The owner of this Sebenza 25 bought the knife brand new through an official dealer in the Netherlands, but although he was and is still very pleased with the knife itself, he soon found that the factory edge didn't cut too well.
He tried to improve things with the help of a Spyderco Sharpmaker and a leather strop loaded with some green compound, but to no avail.
So he sent the knife to me, and the first thing i did was to measure the edge angle.
According to my Tormek Angle Gauge it measured 50 degrees inclusive on the straight part of the edge, going up to 55 degrees inclusive from the belly to the point.(!)
This is how the knife looked before sharpening:
First i removed the apex of the old edge by cutting a few times directly into an old silicon carbide stone, after which i reprofiled it freehand on my Tormek SB-250 Blackstone to an even 30 degrees inclusive.
This was followed by a Paper Wheel with 220 grit SiC to smoothen the grindlines made by the Tormek, then refined with a second Paper Wheel coated with 15 micron diamond compound, and finally removed the burr with a third Paper Wheel coated with 0.25 diamond compound. (this leaves the 15 micron scratch pattern intact as much as possible to preserve bite)
The resulting edge treetops the hair on the back of my hand, can slice single-ply toilet paper, and survives a few cuts into my laminated testblock without any visible damage (checked under bright light with the loupe in my Victorinox SwissChamp)
This is how the knife looks after sharpening: