Quickly Setting the Angle when using the Knife Jig(s)

[cbwx34]

So here's my take on quickly setting the angle to sharpen a knife, using the standard knife jigs (or also the Small Knife Holder).  This is in beta... and comments/critiques greatly encouraged...  (I know I'm not perfect). 

First, as seen in the Picture 1 (right photo), I establish a mark on the inside of the wheel, where I can line it up with a chopstick attached to the handle, (use what I have lying around, haha).  This becomes a reference mark where I can quickly move the wheel into an exact position each time.  I tried a few other methods, but this was the most precise and fastest for me.

Second, I set up the wheel.  After positioning the wheel on the reference mark,  I used the the AngleMaster, set a blade at 15, 20, and 25 deg. and just mark the wheel at these locations, (left photo) (for the stone turning in both directions).  I also mark the side of the wheel, so as the wheel wears, I can remark the face (or just use the side) as needed.  (Sharpie lasts quite a while, even on the face).  (I was surprised I had to make a set of marks for each direction... more on that later).

Picture 1


Once this is done, as seen in Picture 2, I can now clamp a knife in the jig however I want, or use the Small Knife Holder... (the length doesn't matter).  Once clamped, I simply rotate the wheel to the reference mark, lay the clamped knife between the wheel and Universal Support, then slide the Universal Support in/out to line the edge up with the line at whatever angle I want to sharpen at.

Picture 2


Anyway, so far, so good.  I tried several knives, and after a little practice, was able to quickly hit the angle I want, and also "rehit" an angle, without issue.  Checking with the AngleMaster occasionally since then... it's shown to be pretty accurate.


But, here's the question I have.  There is a big difference in distance between the markings sharpening edge trailing vs. edge leading (stone turning away from or into the blade), as seen in this photo...

Picture 3


... I remarked the stone in a different area, and went to 30 deg., just to show a bit better.  (The side view just shows how I mark the side of the stone, making remarking the face as needed easier, or just use the side as the guide).

My question is why...  or am I doing something wrong?  I've tripled checked the settings, and also verified them by setting the Universal Support based on the chart in the "Grinding Angle Adjustment" booklet.  The distance between the Universal Support is the same both directions, the grinding angle is the same both directions, the distance (in testing) between the Adjustable Stop and the knife edge is the same... so why is there such a difference in the distance of the markings?  Probably something obvious I'm overlooking... but want to make sure I'm not doing something incorrect.  (This really surprised me, and if I'm doing something wrong... can't figure out why it works...).

Any other comments/suggestions appreciated.  I did this prior to finding the "Grinding Angle Adjustment" booklet, (and was pleased things matched up once I figured out 'S'...),  and am thinking there's probably a different way to set the wheel markings (math) that may be more accurate?  But so far this has worked, and I would think easily repeatable.  Obviously you can mark whatever angles you want, use a different reference, etc... so any ideas welcome.  (Or if this was done somewhere before, point me that way...).

Hope it helps, (and makes sense).

[Jan]

Thank you for posting your angle setting method. Good food for thought!

Jan

[Ken S]

Interesting innovation, CB.

These different ideas all seem to have a common thread. While the Anglemaster works very well with larger flat areas, like chisel bevels, it can be difficult to use with small bevels, like knives. Very good lighting can help this, however, a small beveled surface is still small.

I believe the ideal situation is for a sharpener to become fluent with all of these methods and have a variety of techniques at his fingertips.

Keep exploring; you are doing good work.

Ken

Comments may take a little longer to formulate. My last millenium mental processing unit does not have warp drive.

[cbwx34]

Thanks for the replies.

I think I solved the distance issue.  I had assumed that the positions for the horizontal and vertical Universal Support positions were essentially a "mirror image"... so thought the distances should be the same.

But in looking at it from the side this a.m., I realized that the horizontal bar is above the center of the stone, while the vertical bar is behind it (in relation to where you're sharpening.  So, the distance to reach 90° is greater on the horizontal side.

I agree that learning various methods/techniques are ideal... or at least trying them and see what works best for your particular situation.  All the various methods I've seen on here are great.

[Jan]

You are correct, the USB sleeves are asymmetrical with respect to the shaft, but I do not see a problem here. I am wondering if your method can work correctly with arbitrary distance between the Adjustable stop and the knife edge (projection length).

Jan

[Ken S]

Interesting observation about the position differences in the horizontal and vertical sleeves (Tormek's word). That is useful information; good seeing!

We keep pushing back the frontiers,

Ken

[cbwx34]

You are correct, the USB sleeves are asymmetrical with respect to the shaft, but I do not see a problem here. I am wondering if your method can work correctly with arbitrary distance between the Adjustable stop and the knife edge (projection length).

Jan

Not sure if this answers your question...  but as a test of what I think you're asking, I took a knife and mounted it in the standard jig, and set a 20° bevel (checked with the AngleMaster).  Then marked the bevel with a Sharpie, and remounted it in the Small Knife Holder.  This time, set the 20° angle using the mark on the wheel, and then turned the wheel by hand, to see where the Sharpie was removed.  Looked to be pretty much spot on? (Picture attached).

Thanks for the question.

[Jan]

Thank you for this test! It shows that your method works for various distances between the Adjustable stop and the knife edge.

Jan

[cbwx34]

Well, it didn't work on the top (vertical) support.  I repeated the same test... mounting the knife in the jig everything lines up (20° line, AngleMaster matches).  But when I put it in the Small Knife Holder, and set the 20° angle using the mark on the stone... the actual measurement is around 23-24°.  (I repeated it several times... seems consistent).

Not sure why it all works on the horizontal support, and works with the knife mounted in the jig on the vertical support, but not in the SKH.  Hmmmm.

Thought I'd pass it along.  More testing. (Ideas welcome).   

[cbwx34]

Well dang... it doesn't work after all.  (Or, sorta works, by coincidence).   

After staring at the diagram in the "Grinding Angle Adjustment" booklet... and sliding the Universal Support in and out with a ruler laying across it, it's apparent (rather obvious in hindsight), that the angle changes.

So, I simply laid a ruler between the Support and wheel at a mark, and measured the angle change with a digital gauge.  Turns out, on the horizontal support it's not that significant.  I didn't measure, but 10 turns of the Micro Adjust is only a degree or so.  (And most of my testing was done this way).

But the same change on the vertical support is around a 5 deg. difference.  (Probably due to the Wheel/Support relationship I mentioned earlier).

So, guess if you sharpened off the horizontal support, and there wasn't a significant change in "projection length"... close enough to get away with?     Might be close enough to consider... it's a quick way to do it.

Thanks for the feedback... gave me a (needed) different perspective to look at it.

(Freehand looking better and better).

[Jan]

Thank you for your explanation. You are a fair person. I will sleep well now. 

Jan

[cbwx34]

Haha. Please don't lose sleep on my account. 

I like to experiment... they don't all pan out.  (Bummer it was the first one in this forum)...

The wheel sometimes throws me a curve. 

[Ken S]

Welcome to the club, CW. I have two small knife platforms which didn't work very well. (I used the platform jig; Herman's design with the platform of the scissors jig works better.) I have a spare microadjust nut from a project to use it as a lock nut - another not so brilliant idea, as well as a bunch of also ran parts from other ideas.

However, I also have several kenjigs, which, in my humble opinion, work well. Innovation is a mixed bag. Keep innovating!

Ken

[cbwx34]

Thanks.

There goes my dream of selling CRPs (Chopstick Reference Pointers).... 

[Ken S]

Don't get hung up with minor details; lots of things don't actually work. 

Ken