Takamura R2 Gyuto sharpening

[kwakster]

On this knife the Tormek was not used for the actual sharpening of the edge, but in a very important supporting role.

Right hand Takamura R2 Gyuto 210 mm from a local Chef, who got it as a birthday present from his wife.
The knife has already been used for two months in the commercial kitchen and it was time for it's first resharpening, which i did yesterday on a Paper Wheel with 15 micron diamond compound and then deburred on a second Paper Wheel with 0.25 micron diamond compound.
The idea was to make an edge that would do both slicing & pushcutting well, and also to remove as little steel as possible from the fine and thin R2/SG2 blade @ 63-64 HRC.
The new edge measures +/- 20 degrees inclusive and can whittle a chest hair from root-to-tip at about 4 centimeters from the point of holding, and after a few test cuts into a old piece of beechwood cutting board.

I took these pics with an old Ipad and actually wanted to erase them again as being not good enough until i enlarged the last picture twice.
At first i thought i saw small dirt spots on the new bevel, but those tiny white specks were actually the sliced off peaks of the micro-dot structure on the inside of the flimsy plastic blade protector sleeve.















Total procedure:

- Repairing the point of the knife (about 2 mm was broken off) was done on the Tormek SB-250 stone by grinding the back of the blade until there was a new point.
- Flattening the old edge was also done on the Tormek (by grinding off about 1/10th of a mm on the side of the stone.
- Sharpening to burr was done exclusively on the 15 micron Paper Wheel.
- Deburring was done exclusively on the 0.25 micron Paper Wheel.
- Rounding the heel of the knife was again done on the Tormek (by grinding off a tiny bit of steel on the side of the stone.)

[kwakster]

The owner of the Takamura R2 just sent me the link to this clip, in which he uses a grape to test the new edge:

https://m.youtube.com/watch?v=ID9KZW0d9ss&ebc=ANyPxKoyX72SsCjqu911cdH_dCkEw68tPNE8oUCSzdcOran-LlZb1WqXiuKv1H4EA5q0nOhue4ImgsX__7quwMf7REhAJl26rg

[Sharpco]

The owner of the Takamura R2 just sent me the link to this clip, in which he uses a grape to test the new edge:

https://m.youtube.com/watch?v=ID9KZW0d9ss&ebc=ANyPxKoyX72SsCjqu911cdH_dCkEw68tPNE8oUCSzdcOran-LlZb1WqXiuKv1H4EA5q0nOhue4ImgsX__7quwMf7REhAJl26rg

Great. Slicing grape like that is more difficult than slicing tomato.

How long did it take with only sharpening & honing?

[kwakster]

Around half an hour, also due to the visual inspections in between passes and sharpness tests afterwards.

[kwakster]

Update on the Takamura R2 210 Gyuto:

According to the Chef this edge done on Paper Wheels lasted him 2 months in his commercial kitchen, which was just as long as the factory edge had lasted him.
During that time he sometimes touched up the edge by stropping it on an MDF strop with 1.0 micron diamond compound until that no longer worked satisfactory (in the last week or so), after which he used a fine ceramic rod on it.
Differences with the factory edge were that the Paper Wheel edge had a slightly smaller edge angle (+/- 20 degrees inclusive instead of +/- 22,5 degrees inclusive), was finer polished, and had a higher sharpness.

We're still in the process of finetuning the edge to his specific requirements, and next time he brings in the knife it will probably get a little less refined edge to see if it's useful life can be prolonged a bit more.
In his kitchen the real edge killers are the mandatory plastic cutting boards which are very abrasive on knife edges, together with the almost unavoidable tiny sand particles which sometimes remain in the huge quantities of vegetables that need to be processed.