Knowing the edge angle...

[einsteinjon]

The recent Spyderco sharpness thread brought a question to mind that several posters discussed. How do you know what the edge angle of your knife is? This was the first I had heard about Spyderco doing 30* inclusive (I would have thought 40*), so other than Sal saying they shoot for 30*, how do you know what the angle of your knife is? Do you just hold it to the Sharpmaker and see which angle looks like it matches the closest? Is there some sort of trick to figuring it out in some other way?

Thanks for the responses everyone! :thumbup::thumbup:

 

[zyhano]

Use a magic marker on the edge so the edge is marked with ink. Do a couple of strokes on the sharpmaker and see where the ink has come off. if on the top of the edge (towards the spine of the blade) the angle is too steep. if only on the cutting edge, the angle is to shallow (unless you have a backbevel of 30 deg, which is essentially an edge with two different angles, the shallower one is the cutting edge).

when doing it manually, the magic marker trick works the same of course

 

[cgmblade]

I use a black magic marker also. It's a good, easy way to estimate the edge angle. After a few strokes on whatever sharpening system you use hold it up to a bright light. A magnifying glass or jewelers loupe helps. What you want to see is that you are taking off the ink evenly along the whole edge bevel. If you are only taking the ink off the shoulder then the angle is too steep (in my case greater than 20*). If you are only taking the ink off the very end of the edge and not off the whole bevel then it's too shallow (it's really 15* and your sharpening at 20*).Hope this helps.

 

[einsteinjon]

Thanks guys. That definitely helps!

 

[Outdoors Fanatic]

The recent Spyderco sharpness thread brought a question to mind that several posters discussed. How do you know what the edge angle of your knife is? This was the first I had heard about Spyderco doing 30* inclusive (I would have thought 40*), so other than Sal saying they shoot for 30*, how do you know what the angle of your knife is? Do you just hold it to the Sharpmaker and see which angle looks like it matches the closest? Is there some sort of trick to figuring it out in some other way?

Thanks for the responses everyone! :thumbup::thumbup:

I start wih the 30 degree slots, If I'm able to get my knife sharper at this agle, then it means I'm using the right slots... If not, I use the diamond rods to bring it down to 15 degrees per side. I don't mess with the 40 degree slots, that's big chopper and axe territory for my taste.

 

[Jason B.]

Using the sharpmaker as a guide will only get you close to the angle, don't forget to account for natural variations in your hand movement.

You can also measure the height of the spine from the stone and height of the blade from spine to edge and do a little math to get a round about angle.