Advanced Sharpening : Blade Asymmetry

[ksskss]

This topic is about sharpening a blade and controlling the edge asymmetry to match the blade's asymmetry using just a single angle. I'm hoping to do more Advanced Sharpening topic videos and this would be the first one.



http://www.youtube.com/watch?feature=player_embedded&v=dDsWh_M7Rek

---
Ken

[LumberJ]

Interesting take and method. It should be good for people to see how assymetry works even when using the same angle. Are you sure you are holding the 0 angle with your hands? I understand what your trying to accomplish with that setup and so I'm not trying to quibble over it just curious

[Fred]

But use belt sanders for other people's knives, not your own.

[ksskss]

Regarding the zero angle - it is basically with the abrasive surface flush with the side of the knife. Now in this video the side of the knife itself has an angle to it, so being flush to it is what I mean as opposed to turning the whole blade to a zero degree side like a yanagi.

Properly used a belt sander does have it's place. In this instance, the main use was for speed as was the belt selection. I spent 4 minutes going from a 50/50 to a 0/100 and back to a 50/50 and 100/0 grind. This compresses the time factor to demonstrate the point of doing asymmetric bevels in a time frame that won't lull the listener into inattention. It's also why I used a 'beater knife' for the demo as I wouldn't grind that much metal off of a good knife going from one geometry to it's opposite on a good blade.

Properly used, belt sanders have their place, BUT when I want a very precise edge, it's time to get out a Gizmo or EP.

---
Ken

[LumberJ]

Gotcha on the angles thing think holding a knife level in that situation takes some skill. As for precision I don't use a measuring and or guided device but I would never call my edges imprecise. Though that is an unrelated and differing matter I don't wish to sully this quality thread with. To each his own though.

Personally I think there is way too much overthinking going on over the whole assymetry idea. Just put whatever bevel you like on the front side of the knife and either deburr the back as flat as you can or deburr at whatever back bevel you'd like. I have always been more of a do it and figure it out as you go type of guy though and I understand some people want more info to start on than that.

[ksskss]

Thanks, I appreciate your comments. Yes, this topic does sometimes start looking like a debate on how many angels can fit on the head of a pin or (ref Gulliver's travels) which side of the egg you should crack an egg on. If you want to use my initials as a mnemonic, KSS could stand for 'keep it stupidly simple' Doing it at different angles on the two sides is an unnecessary complexity. IMHO, this is advocated to promote a sense of mystery about what should be a simple topic.

In the end, this is basically a wheel alignment problem and you tweak the edge to make it cut straight - or deal with a bad alignment with 'technique', the latter not being my preference.

On a belt grinder two things have a big effect on this (doing a zero grind) being easier - a variable speed (I use LOW speed) and an ON/OFF footswitch. I like to use BOTH hands to get the blade in perfect position while the belt is off and THEN apply power, as opposed to trying to get a perfect flat landing on a spinning belt. I also find I get enhanced precision freehanding on a stone OR belt setting the angle of the stone/abrasive surface, but that will be part of the topic of the next video. Not the extreme precision of an EP / Gizmo, but a very respectable and usable level of precision.

For holding a knife horizontally, it is useful to use a bubble level to 'calibrate' yourself to 'get' what is true horizontal, but don't bother to use this in actual practice as the movement causes the bubble to move all over. For this purpose just get an app for your iphone or splurge and get a Wixey or angle guide.

---
Ken

[LumberJ]

Well said sir