Bevels and angles.
- This topic has 4 replies, 3 voices, and was last updated 08/11/2018 at 10:29 pm by
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Good afternoon!
Is it possible to have identical angles on both sides (17°) yet one side is visually longer than the other?
Put a Kershaw Link on the clamp (WE 130). Painted both sides. Found my angles. Went with 17°. Painted the other side. Worked it until what I thought was 17°. But gently working the other side too. All paint gone. Nice, uniform scratch patterns. Worked through my grits. Painted both sides and double checking with my cube as I progressed with each grit. Made micro adjustments as I needed. Everything appeared ok. All paint was coming off from heel to tip. Something looked a little off, thought it was lighting
Take the knife and sure enough, one side appeared to be longer than the other. I put it back in the clamp, painted both sides, ensured 17° via cube. Used my 1500 for light passes. All paint “appeared” to be removed using my loupe and microscope. 🤔
Where did I mess up? What is a good strategy to fix it?
Thanks!
William
p.s. Angles aside and some scratch issues, the bevels were shiny and it was the sharpest knife I ever held. My first bandaid was needed. My Wife asked if she should be concerned as I slashed paper all around the house.
Hey William,
First I’d look at the knife to see if I could ascertain it is ground symmetrically. (It isn’t to uncommon to see a knife, especially high end hand ground knives, that aren’t perfectly symmetrically ground.) Next, I would look to determine the knife is clamping and staying centered not leaning for some unexpected reason, under the clamping force. A knife edge leaning towards one side will decrease the bevel angle and result in larger taller bevels on that closer side, despite the guide rod angles being set similarly.
If all that appears good, consider this. Our dominant side hand often can do a better more efficient job with our stone work than our less dominant side. This is sometimes seen as a taller or better polished bevel. Even when counting strokes and trying to keep your efforts even, (left and right side), and balanced this still can unconsciously effect our bevel appearance. I prefer to manage my bevels by inspection and appearance then by keeping stroke counts. I have to consciously keep my bevels even through the amount of effort and stone work I exert because I recognize my dominant side does a far better job. Another thing to consider that can effect our bevel size is our finger position and finger pressure to the stones. This can steer where we’re applying the most force and contact.
To correct for the uneven appearance I’d start by verifying my digital angle cube is zeroed. I re-clamp the knife in precisely the same position. I’d swap my stones side for side and end for end, Just for good measure. (I do this as a regular practice every time I replace them in my stone rack to insure I’m giving them even wear). After verifying my guide rod angles, I’d go back to work with the 400 or 600 grit on the side with the shorter bevel.
I’d concentrate my efforts to the shoulder or lower portion of the shorter bevel. As you work down on the bevel and remove steel the bevel height should enlarge as the shoulder goes lower. Don’t do your stone work exclusively to the one side. We still want to maintain the apex and the keenness of the knife edge. If this doesn’t seem, to help the alternative, is to reduce the bevel height of the taller larger bevel. I’d attempt this focusing my efforts and stone work on the top or knife edge portion of the taller bevel. As steel is removed there the bevel should shorten and even out.
I always finish with alternating, L-R-L-R, stone strokes to insure the bevels apex is precise and keen.
I hope this helps. I feel your frustration not knowing if your doing something wrong or your not understanding something about the WE sharpening technique. Remember whats most important and the bottom line is a sharp good cutting knife. That you have achieved. You are probably the only one who would have noticed the uneven bevels because you are closely scrutinizing your own results.
edit: Organic’s response, below, is short and sweet and to the point.
Marc
(MarcH's Rack-Its)Yes, you can have matching bevel angles without having the bevels be the same width. This happens when the apex is not completely centered. You can easily get the bevels to match by spending extra time sharpening on the side with the smaller bevel until the bevel widths match. I typically check to make sure that the bevels are equal in width when I am on the coarsest stone in my progression.
Edit: Marc replied before I finished my response. His is much more thorough.
Thanks Fellas for your replies! So a little extra love for the short side without neglecting the other. So the extra attention will drop that shoulder?
1 user thanked author for this post.
If the knife is straight and ground centered. The extra attention should drop (lower) the short sided bevel, or shorten the long side.
Marc
(MarcH's Rack-Its)1 user thanked author for this post.
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