edge pro/wicked edge question

HeavyHanded · Sep 1, 2015

This is more for the edgepro, but a general question re guided sharpeners that are influenced by changes in the width of the blade. Eg a bolo pattern, Nessmuk, or similar. How does one maintain the same edge angle from tip to heel, or is it going to shift somewhat as the width of the blade shifts?

I apologize for asking, am certain this has been covered but I couldn't come up with a way to phrase the question that gave me a solid hit.

Twindog · Sep 1, 2015

As you move up the belly to the tip, the angle becomes more acute. You can minimize that effect by clamping closer to the tip.

Personally, I like an edge that becomes more acute near the tip, which is where I do more fine work that doesn't need as robust an edge as the other parts of the blade.

If you use an Angle Cube so something like it, you can see the effect.

On the EdgePro, but not the Wicked Edge, a distal taper can (depending on how you hold it) change the sharpening angle, too.

Chris "Anagarika" · Sep 1, 2015

I remember Lagrangian made a thread about this sometime back.
A very complicated analysis for my mind

Found it: www.bladeforums.com/forums/showthread.php/1131476-Geometry-and-Kinematics-of-Guided-Rod-Sharpeners

Not sure if it's helpful, but I'm guessing not possible without keep moving the clamped parts. Your free hand would yield a much more consistent result :thumbup:

REK Knives · Sep 1, 2015

Martin,

Here is a video I made that shows on a PM2 how to get a perfectly evenly degreed edge from heel to tip on the WEPS. That being said, it is only because of the gentle sweeping arc of the blade I sharpened. If you had a straight flat portion of the edge then the angle would indeed change, although it's minute I believe. What most don't understand is how to manipulate the knife in the vise. You can't be just locked in to mounting front to back, you also have to be willing to tilt up and down to get the angles you want.

For example: If I took that PM2 in the video below, and tilted it EXTREMELY down, what would happen? The tip would become more steeper of an angle. The same applies to a more conventional blade shape... So if you purposely want a knife, such as a USMC kabar, go to a steeper degree near the tip, you will have to mount closer to the tip and tilt the tip downward. This is actually advantageous compared to the Edge Pro as I don't have to change any settings to do this. It help if you want a tougher tip or for purely aesthetic reasons.

Hope this helps.

[video=youtube;2T0wQDHKMR0]https://www.youtube.com/watch?v=2T0wQDHKMR0[/video]

HeavyHanded · Sep 2, 2015

Thanks to all, more or less confirmed what I had assumed but better to get it from folks that know. The Lagrangian thread especially helpful.

The system I'm working on has the angle of the grinding surface fixed, the knife has a fixed point the spine rests on and can pivot either around this point, or up and down to maintain contact with the abrasive. So my issue is the opposite of an EP - the greater the width of the blade, the more acute it will be relative to the more narrow spots. Am not seeing a notable difference in bevel width, so probably is the range of a degree or two at most.

Acadian · Sep 2, 2015

razor-edge-knives said:
Martin,

Here is a video I made that shows on a PM2 how to get a perfectly evenly degreed edge from heel to tip on the WEPS. That being said, it is only because of the gentle sweeping arc of the blade I sharpened. If you had a straight flat portion of the edge then the angle would indeed change, although it's minute I believe. What most don't understand is how to manipulate the knife in the vise. You can't be just locked in to mounting front to back, you also have to be willing to tilt up and down to get the angles you want.

For example: If I took that PM2 in the video below, and tilted it EXTREMELY down, what would happen? The tip would become more steeper of an angle. The same applies to a more conventional blade shape... So if you purposely want a knife, such as a USMC kabar, go to a steeper degree near the tip, you will have to mount closer to the tip and tilt the tip downward. This is actually advantageous compared to the Edge Pro as I don't have to change any settings to do this. It help if you want a tougher tip or for purely aesthetic reasons.

Hope this helps.

[video=youtube;2T0wQDHKMR0]https://www.youtube.com/watch?v=2T0wQDHKMR0[/video]

I watched this video when you first posted it and it really helped me figure out how to angle my knives on my Wicked Edge. Well done!

BTW that's a Tenacious I believe and not a PM2

Thanks Josh!

FW JSB · Sep 2, 2015

razor-edge-knives said:
Martin,

Here is a video I made that shows on a PM2 how to get a perfectly evenly degreed edge from heel to tip on the WEPS. That being said, it is only because of the gentle sweeping arc of the blade I sharpened. If you had a straight flat portion of the edge then the angle would indeed change, although it's minute I believe. What most don't understand is how to manipulate the knife in the vise. You can't be just locked in to mounting front to back, you also have to be willing to tilt up and down to get the angles you want.

For example: If I took that PM2 in the video below, and tilted it EXTREMELY down, what would happen? The tip would become more steeper of an angle. The same applies to a more conventional blade shape... So if you purposely want a knife, such as a USMC kabar, go to a steeper degree near the tip, you will have to mount closer to the tip and tilt the tip downward. This is actually advantageous compared to the Edge Pro as I don't have to change any settings to do this. It help if you want a tougher tip or for purely aesthetic reasons.

Hope this helps.

[video=youtube;2T0wQDHKMR0]https://www.youtube.com/watch?v=2T0wQDHKMR0[/video]

So, what you do in your video with tilting the blade the using the tape and marker will also help to get an even width bevel along the entire edge of the blade? Using a Sebenza as an example, one thing that drives me nuts is that due to the tip getting thicker towards the tip, as it sweeps towards the spine, I always end up with a bevel that is wider at the tip than at the heel. It's a purely aesthetic issue, but it still bugs me. Great vid and thanks for any additional info.

REK Knives · Sep 2, 2015

Acadian said:
I watched this video when you first posted it and it really helped me figure out how to angle my knives on my Wicked Edge. Well done!

BTW that's a Tenacious I believe and not a PM2

Thanks Josh!

Ahhh good catch! Been a while since I filmed that lol. And glad I could help!

FW JSB said:
So, what you do in your video with tilting the blade the using the tape and marker will also help to get an even width bevel along the entire edge of the blade? Using a Sebenza as an example, one thing that drives me nuts is that due to the tip getting thicker towards the tip, as it sweeps towards the spine, I always end up with a bevel that is wider at the tip than at the heel. It's a purely aesthetic issue, but it still bugs me. Great vid and thanks for any additional info.

Yes and no... That question is kind of involved.

If you use this method w/ a blade that has a perfect primary grind then yes, you can get a perfect width edge bevel from heel to tip. However, if your primary grind is off or it gets thicker at the tip (like your sebenza probably is) then you will either have to have the primary grind re-done OR you can use a combination of tilting and mounting as far forward as possible. What this will do is actually make your edge bevel go to a steeper degree towards the tip which will make the side width of the edge appear close or the same, however, if you took a caliper to the shoulders of the edge then you would find that the tip is in fact much thicker and won't cut as well due to the increase in angle degrees.

Hope that helps and sorry for derailing your thread Martin!