Sharpening angle question

[lacourla]

I got an Edgepro Apex a couple of days ago and while not undertaking anything to radical (just matching factory angles) I've managed to put blistering sharp edges on all my knives....until now.

I just picked up a Lightfoot 458 folder and have matched the original edge angle (appears to be about 30-32 degrees ) following all the steps that had previously yielded amazing results. Except this time, while the edge feels really sharp on the "thumb" and passes the hair shaving test, the knife fails miserably at paper cutting. I mean it just drags and tears newspaper unless I hold it at just the right angle and then it cuts pretty smooth.

Is this to be expected with this heavy of an edge angle or should it slice and push cut newspaper as well as my other knives even though they have edges in the 18-21 degree range? Any idea why a maker would put this heavy of an edge of a 3.25" folder?

Finally, if I choose not to lower the angle for aesthetic reasons is this the best performance I can ever expect to get out of the knife?

Thanks for all your help.

 

[Cliff Stamp]

... passes the hair shaving test

What does this mean to you exactly, how are you doing the cutting.

Is this to be expected with this heavy of an edge angle or should it slice and push cut newspaper as well as my other knives even though they have edges in the 18-21 degree range?

What is kind of surprising is that it shaves but doesn't slice newsprint. Slicing newsprint is a low test of sharpness, knives will continue to slice that paper long after they have stopped shaving. Have you tried not going all the way to the extreme polish and checking how it cuts paper?

Any idea why a maker would put this heavy of an edge of a 3.25" folder?

Less metal has to be removed when setting the edge initially, i.e., it is cheaper.

Finally, if I choose not to lower the angle for aesthetic reasons is this the best performance I can ever expect to get out of the knife?

I would be more concerned about general cutting ability than just sharpness and that is indeed going to be very low when the angle is that high.

-Cliff

 

[lacourla]

What does this mean to you exactly, how are you doing the cutting.

Just the typical putting the blade on my forearm and pushing away from my torso, with the grain of the hair.

What is kind of surprising is that it shaves but doesn't slice newsprint. Slicing newsprint is a low test of sharpness, knives will continue to slice that paper long after they have stopped shaving. Have you tried not going all the way to the extreme polish and checking how it cuts paper?

Yeah I have, it's like a butterknife at that point and only begins to shave when I put the polish on.

I guess the layman would be satisfied with it as that's the condition it was in when I received it, but after seeing the performance of a "sharp" knife I guess I'm going to have to contemplate bringing the angle down by at least 5 degrees. It's just that the blade has some complex grinds and I don't think I'm skilled enough yet to tackle them without rounding off the tip or hitting the higher parts of the blade. Oh well, I guess I'll have to send it in to Ben to do the initial reshaping for me.

Thanks for your help Cliff

 

[gunmike1]

I got an Edgepro Apex a couple of days ago and while not undertaking anything to radical (just matching factory angles) I've managed to put blistering sharp edges on all my knives....until now.

I just picked up a Lightfoot 458 folder and have matched the original edge angle (appears to be about 30-32 degrees ) following all the steps that had previously yielded amazing results. Except this time, while the edge feels really sharp on the "thumb" and passes the hair shaving test, the knife fails miserably at paper cutting. I mean it just drags and tears newspaper unless I hold it at just the right angle and then it cuts pretty smooth.

Is this to be expected with this heavy of an edge angle or should it slice and push cut newspaper as well as my other knives even though they have edges in the 18-21 degree range? Any idea why a maker would put this heavy of an edge of a 3.25" folder?

Finally, if I choose not to lower the angle for aesthetic reasons is this the best performance I can ever expect to get out of the knife?

Thanks for all your help.

Does it shave evenly on both sides, or did you only test one side of the blade? A burr would lead to good shaving on one side and little or no shaving ability on the other, along with serious edge durability issues, and the issues with cutting paper crappy unless at held at just the right angle, as you describe. Also, at those edge angles I'm not sure you can call that a knife. My lawnmower blade doesn't look that thick. Screw how it looks, if it can't cut what's the point? I would reprofile at least as thin as your other blades (actually, I would go thinner on all of them, but that's me). As Cliff noted, even if you do get it sharp it won't cut worth a crap because of the angle and thickness of the edge. If you need to send it to Ben Dale to reprofile, that wouldn't be a bad idea, the man can really sharpen a knife.

 

[lacourla]

Thanks for the input gentlemen....a knifes only a tool, right. I just got finished taking the edge down to 21 degrees. Only took about an hour from start to completion (that edgepro is something else). The difference is night and day, and it looks pretty darn good too! It now slices effortlessly through whatever I put the edge to (other knives withstanding).

I have certainly learned a few valuable lessons today, thick edges SUCK, what's the point of a knife if it can't cut, that the edgepro is an amazing tool, and that Bladeforums is truely indespensible.

Hmmmm, wonder if Rogaine works on arm hair?