Starting Point For Zero Tolerance 0801
- This topic has 5 replies, 4 voices, and was last updated 08/18/2018 at 12:32 am by
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Jayson I can only speak in generalities since I have no personal experience sharpening that particular knife. I’m assuming your use of the term “scale” is to denote the position of the knife, clamped, as it corresponds to the Wicked Edge alignment guide or the advanced alignment guide. I don’t have a clamping position to suggest. I can say that sharpening the knife while maintaining the size of the bevels along the full length of the knife is a result of the knifes position in the vice/jaws and the “sweet spot position”.
If you had previous sharpening results where the bevel towards the tip was wider, that is probably due to the angle the stones made contact with that portion of the knife edge was a shallower or more acute angle than the rest of the bevel. This could be caused if you had not positioned and clamped the knife correctly or the knife tip was rotated up too high and closer to the stones, or the grind of the knife through the tip portion became wider/thicker and closer to the stone.
In general, as the knife is closer to the stone the angle that the stone impacts the knife edge will be lower or shallower, relative to the vertical knife center, (i.e., the rod end connection brackets are closer to the center or vertical line of the knife and the stone is leaning up closer to vertical or 90.0º relative to the zeroed base, or, which is a 0.00º relative rod angle setting or vertical), and the bevel width is wider because the contact area is more as the stone becomes more parallel to the knife’s side, for theses shallower/steeper angles. As the stone is leaning down, at wider angle settings, (when the guide rod end brackets are farther away from the vertical blade center), closer to horizontal, (i.e., 0.00º relative to the base), the bevel gets narrower as less of the stone contacts the knife edge making a narrower contact area, as the stone is more perpendicular to the knife’s blade side.
To raise or widen the angle you achieved, at the tip, on your earlier attempt, (i.e., to make the bevel narrower), I would try to rotate the knife tip down lower and away from the stones, the next time I sharpened that knife. These aspects are all related to the proper knife clamping position and the “sweet spot”.
To determine the “sweet spot” I always recommend to begin with a very wide, obtuse angle, much higher an angle than you want to profile the knife bevels too. (This way any bevel scratches or steel removal, you may cause, while finding the “sweet spot” will be very narrow and shallow and will be removed by your deeper bevel when you sharpen the knife to your profile bevel, angle of choice). Use a very fine stone so as to barely contact the knife edge, to impart very little scratch patterns and cause very little steel removal. With the sharpie ink applied to the bevel and the stone essentially laying over or resting over against the knife edge, with very light pressure applied, you should be able to see the portions of the bevel along the edge, (with lighted magnification), where more ink is being removed due to deeper/more contact, and less link is removed with lighter/less contact.
Use this difference in the appearance of the width of the removed ink to adjust the knife’s clamping position to try to even out the strip of ink left remaining. Remember, less ink is removed when the stone impacts or contacts the edge at a wider angle. More ink is removed as the stone impacts or contacts the edge at a lower angle. By essentially moving the knife down under and away from the stone, or by moving the knife up towards and nearer to the stone, this adjust it’s distance to or from the stone, at the angle the rods are currently locked in at, while you are finding “the sweet spot”. Again, the portions of the bevel with thicker ink remaining are further from the stone’s contact than the portions where more ink was removed and that ink line left is narrower.
After you get the amount of ink removed to appear equal in thickness along the full length of the knife’s bevel, only then would I start adjusting the guide rod angle settings, lower, toward your sharpening goal, to see how the stone impacts the inked knife bevel as you approach your desired sharpening angle. If you again see differences in the amount of ink removed across different areas of the bevel then readjust or fine tune your clamping position, forward, backward, up and down or rotated the tip up or tip down, however it’s necessary to get the width of the ink removal as close to equal across the entire knife’s length of the bevel.
This exercise needs to be done only the first time you determine the best position to sharpen any knife, (i.e., that knife’s “sweet spot”). After you get the knife’s clamping position set, record the “scale” as you call it, the clamping coordinates, in a “sharpening log” for future reference.
Remember the very first time any knife is sharpened with a Wicked Edge Fixed Angle System the knife edge will be profiled somewhat to the characteristics of the fixed angle sharpener. This can be most evident towards the heel and the tip. There is a balance you need to achieve or possibly sacrifice in the edge profile as the knife is sharpened the very first time. This profiling is minimized with the proper placement of the knife blade while sharpening it, (i.e., sweet spot). If you have recorded this sharpening position for future reference the bevel will match precisely for all subsequent sharpenings and touch-ups.
Finding the “sweet spot” and determining the existing bevel angle are separate steps and slightly different. First you determine the “Sweet spot” to determine the clamping position that will allow the most efficient contact between your stones and the entire bevel across the full length of the knife. Once you have determined the “sweet spot” position, now your knife is positioned properly to then determine the existing bevel angle.
After you have determined the “sweet spot” and logged the settings. Next continue with the same clamping position and your sharpie. Now, as you lower the guide rod angle settings slowly, as you remove and reapply the sharpie ink, using lighted magnification, keep inspecting the bevel edge to determine when you have removed the ink as closely across the bevel’s width, down the entire length of the knife, as you can. When it looks like you’ve accomplished this, this is your bevel angle, matched to the knife makers bevel. Record this angle in your log, that you measure using your zeroed angle cube laid flat against your stones as they contact the bevel. You may determine the bevel angles differs from knife side to side and you may find it doesn’t match, everywhere, along the full length of the knife. This is a common issue when sharpening a hand made knife with a fixed angle precision sharpener. Like I wrote in the paragraph above, you may have to find a compromise between the closest angle you can match, to the original maker’s bevel angle, and the best angle you can apply with the WEPS.
Marc
(MarcH's Rack-Its)Sorry, I don’t own that knife so I don’t have any setting to suggest. Even if someone does provide you with their recommended clamping position settings, it will only be a starting point and you will probably have to adjust it to suit your particular knife. Thankfully, Marc practically wrote a book on how to adjust the blade and find the optimal clamping position. Good luck!
Nor do I, but I’d like to add (as I am often compelled to do, or, here’s my two cents worth!) that the width of the bevels is quite dependent on the thickness of the blade where the bevel meets the face grind. It’s not uncommon to find that field-work knives are ground thicker near the tip to reduce the chance of breakage.
This can make the effort to achieve a uniform bevel width more difficult, but the standard process of finding the sweet spot usually solves the problem. You only need to know that thickness is a contributing factor as you try to understand what’s happening. Knives with deep bellies make it easier, while the ZT 801 has a more gentle curve. This means that the bevel angle will be more constant along the edge and therefor less able to correct for changes in thickness.
Of the hundreds of knives I’ve sharpened, I don’t recall ever making a concerted effort to maintain bevel width near the tip. As a personal preference. I like the low bevel angle at the tip (read as a wider bevel face) and a pointed tip as it gives me the option of using it for tasks where precision is a requirement. For instance, cutting a sliver from a finger.
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