Taking off the burr

[jackknifeh]

ON A SIDE NOTE:

This regards guided sharpeners, like the Sharpmaker, where you have the stones/sticks set at preset angles on a base and you gently run the knife edge across the sticks going downward. The issue that I have is that the preset angles typically aren't the ones needed to work the edge at the preferred angle(s), like for jackknifeh's image below (and sometimes not even at the angles they're labeled at -- a simple protractor can reveal that)

Now I recently purchased a crock-stick setup for sharpening the few blades I have (Sorry, everyone - and especially Sal - it's not a Sharpmaker; like I've mentioned before, I've only recently started on knives as an interest/hobby), and future blades (may have to get a better set-up for harder steels; hopefully by then, I'll be more practiced). And it occurred to me that there MIGHT be a way to REDUCE the actual angles one sharpens at, by simply ROTATING the sharpener off-perpendicular. That way, when you gently run the edge across the sticks (along the triangle edge for the Sharpmaker sticks; not the flat), you're at the desired angle(s) needed. With a little bit of basic trigonometry, I even determined a formula for how much the sharpener would have to be rotated to reach the desired angle:

cos R = (sin D) / (sin A)

R = Angle off of perpendicular that the sharpener would have to be rotated (between 0 and 90 degrees)
D = Desired angle (per side) for sharpening (D less than A)
A = Actual angle of the stick in the sharpener (again, per side)

There's a long story on how to arrive at this formula.

The idea being that, with the addition of a simple protractor (maybe the same one you use to determine the ACTUAL angle of the sharpening sticks), a sheet of paper with a line drawn on it, and a good scientific calculator, one could practically DIAL IN the desired sharpening angle to work on the knife edge. Problem is, some of the angles needed to rotate the sharpener can be high (for example, to take a 20-degree angle down to 15 degrees, the sharpener would have to be rotated about 41 degrees off-perpendicular). Also, since the sticks are now no longer perpendicular to yourself, the length of the actual knife strokes would be different (possibly shorter for the stick now angled away from you, longer for the one angled closer). And there may be other problems that I'm not seeing ATM (if you think of something I'm missing here, PLEASE LET ME KNOW!!!).

Any thoughts? Something I miss? Do I need to take remedial trigonometry or consult a psychiatrist? (NOTE: I haven't done this to any of my blades YET; like I keep stating, I'm still new to all of this.)

What would be cool is if you could develope a "V" type sharpener like the Sharpmaker with 100% adjustable angles to hold the rods or whatever sharpening stone you want. Seems possible to rig something that would have a manual crank to turn which would move both rods at the same time and keep them at the same angle. Some sort of belt or chain and pulley setup. I don't know how difficult that would be. But if you are considering what you mentioned I'd say you have the motivation to explore other stuff. Or, depending on how much money you want to spend there are other sharpening systems available that are more versatile than a "V" type sharpener. The Edge Pro and Wicked Edge are the two I know of. They are capable of setting any angle you want that would normally be desired on a knife edge. Or, there is also an Edge Pal that someone designed and makes them to order. That system will hold about any stone you already own instead of needing to buy stones that mount in the WE or EP. It also is designed to be even more precise regarding setting the angle you want. But for most knives, especially EDC pocket knives the exact angle isn't that important. If you want a 15 dps angle and accidentally put a 13 or 14 dps edge on your knife you'll never know it. Not by every day use that is. Or before investing time and/or money in systems you might consider mastering free hand sharpening. However, while the systems control maintaining a consistent edge angle that is only controlled by your ability when free hand sharpening. It takes longer to become proficient but it also eliminates any little quirk that come with about any sharpening system. These quirks are not always bad. They are just things you need to learn to work with to get better performance from the tool. Just like a lot of tools.

Anyway, I'm sure we are eager to see what you come up with if you design something yourself. If you come up with something really smart make sure not to patent it so I can steal the idea and become a go-zillionaire. :)

Jack

[Cliff Stamp]

Anyway, I'm sure we are eager to see what you come up with if you design something yourself.

What he proposed is much simpler, just rotate the Sharpmaker (not tilt it) to adjust the angle.

[Ecchi-Spud]

Anyway, I'm sure we are eager to see what you come up with if you design something yourself.

What he proposed is much simpler, just rotate the Sharpmaker (not tilt it) to adjust the angle.

Precisely. Just simply turning the sharpener to try to get a more acute angle (which SOUNDS like it might be doable -- but I do worry that I'd be messing up the edge by not having the exact same strokes for both sides of the blade).

[Cliff Stamp]

By wooden mockup do you mean you whittle a wooden knife for someone to learn with using sandpaper as the stone?

Yes, something large like wood or foam where you can shape the angles and see what is happening and understand what has to be achieved on a physical level. This takes all of the magic/mystery out of sharpening and reduces it to a very simple forming operation. On a basic level it is no different to sharpen a knife than make a tent peg, they are both basically the same process, once just has tighter tolerances.

Let me ask about your two steps to make sure I understand what you said. It sounds like in step a) you put the edge apex on the edge and then in step b) you lower the angle to create a back bevel to thin the blade or edge right above the apex. Is this what you meant?

To clarify, this is how I introduce someone to sharpening :

Step 1 :

Provide them blades which have the edges I have prepared to take a micro-apex bevel and show them how to apply an a micro-apex bevel to that edge. This allows someone to produce a sharpness which easily shaves and slices newsprint and a lot of people can get push cutting sharpness with just a little practice, but most people don't care about that anyway. I normally use a DMT fine stone at this point or similar stone which is really easy to set micro-bevels, the Spyderco medium is another.

Step 2 :

Give them blades which are blunt and need the edge bevel reset and show them how to do that and get them to the stage that is ready for a micro-apex bevel. They know how to do that final step already so they have a very clear and focused goal and since they already succeeded this step comes just as easy. A King 1000 or Naniwa Superstone 400 are very nice stones to use here because they naturally are very muddy and will keep the edge from generating a significant burr.

If so, couldn't you do the steps in reverse?

Once you learn the method that is how it is done, yes.

About the "feel" or "touch" I feel when sharpening a knife. This can't be explained and it can't be taught.

The idea of being "in the zone" is one of those things which turns into a lot of mysticism and if that helps you then ok, but it is nothing more than an example of directed hyper focus. It is a particular subject of a branch of science. It is normally attributed to Csikszentmihalyi who named it (he called it the flow). He described it as a state of perfect motivation and immersion. This just means that a person gets into a state where they are completely involved in a particular activity or towards a particular goal. Can you teach it, sure, coaches do it all the time. The first stage of it is to always focus on the goal and visualize perfect results.

Now some people try to do things like say you can tell by the feel of the stone on the knife or the sound where you are on the bevel and this is true but it takes a lot of experience to get there. If you try to make a person focus on hearing that sound or trying to get some particular feel when they are learning it is likely to confuse and frustrate a lot of people. Especially when you change stones and steels which can make just as much difference. This is why I focus on the goal, the brain will take care of the rest. Just like you tell someone to balance themselves on a bike and they will as they learn to ride, the brain will make the goal happen.

[aesmith]

I think it would work the other way round. I'm just basing that on what you'd see if you looked straight at the sharpener with your eyes level with it. In it's normal position you'd see the 20 degree per side forming a truncated V. Tilt the base towards or away from you, and the apparent height would be less, while the width stays the same, making the angle wider.

[Ecchi-Spud]

I think it would work the other way round. I'm just basing that on what you'd see if you looked straight at the sharpener with your eyes level with it. In it's normal position you'd see the 20 degree per side forming a truncated V. Tilt the base towards or away from you, and the apparent height would be less, while the width stays the same, making the angle wider.

If you TILT the base toward you, or away from you, then YES, the apparent angle of the sharpening rods would increase -- and make it unstable (unless you put a wedge underneath the base). But if you ROTATE the base (keeping it level on the table or bench or wherever you have the sharpener on), the height of the rods remains the same, while the apparent horizontal distance between the top and bottom of the rod decreases -- reducing the angle. Eventually, as you rotate the base a full 90 degrees, the rod would appear to go straight up and down.

And the base would still remain stable; it's still flat on the table/desk/bench. You'd have the other end of the base (the one where you DON'T have the rods set in place; the one you hold with your other hand to stabilize) closer to or further away from you (depending on which direction you rotated the sharpener).

My apologies if I wasn't clear about exactly HOW to rotate the sharpener earlier.

[Brunzenstein48]

Whow. Splendid idea - Chapeau!