Bevel widening at the tip. How to prevent?
- This topic has 5 replies, 4 voices, and was last updated 09/14/2020 at 8:33 am by
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Jacob, I’m glad you recognize that the appearance of uneven height bevels are sheerly aesthetic. Sharpness is (y)our primary goal, (I hope).
Clamping position and knife steel profile can effect the appearance of the bevel heights. We should always strive to find the best, most efficient clamping positions for sharpening each knife.
The taller bevels you experienced may be due to those knives having thicker steel profiles at the tips. This is an intentional manufacturing characteristic to help lessen the chance of snapping off a thin steel tip with less than careful knife use. The practical explanation of this was your taller tip bevel heights were from the sharpened angles between the knife steel and the sharpening stone faces became shallower, more acute or a lower angle, as the distance between the stone and the steel became closer at the thicker knife tips. The resulting shallower tip angle does in effect enhance the cutting character of these thicker steel knife tips. So even though it’s bad to your aesthetic eye it balances out in practicality.
Most of us who gravitated to the precision allowed with W.E. sharpening share your OCD eye. The truth is you’re probably the only one that notices the uneven tip bevel heights. That is if you didn’t bring attention to it while proudly showing off your sharpening job. Or, maybe the rest of us hypercritical “edge snobs” would notice it, if invited to inspect your knife.
The downside to correcting the taller appearing tips requires removing the excessively tall bevel’s steel. As these knives are reprofiled with higher, wider tip bevel angles, to balance out the aesthetics, the steel is lost. The result is the knife edge and the bevel shoulders are moved lower on the knife to where the knife steel is getting even thicker. This may also decrease the knife’s cutting performance. We can never put steel back so we try to learn to do our best the first time.
This is a good reason to always use a steel sparing wider angle setting when sharpening a knife for the very first time. Then after seeing the results it’s easily re-profiled to a more acute angle with the taller bevels, later when a touch-up is needed. Where as, done in the opposite it’s hard to undo the taller appearing bevels.
I recommend you chalk it up to a learning experience and enjoy using these sharp knives till they require re-sharpening.
I suggest when determining the “sweet spot” clamping position you use a very fine grit stone at a very wide set angle to remove the marker ink. The object is to remove just the marker and not the steel. Using a wide guide rod set angle insures you’re just touching the sharpening stones towards the apex of the knife edge. We’re only looking for a visual indicator showing where the stone is contacting the steel. As the stone angle changes along the length of the knife edge relative to the clamped knife’s position, the appearance of removed marker will be thinner, as it removes ink from the upper or lower portion of the marker ink strip, you applied. Repeated re-application of the marker as the knife is moved slightly helps us zone in on this clamping position. The purpose is to use this guide to an efficient clamping position where the ink is removed as close to evenly across the entire length of the knife edge, as possible.
The knife does not need to be resting on the depth key pins to clamp it securely in the vise jaws. The depth key, IMO, is more importantly used to position the alignment guide in a standard reference position to record the relative position of the clamped knife in the vise jaws. The newer, taller advanced alignment guide, AAG, was devised to broaden the reference points to allow for recording the clamping positions when the knife is larger or clamped while rotating the tip up or tip down, away from horizontal.
By reapplying the marker ink as you move the knife’s clamping position, forward, backward, tip up or tip down, you can zero in on the best sharpening position, “the sweet spot”. Even still, the very first time any knife is sharpened with any of the “fixed angle” sharpening systems, like the Wicked Edge, there is some small amount of steel that is inadvertently removed, usually at the knife edge extreme ends, as the knife is profiled to conform to the fixed angle sharpening system. The idea behind “finding the sweet spot” is to limit this unintentional steel loss by best positioning the knife for this first sharpening that usually does this sharpener style knife conforming, profiling. Another reason for sharpening your knife, the very first time, at a wide steel-sparing set angle. If the clamping position was recorded well, each subsequent touch-ups can be done with the knife in exactly the same clamping position as was found to start with. This limits any subsequent unnecessary steel removal. If the knife is re-profiled with a new clamping position steel may be lost again, to conform it again, to the sharpener.
It takes finding a balancing point between best clamping/sharpening position and aesthetics. If the tip steel profile is physically thicker you may not find one single perfect clamping position to totally avoid the bevel height discrepancies that can result. If it’s so bad you can’t live with the visualized differences, you’re alternative is as “airscapes” suggested, to sharpen the knife in two steps matching an individualized clamping position to each knife portion. Then blend the two independently sharpened portions together, at the end.
Addition 8/23/2020: I failed to recognize the added challenges when clamping and sharpening folding knives. Aspects like thumb studs, unusual or multi-faceted and hollow ground blades, or a ricasso and a lack of a sharpening choil, all present obstacles to finding the “sweet spot”. These characteristics may force additional compromises unseen with a more straight forward knife like a chef’s knife. All these aspects do come into play when sharpening knives the first time.
Take your time while using the marker. Inspect the blade and the entire knife for unintended points of contact. Maybe use the marker on these other possible contact points. Wrapping the knife with blue tape may be helpful to see and prevent these unwanted abrasions. It’s important to take your time and don’t let your enthusiasm rush you. There is no substitute for experience.
Marc
(MarcH's Rack-Its)Thanks much, MarcH. This has all been very informative for this WE tyro. Coincidentally, the first knife I reprofiled with my WEPS was a crude Kephart in 1/8” thick 1095 tool steel. I observed widening of the bevel near the tip. It means is the maker did a good job as it should be reinforced, or thicker, at the tip, as a field knife. Or sheath knife as Horace Kephart called them.
I’ll concern myself with the aesthetics of perfectly even and polished bevels when I graduate to my custom folders. That might be a ways off.
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