I know this has been asked before, but doing my research on this site I haven’t gotten a clear answer. Is it possible to sharpen a convex edge on an Edge Pro? Do convex edges usually have any sort of microbevel? The only convex I have is a Mora, but I would really like to learn more about this style of edge. Any information or tips would be great!
-
The BladeForums.com 2024 Traditional Knife is ready to order! See this thread for details: https://www.bladeforums.com/threads/bladeforums-2024-traditional-knife.2003187/
Price is $300 ea (shipped within CONUS). If you live outside the US, I will contact you after your order for extra shipping charges.
Order here: https://www.bladeforums.com/help/2024-traditional/ - Order as many as you like, we have plenty.
Convex Edge Maintenance
- Thread starter BK14
- Start date
So do you need to sharpen the whole bevel to sharpen? I have gotten good results with the Sharpmaker, but was I just applying a microbevel where there shouldn’t be one?
- Joined
- Aug 26, 2011
- Messages
- 250
If you build a curved arm (stone holder) for Edge Pro then yes it’s possible. But keep in mind that the higher point of the arm should be always up. I believe is easier learn freehand.
Sounds like the popular approach is sand paper on a soft backing.
It's possible to do it, but if a convex edge is what you're after, now would be a good time to consider sharpening by hand on some quality bench stones and if you don't use one already, a quality strop and compounds.
On the edge pro, you'll want to start by determining the angle of your primary grind and then setting your guide angle 1 or 2 degrees greater. When you're satisfied you've ground your first incremental bevel, set your guide 1 or 2 degrees greater , and repeat.
Instead of single angle bevel like what you expect from a guided system you're going to try to hone 3 or 4 microbevels each with an increased angle. Your final bevel should be no greater than 20 degrees per side IMO.
Then strop to polish and clean any remaining burr. The stropping should blend the transitions from each of your 3 or 4 micro bevels and give you a nice convexed edge.
On the edge pro, you'll want to start by determining the angle of your primary grind and then setting your guide angle 1 or 2 degrees greater. When you're satisfied you've ground your first incremental bevel, set your guide 1 or 2 degrees greater , and repeat.
Instead of single angle bevel like what you expect from a guided system you're going to try to hone 3 or 4 microbevels each with an increased angle. Your final bevel should be no greater than 20 degrees per side IMO.
Then strop to polish and clean any remaining burr. The stropping should blend the transitions from each of your 3 or 4 micro bevels and give you a nice convexed edge.
Good advice, thanks! All my sharpening money is tied up in the Edge Pro right now, but I think I may try some sandpaper and see how far I get! If I totally mess up the Mora, I’m only out a few bucks.
- Joined
- Aug 26, 2011
- Messages
- 250
Yes. But I believe is possible do it on flat bench stone, or even on a used concave one.
This is what I was taking about, or something like that:
https://www.bladeforums.com/threads/convex-edges-and-the-wicked-edge.1406699/#post-16216963
I freehand sharpen my convex edges on a flat stone. It's not really difficult, you just have to blend everything together until you have a convex bevel.
You can put a micro-convex bevel by stropping at a higher angle. Not a fan of putting a micro-V bevel like you would with a sharpemaker. But I doubt you would notice any difference in performance doing that as long as it really stays microscopic. At some point you will need to reprofile it to a full convex anyways.
Sandpaper with soft backing works fine, but it is easier to mess up and put a really steep angle if you don't know what you're doing. Deburring on sandpaper is also very difficult, making stropping afterwards pretty much mandatory (not so with stones).
Try out different methods and see what you like.
You can put a micro-convex bevel by stropping at a higher angle. Not a fan of putting a micro-V bevel like you would with a sharpemaker. But I doubt you would notice any difference in performance doing that as long as it really stays microscopic. At some point you will need to reprofile it to a full convex anyways.
Sandpaper with soft backing works fine, but it is easier to mess up and put a really steep angle if you don't know what you're doing. Deburring on sandpaper is also very difficult, making stropping afterwards pretty much mandatory (not so with stones).
Try out different methods and see what you like.
Thanks guys, I actually took my Edge Pro stones and used them freehand. Didn’t get the polish that I get when they’re mounted but I’m super happy with the sharpness! My next woodworking project will be to make a stone holder for the stones so I can use them easier in this way.
- Joined
- Aug 26, 2011
- Messages
- 250
This another video showing a sharpening system working convex edge:
The video above shows how the sharpening tool EdgePal Chef sharpens a convex edge in 27 degree total edge with 3,5 degree convex sphere.
The convex edge are made by a angled/bended guide rod that guide the sharpener to make a controled curved movement across the edge, the exact same controled movement in every stroke.
The angled/bended guide rod are a now a 15 years old innovation by EdgePal/Thomas Lofvenmark and it gives a true convex edge in wanted edge angle and wanted convex sphere. The edge can later be maintained in exact the same angle and convex sphere.
The result is a perfect convex sphere in wanted degrees and a perfect cutting edge in wanted degrees - that can be repeated. That means that the edge will not change. Every maintainence sharpening is a continuing of the first sharpening that was made. This minimaze the material taken away from the edge during sharpening.
All EdgePal sharpening tools can grind and sharpen both flat and convex edges sins more then 15 years back in time. It is a EdgePal standard.
Our sharpening tool AxePal sharpens both flat edges on carpenter axes and convex edges on Forest axes. AxePal was inovated and constructed 2002 by EdgePal/Thomas Lofvenmark.
It is possible to sharpen, and maintain, a convex edge with a Lansky sharpening tool. Just bend the small part of the guide rod that are in 90 degree 10 degrees more - then fasten the Lansky in a vice and meassure the sharpener convexing movement with a Angle Cube
Private persons can free copy and use EdgePals bended/angled guide rods. It will not violate our Copyright.
The convex edge are made by a angled/bended guide rod that guide the sharpener to make a controled curved movement across the edge, the exact same controled movement in every stroke.
The angled/bended guide rod are a now a 15 years old innovation by EdgePal/Thomas Lofvenmark and it gives a true convex edge in wanted edge angle and wanted convex sphere. The edge can later be maintained in exact the same angle and convex sphere.
The result is a perfect convex sphere in wanted degrees and a perfect cutting edge in wanted degrees - that can be repeated. That means that the edge will not change. Every maintainence sharpening is a continuing of the first sharpening that was made. This minimaze the material taken away from the edge during sharpening.
All EdgePal sharpening tools can grind and sharpen both flat and convex edges sins more then 15 years back in time. It is a EdgePal standard.
Our sharpening tool AxePal sharpens both flat edges on carpenter axes and convex edges on Forest axes. AxePal was inovated and constructed 2002 by EdgePal/Thomas Lofvenmark.
It is possible to sharpen, and maintain, a convex edge with a Lansky sharpening tool. Just bend the small part of the guide rod that are in 90 degree 10 degrees more - then fasten the Lansky in a vice and meassure the sharpener convexing movement with a Angle Cube
Private persons can free copy and use EdgePals bended/angled guide rods. It will not violate our Copyright.
- Joined
- Jun 29, 1999
- Messages
- 9,730
I maintain my convex edges on a flat bench stone -- just hone backwards (edge trailing).
On maintaining the angle: do you just pick an angle, and then use that edge-trailing wrist rocking motion that I've seen Murray Carter demonstrate?
Also, how does this work if you have a blade with a deep belly curve?
- Joined
- Aug 26, 2011
- Messages
- 250
The video above shows how the sharpening tool EdgePal Chef sharpens a convex edge in 27 degree total edge with 3,5 degree convex sphere.
The convex edge are made by a angled/bended guide rod that guide the sharpener to make a controled curved movement across the edge, the exact same controled movement in every stroke.
The angled/bended guide rod are a now a 15 years old innovation by EdgePal/Thomas Lofvenmark and it gives a true convex edge in wanted edge angle and wanted convex sphere. The edge can later be maintained in exact the same angle and convex sphere.
The result is a perfect convex sphere in wanted degrees and a perfect cutting edge in wanted degrees - that can be repeated. That means that the edge will not change. Every maintainence sharpening is a continuing of the first sharpening that was made. This minimaze the material taken away from the edge during sharpening.
All EdgePal sharpening tools can grind and sharpen both flat and convex edges sins more then 15 years back in time. It is a EdgePal standard.
Our sharpening tool AxePal sharpens both flat edges on carpenter axes and convex edges on Forest axes. AxePal was inovated and constructed 2002 by EdgePal/Thomas Lofvenmark.
It is possible to sharpen, and maintain, a convex edge with a Lansky sharpening tool. Just bend the small part of the guide rod that are in 90 degree 10 degrees more - then fasten the Lansky in a vice and meassure the sharpener convexing movement with a Angle Cube
Private persons can free copy and use EdgePals bended/angled guide rods. It will not violate our Copyright.
I'm sorry if I broke any rules, I did not mean to. Just wanted to show how it works to make a convex bevel using a sharpener. Kudos for the idea.
I do not think that you have broke any rules Brasiliero. I hope that I have not broke any rules when I explain one of the functions on my sharpening tool Chef.
When sharpening by freehand, the human hand wobble. This becouse we have a lot of joints in our hands and arms, 17 joints in each arm and hand, 34 joints total, are involved in the sharpening process - and that makes it impossible to hold a constant angle - and impossible to make the same repeated rockring movement sharpening a convex edge. The result will be that flat edges will be convex - and that a convex edge will be more and more convex - untill a point where the edge angle will be so steep that the edge no longer works - and the edge needs ro be regrinded back to its starting point.
How long time this will take differs, it demands on how much the knife are used and how many times it have been sharpened. Some people will never see this happend, for others, this is a big problem.
For the human hand it is impossble to go below 3 degree wobble during free hand sharpening. This do not means that an flat edge will be convex the first time it have been freehand sharpened - but the convexing process starts there - and after 100 times of free hand sharpening - the former flat edge will be convex.
How many degrees do your convex edge hold on its cutting edge? In my experiance, you do not know. You do not know how many degrees your convex sphere holds either.... In the same time, the blade geomatry and edge profile decides the knifes performance... Convex is not only convex. Fallknivens knifes holds a 6 degree convex sphere - Bark River knifes holds a 2-3 degrees convex sphere. Two very different edge profiles - and performance.
When I construct my sharpening tools I first set up goals. My first sharpening tools name was "Edge" and my goal was that Edge shall be able to grind and sharpen both flat and convex edges, and that Edge shall be able to change edges in degrees. After three years experimenting and after hundreds of prototypes I reach those goals, inclouding the bended guide rod. This was the first tecnical solution that sharpen convex edges with full control of the convex sphere and with wanted degrees on the cutting edge.
i am 71 years old, retired and a privet person, not a company. My hobby is to construct sharpening tools and to solve sharpening problems. I make my tools by hand, all pieces. I mount them together, calibrate them and control them - and deliver them to my customers. I have no stock, I make my tools when they are ordered. I dont markering my tools, I use only my homepage - and happy customers recomendations.
My tools are made i massive aluminum and brass. No plastic. Chef was the first sharpening tool with a real true built in protractor, the first tool that could be adjusted for blade width, the first tool with a fixed distance between the pivot point and the cutting edge (allways 28 cm), the first tool that use stopcollars (and springs) to lock the distance the sharpener can move, and so on. In the same time, my tools are very easy to work with. No tools are needed to handle my tools, just your fingertips.
I have work with, and sharpen, knifes and all other edged tools for more then 60 years and I live big parts of my life without electricity = I sharpen my edged tools by freehand for 40 years and I could se what happend and how they changed during time. My experiance from this made me construct a sharpening tool that solved those problems.
When sharpening by freehand, the human hand wobble. This becouse we have a lot of joints in our hands and arms, 17 joints in each arm and hand, 34 joints total, are involved in the sharpening process - and that makes it impossible to hold a constant angle - and impossible to make the same repeated rockring movement sharpening a convex edge. The result will be that flat edges will be convex - and that a convex edge will be more and more convex - untill a point where the edge angle will be so steep that the edge no longer works - and the edge needs ro be regrinded back to its starting point.
How long time this will take differs, it demands on how much the knife are used and how many times it have been sharpened. Some people will never see this happend, for others, this is a big problem.
For the human hand it is impossble to go below 3 degree wobble during free hand sharpening. This do not means that an flat edge will be convex the first time it have been freehand sharpened - but the convexing process starts there - and after 100 times of free hand sharpening - the former flat edge will be convex.
How many degrees do your convex edge hold on its cutting edge? In my experiance, you do not know. You do not know how many degrees your convex sphere holds either.... In the same time, the blade geomatry and edge profile decides the knifes performance... Convex is not only convex. Fallknivens knifes holds a 6 degree convex sphere - Bark River knifes holds a 2-3 degrees convex sphere. Two very different edge profiles - and performance.
When I construct my sharpening tools I first set up goals. My first sharpening tools name was "Edge" and my goal was that Edge shall be able to grind and sharpen both flat and convex edges, and that Edge shall be able to change edges in degrees. After three years experimenting and after hundreds of prototypes I reach those goals, inclouding the bended guide rod. This was the first tecnical solution that sharpen convex edges with full control of the convex sphere and with wanted degrees on the cutting edge.
i am 71 years old, retired and a privet person, not a company. My hobby is to construct sharpening tools and to solve sharpening problems. I make my tools by hand, all pieces. I mount them together, calibrate them and control them - and deliver them to my customers. I have no stock, I make my tools when they are ordered. I dont markering my tools, I use only my homepage - and happy customers recomendations.
My tools are made i massive aluminum and brass. No plastic. Chef was the first sharpening tool with a real true built in protractor, the first tool that could be adjusted for blade width, the first tool with a fixed distance between the pivot point and the cutting edge (allways 28 cm), the first tool that use stopcollars (and springs) to lock the distance the sharpener can move, and so on. In the same time, my tools are very easy to work with. No tools are needed to handle my tools, just your fingertips.
I have work with, and sharpen, knifes and all other edged tools for more then 60 years and I live big parts of my life without electricity = I sharpen my edged tools by freehand for 40 years and I could se what happend and how they changed during time. My experiance from this made me construct a sharpening tool that solved those problems.
- Joined
- Jun 17, 2013
- Messages
- 1,024
In my very limited knowledge and experience, if you are referring to a 'zero" convex grind, similar to Bark River fixed blades then there is usually no micro-bevel. It is possible t add a convex micro-bevel to any grind (I may be wrong but I think Chris Reeve knives have a convex micro-bevel on a hollow ground blade). Anyway, either a convex ground micro-bevel or zero ground full convex are easy to regularly maintain with a strop and compound and with practice can be reprofiled and maintained on stones. I don't have a guided system but am intrigued by the convex/curved rod offered by KME for their system.
- Joined
- Jun 4, 2010
- Messages
- 6,642
The best way to maintain it is to hit the area right behind the apex - use a Sharpie and instead of making a line along the edge, mark them up radially from edge to spine. Grind behind the edge so when you elevate the spine it takes no more than a few passes to hit the apex.
This is also how you avoid making the apex more broad over time - every sharpening you concentrate behind the actual edge. Over time if you aren't careful you might even make the entire edge more acute.
If you put this sort of knife on a clamp or other widget with an angle guide and mark it up radially, you can determine very accurately what the start and stop values are. The value between can have some variation in the shape of the arc, but you can at least verify the start/stop values.