Belt sharpening with 1x42 kalamazoo, can't get burr on the other side.

[kalamazoo52]

I found an old thread on here about belt sander sharpening with the opposite problem of me: https://www.bladeforums.com/threads/burr-removal-problem.1674126/

this guy couldn't remove the burr, I can't get it to the other side. I have a kalamazoo with the adjustable arm, so I can set the machine to 20 deg and just pull it across straight. My dilemma? The first pass, I get a perfect burr all the way down. I can feel this burr very easily. My problem? When I flip the knife over to sharpen the other side, I don't get a burr, it disappears. And It's not very sharp at all. I tried troubleshooting myself to see what the problem was and im honestly not sure. I would reset the edge by intentionally damaging it, then go at it again, get a burr, try the other side, burr disappears, it's still dull.

I'm not really sure what to do. I watched the two J. Nielson videos on belt sharpening on youtube. I just for whatever reason cannot get the burr to appear when I sharpen the second side, nor get it very sharp. I am using a 120 ceramic belt...and I'm obviously not going to mess around with any higher grit belts because there's no point if I can't get the burr to appear when I switch sides.

I am very good with hand sharpening with my KME. I can get a knife stupid sharp with that, and have no problem establishing a burr on both sides with that, but I am moving into belt sander territory because of high volume.

Help would be appreciated!!!

 

[Blade Lab]

My guess is that you're angle is too low on the opposite side, so you're hitting the shoulder instead of the bevel. Here's what I would do if I was you:

* Use a knife with a relatively wide bevel (sharpened on KME or whatever);
* Sharpie both sides of the bevel;
* Use the highest grit belt you have and do one pass on each side;
* Check to see where the Sharpie was removed.

In my experience, it's harder than one might imagine to hold a blade perfectly flat on both sides -- especially if you're looking at the flat of the blade for reference (because a typical primary grind is anywhere from 1-5°). Instead of looking at the primary grind, try to find a surface on the knife that actually is flat to use as a reference. If the handle is flat that might work. Worst case scenario -- focus on the ricasso.

 

[FortyTwoBlades]

I'll second the above advice. Chances are you're hitting the shoulder on the reverse face instead of the apex. This can be the result of the jig you're using, the reference method you're using, or a difference caused by handedness bias, etc. but whatever the cause of it, it's unlikely you're hitting the apex on the backside if you're able to get it easily on the obverse face but not the reverse.

 

[kalamazoo52]

I think you are both right, but I still can't get the burr on the other side. I think this is because this requires me to hold the knife with my left hand which is my non-dominant hand, so I mess up the technique. I will keep trying....

 

[FortyTwoBlades]

Fortunately the more you do it the better your muscles will attune to the process. I grind blades freehand almost every day, including on a Kalamazoo 1x42, and eventually developed so much of a feel for it that I no longer have to think about it.

 

[kalamazoo52]

Fortunately the more you do it the better your muscles will attune to the process. I grind blades freehand almost every day, including on a Kalamazoo 1x42, and eventually developed so much of a feel for it that I no longer have to think about it.

Do you have any tips and tricks for the kalamzoo?

 

[FortyTwoBlades]

I use mine without the platen and the key is mostly to just have it at a comfortable height and to not let the tip of the knife cross the centerline of the belt.