Wire Edge Prevention

[KnifeGrinders]

Mike's comment inspired additional experiments.

We know that the base burr adjacent to the apex is more difficult to remove than the outer layers of the burr.
Leather, balsa, felt, paper wheel and linen or cotton strops used in deburring are not equal - not every blade can be “de-wired” on all of the abovementioned substrates.

By aggressiveness we group them in 3 groups:
linen/cotton, paper wheels and balsa;
next comes leather;
and the most aggressive is felt which works well for both super-steels and those deburring headache stainless steels at the low end (jewelers use felt as the base for polishing their gems for a reason).

But this grouping is experience-based and rather intuitive, so we decided to check it experimentally.

The same WiltShire stainless steel kitchen knife had edge set at 13 dps on #1000 CBN, then honed at the edge angle on a Paper Wheel with 5-micron diamonds to thin away the burr - the result is a flimsy feather burr that you cannot feel and can hardly see under the right light.

From here we did it differently.
In the 1st round we honed it on Tormek on a paper wheel with 1-micron diamonds (using a bushing to fit the shaft).
In the 2nd round we honed it on Tormek leather wheel with 1-micron diamonds.
In the 3rd round we honed it on Tormek on the felt wheel with 1-micron diamonds.

In all cases we honed the knife at 15 dps, i.e. at 2 degree higher than the edge angle - that in the previous experiments has shown the best "de-wiring" effect. The honing angle was controlled using our Frontal Vertical Base for honing away from the wheel and computer software.

Tormek - Paper Wheel

After the 5-micron paper wheel the feather burr scored 215 BESS;
After Tormek with 1-micron paper wheel 120 BESS.

Tormek - Leather Wheel

After the 5-micron paper wheel the feather burr scored 285 BESS;
After Tormek with 1-micron leather wheel 100 BESS.

Tormek - Felt Wheel

After the 5-micron paper wheel the feather burr scored 255 BESS;
After Tormek with 1-micron felt wheel 80 BESS.

As you can see, the resulting BESS scores confirm our a priori grouping of the honing base substrates.
In the context of these tests, the lower BESS score indicates the better deburring, and the felt shows the best "de-wiring" of all, i.e. the best removal of the base burr; leather follows, and paper as the finest substrate shows the worse score.

***

From the above findings one could make a logical conclusion that the final cleanup of the edge on the fine paper wheel might give somewhat better sharpness than finishing on the leather wheel.
We tested this as well.
The knife deburred on the felt wheel as described above, we finished differently:
- on a paper wheel with CHROMOX at 1400 RPM; versus
- on a Tormek leather wheel with CHROMOX at 90 RPM.

Final cleanup on a paper wheel with CHROMOX

55-65 BESS

Final cleanup on the Tormek leather wheel with CHROMOX

85 BESS (i.e no sharpness improvement over the preceding felt honing)

***
Well, we've got an experimental proof of what already know - that the edge you get depends on both the honing compound and the substrate this compound is on.
Felt is not a panacea though, neither is a paper wheel - for a given class of steels there is its own best combination of the honing compound, substrate, honing angle and amount of honing.
The practical takeaway of this series of experiments is that now we know how to get a sharp and strong edge on those lower-end stainless steel knives.