Chart for kenjig dimensions

[Jan]

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A useful angle setting method should be robust which means that it should have the ability of tolerating common errors in input parameters. In my understanding the setting should result in angle accuracy of some +/- 0.25⁰. When the desired grinding angle is 15⁰ than the real angle will be between 14.75 and 15.25⁰. Similarly when the desired honing angle is 16.5⁰ than the real angle will be between 16.25 and 16.75⁰. If we consider the least favourable combinations we will hone at an angle which is 1 to 2⁰ higher than the grinding angle. This will probably allow successful deburring.

When the angle setting accuracy drops below +/- 0.5⁰, successful deburring is not guaranteed, because the honing angle increase may be too small.
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This is interesting and I tend to agree with you, only based on my hands on experiences.  It causes me to wonder about the sensitivity of the black marker method of estimating angles, IF one were to carefully study the nuances of where and how much on a bevel that the marker is removed, revealing where the grinding/honing is occurring.  I do not suggest this as a potential substitute for precision angle setting.  Only as a curiosity.  Gradations of where and how much marker is removed certainly reflect differences in angles and granted, may be too gross to be of any practical use.  I'm too busy to spend any time exploring this, just an associated passing thought. 

P.S.: Rick, I am not sure what is your Go Calc app, but assume that it is the Knife Sharpening Angle Calculator coded by CB. I have validated this calculator, it uses the exact formula and works fine. It should provide the same figures as in my charts. I am mentioning it because some apps offered on this forum use the older, approximate Ton formula and are not fully suitable for advanced deburring procedures.

Yes, CB's GoCalc.  I checked it against angles generated in TormekCalc 2 and they were withing 0.02mm, which I regard as irrelevant, primarily since I am not concerned about the exact angle, but rather the relative consistency between wheels and operations.  Using the same app should maintain that consistency.  As I understand it, you (or someone) has validated that TormekCalc2 generates accurate values as well. 

Rick

Rick, I have read somewhere that the thickness of black sharpie line is some 100 millionth of an inch. Red line should be thicker.

Yes, I have validated the TormekCalc2 it generates accurate values. The 0.02 mm discrepance generated by CB's sw is negligible.

Jan

[Jan]

Rick and Jan,

Good comments; thank you. I do not take offense with your comments about the kenjig. The present jig is the most recent of several generations of prototypes. If it remains the most recent generation for several years, we are not doing our jobs. We need to continue evolving.

I based the kenjig on Dutchman's tables. This was well before Wootz' pioneering work on deburring. Jan, your point is well taken. Based on your comment, I think it makes sense to switch kenjigs every five or six millimeters. I make the present kenjigs out of baltic birch plywood, using my table saw and bandsaw. The set up is quick and easy. I usually make up several at a time as gifts. Making separate kenjigs for every five or six millimeters would not be a problem.

I sharpen my own cooking knives. My simple methods are quite adequate. If modifying things can make adequate better, I will choose better.

Ken

Ken, thanks for your understanding. You know that I am large fan and user of kenjigs. The angle accuracy 0.25⁰ is really a very good result and 6 mm loss in diameter is still acceptable switching interval for kenjigs. The accuracy 0.25⁰ is necessary only for advanced deburring methods.

If you are honing freehand, as recently shown in Tormek Live Sharpening Class you of course do not need grinding angle accuracy 0.25⁰. For freehand honing it is fully sufficient to switch to another kenjig each 10 to 12 mm ( ≈ 1/2") loss in stone diameter.

Jan

[RickKrung]

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Rick, I have read somewhere that the thickness of black sharpie line is some 100 millionth of an inch. Red line should be thicker.
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Jan

I think we are talking about different things.  Your comment seems to be about the thickness of the layer of marker, either black or red.  I was speaking about what proportion of the bevel width over which the marker is removed, as a reflection of how closely the grinding angle is to the existing bevel angle.  I was speaking about the width of marker remaining near the heal of the bevel, then the angles would be closely matched.  As opposed to marking being removed from only about half of the bevel width, from the apex towards the center of the bevel width, which would be less well matched.  More extreme would be if only a very small width of maker is removed at the apex, then the angles are not well matched at all. 

My point was, at what level of gradation of this "width of marker removed" could it be discerned as comparing to tenths of an angle of deviation from the intended or desired angle. 

Perhaps this discussion should be carried on in a different post/thread, so as to not hijack the discussion about kenjigs.

Rick

[Jan]

Rick, thanks for your clarification. Your idea "width of marker removed" is very interesting.

I was talking about using marker lines as tiny ink "shims" with a thickness of some 2 or 3 microns.

Jan