secondary bevel trouble

[SKOHH]

I have watched both Dave Martell and Murray carter's dvds on knife sharpening. Both are very informative and extremely helpful in their own ways. And being a weirdo I had to see both to compare technique and knowledge. Both speak of the secondary bevel, call me nuts but the jknives that I have do not have a secondary bevel. Or do they and im just blind and stupid? I have 2 misonos, a ux10 and a molybdenum gyutos as well as a ittosai santoku. Also, while trying to apply the secondary bevel, once I grind in the primary bevel even though I have raised the angle of the blade, I barely have a secondary bevel. It is so thin that it might as well not be there. Do I want to increase the angle on the primary bevel? I have quite a low angle on the blade for the secondary bevel but I didnt think that I should raise the blade more than 5-10 degrees when applying the primary bevel. :scratchhead:

Also, these knives were originally 70/30 grind (the misonos I mean), I have unintentionally made them 50/50. If I wanted to bring them back to the 70/30 edge, do I do that on the secondary or primary bevel?

Please...help!

 

[tk59]

You have no stock secondary bevel in the sense they are referring to. It sounds like you are applying a microbevel. In that case, sharpen the bigger bevels on both sides and then one or both sides raising the angle anwhere from 5-60 deg higher depending on the effect you are looking for. It's trial and error.

 

[SKOHH]

So should I not be trying to put on a secondary bevel? I was not trying to make a micro bevel.

 

[Andrew H]

I'm totally lost here. Can someone *cough* Tinh *cough* make a diagram?

 

[tk59]

The way we've chosen to define it on this forum, a secondary bevel is what you see on a Heiji, Zakuri, Carter, Yoshikane, etc. (Check out the pics of these knives.) The primary/cutting is a tiny bevel you often times don't really see in the pictures. In fact, folks that have never seen this geometry often don't realize there is one. Here's a diagram with the bevels labeled on a folder: http://faq.customtacticals.com/geometry/anatomy_folder.php. They are labeled opposite of what is accepted on this forum with the secondary bevel being the tiny, cutting bevel. Here's another one labeled the same way: http://www.cartercrafts.com/knifeinfo.htm. They also designate them the "edge" and the "grind."

 

[SKOHH]

I’m sorry for the confusion. I am looking to see if it’s a bad idea to create a secondary bevel on my misonos (I would attempt on the ittosai if it wasn’t damascus). When I attempted this, I ground in the secondary bevel and then ground in the primary bevel (cutting edge). I raised the angle maybe 10 degrees (complete guess there); when I did this I had a small line that was my "secondary bevel" while my primary bevel was rather large. Basically it looked like the opposite of what it should be with a large secondary and tiny primary like tk described. Should the primary bevel be much higher than what I raised it to make that barely there cutting edge? Is this because you want a "strong" edge on a very thin blade? I appreciate you guys trying to help me on this.