Spyderco Forums

I'm guessing this was posted before, but it's news to me at least. An easy way to figure out your edge angle is to take out your calipers and measure the thickness right behind the edge bevels and the length of the edge bevel (from the factory, shallower grind to the edge) and use the inverse tangent function.

So an example is my Manix 2 M4. The width is 0.032 in and the length is about 0.068 inches. So punching the tan^-1 and 0.0345/0.068 in the parentheses and you get about 25 degrees. It isn't exact, but gives you a good estimate.

The method I use,and maybe unconventional to some folks,I hold the blade horizontal under a light and slowly rotate the the blade until I see the light reflect off of the bevel, and take my angle finder and lay it against the side of the blade and it will give me the angle of my bevel.

Very interesting methods. Especially the first one using a math formula. That would be new to me and very interesting. I don't have the tools to do it though.

I have an Edge Pro sharpener and I'm not trying to sell it, just mentioning a benefit it provides other than sharpening. It can be set to any angle, not set to notches every 3 or 5 degrees or something like some other sharpeners. So I take a knife, mark it with a sharpie and set the EP angle so the marker is removed from a bevel. Then just see what angle the EP is set to. That is the per side angle of the edge. Double it of course to get the inclusive angle. I would never advertise the EP as an angle finder but it is a sharpener that will give you that info. There are a couple of drawbacks. The stone has to be new to give an accurate measurement. Also the stone has to touch the bevel. If you have a pretty mirror bevel you wouldn't want to touch a stone to it, even a very high grit. I made a strop for the EP with a piece of leather glued to a stone blank. It will remove the marker without scratching the bevel. I could use that as long as the leather is 1/8" thick.

You are assuming of course that the marks on the EP are accurate. They are very close. I checked them with a round level a couple of years ago. You also could use an angle cube to check them. I don't have an angle cube.

Just some thoughts.

Jack

Taking physics class and pre-calc classes, trig gets on your mind. It made sense and would be less detrimental to the knife/edge than using a sharpening system to figure out angles.

Interesting, but I have a redneck way to judge my blades. I sharpen my knives until they cut hair and then I use them until they don't and then repeat.

BAL wrote:Interesting, but I have a redneck way to judge my blades. I sharpen my knives until they cut hair and then I use them until they don't and then repeat.

What do you know? We have a caveman in the group. :) Kidding of course. That is a tried and true method you have adopted. :D

Jack

I'll take your caveman method and raise you my inverse caveman method of looking up the edge angles online via forums lol

Check out the link below for VERY accurate angles, especially helpfull with guided systems such as edge pro.

http://www.chefknivestogo.com/anglecube.html

Frapiscide wrote:I'm guessing this was posted before, but it's news to me at least. An easy way to figure out your edge angle is to take out your calipers and measure the thickness right behind the edge bevels and the length of the edge bevel (from the factory, shallower grind to the edge) and use the inverse tangent function.

So an example is my Manix 2 M4. The width is 0.032 in and the length is about 0.068 inches. So punching the tan^-1 and 0.0345/0.068 in the parentheses and you get about 25 degrees. It isn't exact, but gives you a good estimate.

This is the technique I used in my recent thread about low edge angles for the Para 2M390, here.

It works ok for flat/straight bevels but not convex/appleseed variations (and hellish-fiddly for micro-bevels).

If you are lazy or can't find a scientific calculator, there are some handy "cheats" online where you type in the known variables of the triangle and it churns out the unknowns. Like this one. (obviously you'll need to double the angle produced if you want the "inclusive" edge angle.)

rjowen0984 wrote:Check out the link below for VERY accurate angles, especially helpfull with guided systems such as edge pro.

http://www.chefknivestogo.com/anglecube.html

I've been looking at that thing for quite a while. Mainly, I can think of other uses for it as well. I've thought I could tie it to a 36" level for extremely accurate building, especially when you want a certain level of slope on something. The first thing I'd use it for is to check the marks I put on my EP to mark angles in 1 degree increments in addition to the standard marks which are 3 degrees apart.

Jack

Lord vader wrote:The method I use,and maybe unconventional to some folks,I hold the blade horizontal under a light and slowly rotate the the blade until I see the light reflect off of the bevel, and take my angle finder and lay it against the side of the blade and it will give me the angle of my bevel.

This makes sense, but I think you'd need to hold the blade so that the bevel was in line with one eye, with the point of the blade (actually, the straightest line of the beveled part of the blade) going directly away (or toward) the eye. Just making sure I understand.

BAL wrote:Interesting, but I have a redneck way to judge my blades. I sharpen my knives until they cut hair and then I use them until they don't and then repeat.

Well I never considered myself a redneck, but your post makes me wonder...

jackknifeh wrote:I've been looking at that thing for quite a while. Mainly, I can think of other uses for it as well. I've thought I could tie it to a 36" level for extremely accurate building, especially when you want a certain level of slope on something. The first thing I'd use it for is to check the marks I put on my EP to mark angles in 1 degree increments in addition to the standard marks which are 3 degrees apart.

Jack

The problem with "trusting" the marked angles on guided systems is when you start becoming obsessive then certain variables such as stone thickness and distance of blade from blade table affect the angle or the accuracy of premarked angles. Then the only really accurate way is to use a drill stop collar to adjust for stone thickness variation and the angle cube to set desired angle starting with the final stone or strop then adjusting the arm height via the stop collar for each stone. Slightly OCD!

[quote="-F1"]This makes sense, but I think you'd need to hold the blade so that the bevel was in line with one eye, with the point of the blade (actually, the straightest line of the beveled part of the blade) going directly away (or toward) the eye. Just making sure I understand.



I`m actually looking down at the blade from a birds eye view,and the light source is between me and the blade. This works real good for me.I also use the lansky sharpening system. I must be doing something right,it really works.

Lord vader wrote:I`m actually looking down at the blade from a birds eye view,and the light source is between me and the blade.

That makes sense. I just tried it with this angle locator I bought at HD. Stick the angle locator on the blade using the magnet (perpendicular to the edge, of course), and peer directly over the bevel. The light can be up or down slightly, as long as it's not to the left or right of the plane defined by the bevel and your eye. My angle tool told me I had 17 degrees, which is about what I expected. It's just an estimate, of course, because the overall blade design changes the angle of the tool. The actual value will always be somewhat higher than the readout. Anyway, thank you!

I second the notion to use an angle cube on the Edge Pro .... :)

I use the angle cube on my WEPS. It gets me to within a tenth of a degree every time.

TedP