Show your Paper Wheel edges

A niece of mine is an avid amateur Chef (but not yet a knife afi), and this black ceramic knife (a rebranded Kyocera) is one of her favorites in the kitchen, as due to the tougher blade material the edges can be made thinner and thus the knife cuts better than a white ceramic version.
Longtime use however (not always on a suitable cutting board) plus storing it unprotected in a drawer between a bunch of steel bladed knives had blunted the edge to a point next to unusable, complete with quite a lot of (micro) chips and a broken tip.

This is the knife as it was when i received it.
(when you click the pictures 2 x you can see the chips clearly)

This is the knife after sharpening.
I reprofiled the rather bad factory edge to an ever so slight convex edge of +/- 25 degrees inclusive, and the sharpness is just hairwhittling (only towards the root, not to the point)
It easily slices single layer toiletpaper (torn apart 3-layered version) and a tomato of course.
Removing the chips and setting the new bevel was done with a Tormek T7, refining & convexing with a Paper Wheel coated with 15 micron diamond compound, and semi-polishing with a second Paper Wheel coated with 6 micron diamond compound.

Specs:

Overall length: 11.0 inch (28,0 cm)
Blade length: 5.8 inch (14,8 cm)
Blade thickness: 1,84 mm
Blade type: black ceramic / saber-hollow
Thickness behind the edge: 0,4 mm

The first clip shows the slicing of a piece of standard 3-layered toilet paper, for the second clip i peel off 1 layer and slice the remaining 2 layers, and the third clip shows the slicing of just the remaining single layer of toilet paper:

Slicing a tomato:

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 lightly 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:

The owner of this Sebenza 25 personally checked out several of this model at the dealer (Knivesandtools NL), and all of these Sebenza's had worse edges than the one he finally bought, but he already knew someone who could fix that.

And i've had quite a few more brand new CRK's come in this way (with overly large edge angles and/or completely blunt.

For several years now Knivesandtools send unhappy CRK customers to me, which is nice, but of course shouldn't be necessary with a brand new knife, especially a CRK which always comes with a card stating that the knife is very sharp.

Spyderco in general can do a much better job.

Wootz/Vadim testing heat build-up in the edge when using Paper Wheels with diamond compound:

He never told me in our e-mail conversations, but i recently found that he mentions me by name in the on-screen text,

Vintage Al Mar Denali mid-backlock folding knife with hollow ground blade from the 1980's and made in Japan. (probably by Moki)

The cocobolo handle is inlayed with a gold shield picturing a fighter plane and the text "United States Navy Fighter Weapons School".

The 1986 movie "Top Gun" with Tom Cruise and Kelly McGillis was partly filmed on the grounds of this elite school for US Navy pilots.

Bernard Levine thinks this version with the gold shield was a special edition, not standard production.

The original edge measured about 35 degrees inclusive and wasn't really sharp, so i changed the angle to 30 degrees inclusive with a treetopping sharp bling & bite finish.

GEDC9163.jpgGEDC9166.jpgGEDC9155.jpgGEDC9153.jpgGEDC9154.jpgGEDC9150.jpgGEDC9160.jpgGEDC9149.jpgGEDC9156.jpgGEDC9146.jpg

Specs:

Length open: 17,3 cm

Length closed: 10,0 cm

Blade length: 7,5 cm

Blade thickness: 3,0 mm

Steel: Masahiro RS30 stainless steel

Hardness: 57-58 HRC (?)

Handle material: Cocobolo wood & satin stainless bolsters on brass liners

Handle thickness: 11,0 mm

Lock type: Mid-backlock

Weight: 100 grams

Recovered some pictures from an old harddisk.

Several years ago i got sent these two user Emerson folders from neighboring country Belgium; a Commander model with a Krein regrind and a CQC7 model.

The owner was unable to get them sharp again with only his Sharpmaker, and the request was also to give the new edges a bit of bling.

As they came in:

After sharpening/polishing.

On the CQC7 i made the asymmetric bevel a bit wider to remove all different scratch patterns, and just touched up the existing mini-bevel on the other side.

Both knives could now be easily touched up on the Sharpmaker again and the owner was happy,

Currently busy with the same mod of another Gerber Applegate-Fairbairn folder like i showed earlier a few pages back.

This is how the knife looked when i received it from the owner, still with a single edge & an edge angle between 40 and 45 degrees inclusive.

And this is how the knife looks after grinding the new edge on the back of the blade & trying to match it with the reprofiled edge on the other side.

The scratch pattern complete with burr remains still present on the apex comes from a Rubber Wheel coated with ~ 170 grit diamond powder & wax.

The idea was to make the 2 edges / 4 bevels as visually similar in width & curvature as i could, with a specific edge angle of ~ 35 degrees inclusive, without damaging the names on the blade, and to create a new point that would be centered as much as possible.

Trying to achieve all these things at the same time freehand, together with many visual checks with a Victorinox loupe in between passes isn't easy, so i took my time.

Below you can see the end result after refining the initial edges with a Paper Wheel coated with 15 micron diamond compound & deburring with a second Paper Wheel coated with 0.25 diamond compound.

Both edges are treetopping sharp.

This is how Applegate intended the knife to be, a true folding dagger.

It can still be carried in your pocket, but the top edge is only about 2-3 millimeters inside the handle, so when deliberately trying i can just feel the apex with my index finger.

Now the thumb lugs stop on the grooved linerlock tab, so it would be easy to use a file or a Dremel on it's surface to lower the blade a tiny bit deeper inside the handle for added safety, as there is some room for it.