest thing would be to try and approach it more perpendicular.
The downside can be; If you are not aware of aware of this, and if you use your normal x-strokes, you can end up with an uneven apex and bevel, because the bevel angle will be changing during the stroke. If your bevel angle is already at 16-17 degrees, the steel may not be able to support this geometry. By approaching the stone more perpendicular you will be getting more or less the same angle as if you hone on a flat stone.
View attachment 99848
Given that you decide to play with the bevel angle the possible gain can be quite significant. The cutting efficiency of an more shallow angle is one benefit. An added benefit is that the edge becomes more flexible. If you think of the bevel as a cantilever beam it is not a linear relationship between the length of the bevel and the flexibility. When you look at the deflection, the length is raised to the power of three. A small change will have a big impact, even without taking into account the minor hollow ground effect you get depending on the radius you use.
View attachment 99850View attachment 99851View attachment 99852
The I (moment of inertia) value in the denominator is the determined/effected by the the thickness of the bevel at the cross section you consider. Even a tiny reduction here can make a difference in both the angle (from the middle of the bevel to the apex) and the flexibility of the bevel.
In my short experiment, using a 6/8 full hollow ground razor, the effect was noticeable. I must add that this particular blade had a bent spine, which makes it a good candidate for using a convex stone. I did end my progression with a jnat that was more ore less flat. It had a little crown shape.
In my head this is what i ended up with. Someone else might want to finish with a convex stone.
View attachment 99855
So where does the diminishing return come in? The shaving efficiency is determined by the angle of the bevel plane, the thickness at the apex and the thickness/width a few microns behind the apex (if you for the sake of argument disregard the condition of the apex).
In my case if i stayed to long on my finisher i will probably giving away some of the gains if the secondary bevel is allowed to grow.
If you have a razor that has an angle, say around 16-17 degrees, and the geometry of the razor is even enough to enable you to make contact on a flat surface, and if this razor is honed using flat stones, ending with a good finisher, the added benefit may not be worth it (this is only my opinion).
I smiling blade will also throw in allot of variables i am not willing to deal with.
On the other hand if this same razor has been honed multiple times using tape on the spine (bevel angle is now above 18 deg), you may want to want to manipulate the angle and shape a little, without grinding down the spine. There is multiple reason you may want to preserve the spine.
A convex stone might be something worth while in this case.
If you have a razor with a bent spine, to the extent that you are not able to make contact with a flat stone (even a narrow one) on the concave side of the blade, a convex stone will enable you to make contact and hone it in a simpler manner. Other problematic geometry issues might also be simpler to handle on a convex stone.
If you are honing your first razor, one of the most common problems are applying to much pressure. I know i have been guilty of this.
I find this to be a delicate thing to control even now. By working on a much smaller contact point controlling the pressure is even more difficult on a convex hone. A full hollow ground razor will flex a little, and thus help you to some degree to avoid some of the liabilities this gives. Heavier grinds and stiffer blades might be even more difficult.
One thing i did notice was when i used my convex coticule stone i was able to hone even when it got "sticky". The razor is not sucked to the stone the same way. I believe i can then get a little extra out of that particular stone.
How to create and maintain these stones is a different subject. I did not need a concave shaping plate to shape my stones, but they would be really nice to have for maintaining the stones, if you decide to go this way.
So to me it is not flat vs convex, i want both for different situations. Everyone needs to make an informed decision, but i think the subject needs to be discussed on it's own merits, without any personal biased or finical perceived motives.
This can still be a good approach and the tool someone is promoting should be welcomed as an innovation.
This is not my first language, so if you try to read between the lines, somethings might be lost in translation
No tape was used.
Twelvefret
Forum GOD!
I’ve never understood why honing to shave provokes such drama.
I honed my first straight razor and shaved. Some old razors are better than others. Some SR users have more skill than others. Some beard hair is more coarse than others. Some men like to hone.
For me, what we should be doing is making using an SR as easy and less difficult as possible.
Watch the video of the person both making and using a SR. Then adopt the parts your prefer and forget the rest.
I honed my first straight razor and shaved. Some old razors are better than others. Some SR users have more skill than others. Some beard hair is more coarse than others. Some men like to hone.
For me, what we should be doing is making using an SR as easy and less difficult as possible.
Watch the video of the person both making and using a SR. Then adopt the parts your prefer and forget the rest.
JamieM
Extreme sharpness is ephemeral!
No drama, I hone hundreds of razors every year, it's an acquired skill that most practical-minded people can and do master, the last thing you want to do is start bringing up drawings and numerical equations that make it look like something you need a degree in geometry and mathematics to do, honing it's really simple you need a stone and a razor and lots of practice.
That is a bold statement on behalf of many SR users. I am sorry you feel this way. Thanks for your time.
That is true. In principle you only need a few stones and some skill. With your knowlege you can really be a montor.
This is about learning a skill, and having some fun doing it.
Twelvefret
Forum GOD!
I figure if I can get the same ATG /WTG shaving my whole face with a SR as I can using a Feather Shavette, I’m not doing it all wrong.
And for the record, I have not honed that many razors. Nothing compared to Steve and Jamie .
And for the record, I have not honed that many razors. Nothing compared to Steve and Jamie .
If you read my first post you will see that there is probably not much to gain for you with this starting point.
Make it simple. If i only had my coticule i would be a happie camper.
When you buy a new razor with a bent spine and try to hone the concave side, it is not fun any more. This is a typical problem if you buy one of the lower end models. It is not simple. If you get a desent blade it us usually quite simple for most people.
UKRob
Forum GOD!
When you buy a new razor with a bent spine the first thing to do is return it to the supplier for replacement. Trying to hone it will probably result in the seller refusing a refund. That is the message you should be trying to get across.
If you are asked to hone a razor with a bent spine you can always use a rolling action to ensure all parts of the bevel get attention - that’s where the experience, that @JamieM is referring to, comes in to play.
Your photograph of the Heljestrand above - what stone would you have used as a finisher if the spine was bent?
Zwilling
Kamisori shaver
If experienced honers want to test this theory, more power to them. I am a casual honer, I enjoy the process of preparing and maintaining my own razors. Sometimes I surprise myself, sometimes I disappoint myself. All part of a primitive but beautiful way of shaving that I enjoy - I suppose all of us do.
I think that all in all, no good will come of this thread because of the forceful way in which the OP posted his convictions. He was also somewhat evasive in answering queries, and touchy - if straight razor shaving was all people with that attitude, I’d probably never have persevered. I like the locals here, and the reaction in this thread says something about the ATG crowd. There is lots of expertise here but it’s also inclusive.
I think that all in all, no good will come of this thread because of the forceful way in which the OP posted his convictions. He was also somewhat evasive in answering queries, and touchy - if straight razor shaving was all people with that attitude, I’d probably never have persevered. I like the locals here, and the reaction in this thread says something about the ATG crowd. There is lots of expertise here but it’s also inclusive.