BK-11 and Sharpmaker

[numbersman]

I am having trouble sharpening this particular knife with my SharpMaker. It flips between sharp and blunt during the sharpening process. It goes sharp and then blunt again, and repeats. I don't have this trouble with, say, my Izula II, which is a pretty similar knife. That is absolutely razor sharp. But I can't get this one sharp enough to cut paper. I have been using the SharpMaker for years, and am pretty confident in my technique. But this one knife is giving me fits. Any suggestions?
numbersman.

 

[Spartan00]

Sounds like a burr to me as in its forming a burr and feels dull then you knock it off and it's sharp . You have a strop? Next time it goes from sharp to dull do a few stopping strokes on a strop or a belt and see if your knocking the burr off .

Could be a few other things off the top of my head but you said your confident In your technique . If your sure your not moving the knife and possibly rounding the edge then check for a burr .

 

[bucketstove]

I am having trouble sharpening this particular knife with my SharpMaker. It flips between sharp and blunt during the sharpening process. It goes sharp and then blunt again, and repeats. I don't have this trouble with, say, my Izula II, which is a pretty similar knife. That is absolutely razor sharp. But I can't get this one sharp enough to cut paper. I have been using the SharpMaker for years, and am pretty confident in my technique. But this one knife is giving me fits. Any suggestions?
numbersman.

Hi, how many times have you sharpened it? Have you cut off the edge ?
How are you deburring, double angle passes?

Try this,
freehand/eyeball a 40 degree per side angle
(double the available sharpmaker setting),
and do 1-2 light (under 100 grams) alternating passes per side
on the flats of the brown medium grit rods,
check for burr, and do another 1-2 alternating pps if needed,
then do 5 alternating at your finishing angle on medium grit brown rods,
then do 5 alternating at your finishing angle on fine grit white rods
then stop

For more detailed/advanced sharpmaker steps see Sharpening Curriculum / Trouble sharpening super blue - Spyderco Forums

 

[numbersman]

I strop on a piece of leather belt, and it isn't helping. I'm open to any suggestions!

 

[HeavyHanded]

Is the BK11 new out of box?

It might have been cooked when sharpened at the factory, and a bit of metal will need to be removed to get to the good stuff. In the meantime stop at the medium rods and let it cut with some tooth till the dud metal is worn away from a handful of sharpenings - you'll get better life from it.

if its been around and resharpened a bunch of times, I don't have an explanation - the Izula 2 really is nearly the same in pattern and steel type. My BK11 is very easy to sharpen and tune up, holds a good edge reasonably well too.