The burr won’t go...away

T

tommytman

Joined
Aug 12, 2019
Messages
303
I’ve been working on a buck spitfire. I decided to put a 30 degree bevel on it with a sharpmaker. I did that with diamond and then went to brown stone and then to the fine stone. It is very sharp and I didn’t seem to have an issue getting rid of a burr with 30 degree bevel.

then I decided to experiment with putting a 40 degree micro bevel. I used the fine stone and could raise a burr in one stroke. But all I could do is move the burr one side to the other. I could not get it to go away. How can I kill that pesky burr?

I then simply Went back to a 30 degree with no microbevel.
 
I would speculate that you weren't raising a burr at 40 degrees, you were just rolling the existing apex back and forth.
 
Hmmm. So what do I do in that situation? Or what do I do to tell if I have a burr or rolled edge?
 
It's not a good idea to put a microbevel on an already keen apex. What I would do is cut into a fine stone to dull the edge slightly, then form the microbevel.

I don't think it really matters what form the "unwanted" steel at the apex takes, as long as you remove it.
 
OP, can you cut paper towel or tissue paper cleanly at 30 degree?
If so, can you do the same after cutting into hard wood a few times?
If not, then you most likely left a wire edge at 30 degree.
Just my 2 cents.
 
looks like it was a burr. It was very small. I was able to remove it with very light pressure and drawing the blade across the ceramic (pulling straight back as opposed to the normal sharpening motion) at a higher angle. thanks for all the tips guys.
 
This may be the part I don't understand. lets say I work up a burr with a course stone on both sides of the blade and then get rid of it. but now I wan tot move to finer stones. Do i need to work up a burr with each successive finer grit stone and get rid of it at each grit level?
 
tommytman said:
This may be the part I don't understand. lets say I work up a burr with a course stone on both sides of the blade and then get rid of it. but now I wan tot move to finer stones. Do i need to work up a burr with each successive finer grit stone and get rid of it at each grit level?
Click to expand...

If you create a burr at the first stage, and then carefully minimize it or remove it, you don't have to deliberately create a burr in the following steps. But there's still a good chance you'll create one anyway. That's nothing to worry about... just make sure to lighten your touch as you go, so the new burrs, if any, will be smaller, thinner and easier to clean up as you progress through the finishing steps. Progressively lighter pressure is everything, as you get closer to finishing. This will ensure that the finished edge is even finer, keener and still durable when you finish. As the edge thins out, it becomes exponentially easier to accidentally roll or burr the edge if the pressure is just a little too heavy. If it seems like the edge is still burring or rolling as you progress finer, that's the cue to let you know you need to keep reducing pressure.
 
BTW, if you do create a microbevel in finishing up, you really DON'T want to burr the edge in this step, if possible.

Microbevels are best when they're created with only a very small number of featherlight passes, maybe 1 - 3 at most per side. And in working at a wider angle to create the microbevel, lateral pressure will be even greater against the apex. So, in making the micro, you want your touch to be the lightest it can possibly be. Check sharpness after each and every pass, so you don't go too far.

I've been tinkering with using microbevels lately, as applied at 40° inclusive on the SM's medium rods. I've found they turn out best only after I've sharpened at the original bevel angle (my preference: ~ 25° - 30° inclusive) to a very keen edge. Then, and only then, do I give it just a few passes with my lightest touch at 40°. If done too heavy or in too many passes, it'll degrade sharpness more than it'll improve it. It's also easy to degrade it with too much stropping afterward - more so with compound. But if it's done with the lightest touch, fewest passes and little/no stropping after, it adds a noticeable aggressiveness and stability to the bite at the edge.
 
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