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If your blade is still usable, shape-wise, after having lost 8 mm of height, then two things :
- you don't *have to* remove these layers if the blade is still thin enough, they will sharpen easily and the cutting will still be done by the hard steel
- if the blade is significantly thicker at this point, you have to thin it exactly the same way you'd do with any knife : grind it at a shallow angle till you have a "zero edge" (little to no bevel due to the thinness of the blade) then sharpen it at your usual angle.

How shallow of an angle you want is a matter for discussion. As a rule, you want it significantly below your sharpening angle, but still significantly higher than the base angle of the blade from spine to original edge. So if, say, your base angle is 1dps, and your usual sharpening angle is 15dps, 3 to 4 dps is a safe bet.

Your base angle is arcsin(spine_thickness/(2*original_blade_height)). Also, please note that this will take time on a Tormek, and must not be rushed.

 

It looks like a crude vise jig for sharpening chisels & plan irons on bench stones / diamond plates.

So, any luck with this ?

I agree with Rich. In my experience, the Tormek leather wheel + PA70 compound is the best efficiency / edge retention compromise.

I'm not sure what a high speed honing device would achieve that the leather wheel cannot, plus the risk of overheating or messing up the edge seems not worth the hassle.

It may be that this is the result of the T1 being a constant angle sharpener : as you near the apex, the grinding angle remains constant while the blade geometry usually changes (the most common is : it gets thicker behind the edge). Santokus should be less prone to this issue than standard, upward-curving european chef knives.

Usually, to maintain a constant bevel at the tip, such knives are sharpened at a higher angle near the tip. This way, the bevel width remains constant. Constant angle sharpeners will maintain a constant angle, so you will need to remove more material to get to the apex. Said otherwise, you will have to sharpen the shoulders of the bevel first, before you gradually move down to the apex.

You can confirm that hypothesis with the sharpie : apply it in such a manner that is extends beyond the edge onto the blade, and watch carefully after a full pass : if the ink is removed right where the bevel meets the flat of the blade, you have your answer. And with a constant angle sharpener there is just one way to do it : keep on grinding. Your bevel will widen but there is no alternative.

I don't remove it. Every once in a while, I just turn it a bit so the EZYlock nut untightens a bit, and leave it there. Then retighten the nut with the label facing upward for the next session.

I test every knife with a Bess Tester, my results are the same whether I measure or use the KS-123.  If you use the same care setting up the KS-123 as you do measuring, I would, with confidence state, you could possibly be more accurate using it.

Whatever the real accuracy of the KS-123, I think it is good enough that you won't be able to tell the results apart by BESS testing. +/- 1dps won't have any significant impact on sharpness. If you follow this train of thought, even the AngleMaster or a plain protractor will get you very sharp knives. Initial sharpness depends more on technique than absolute edge angle measured with a .1 dps precision.

+/- 1 dps will have a significant impact on metal removal though, so the real question is : "is the KS-123 consistent enough that I can get very very close to the angle I used the previous time ?" I can't, but I have stopped using the KS-123 more than very occasionally. On my everyday knives, which I sharpen the most, measuring usually gets me a burr on the first pass, second pass at worst. Most of my time is spent honing the burr away.

As to the KS-123 being *more accurate* than measuring, evidence would further this theory more than confidence.

You can use the diamond stones, they are easier to use than the stone grader. Is you have the straight edge jig, backthese cards with anything thick and you're set.

300 will not give your the roughest grit though, I use 80 and the SG is quite aggressive afterwards.

If you're sharepning a knife with a thick blade, you might be reprofiling it even if the sharpie test comes out okayish. So you'll have to remove a lot of material before consistently hitting the APEX, which the T1 is not good at. It may require thinning the knife with a more suitable device beforehand. This is compounded with hard steels.

The belt grinder will always come in handy when you will want to regrind the bolsters of the german knives (I assume they do have a bolster guard like many Wusthofs/Zwillings/...). Bolsters are a PITA, whatever the sharpening system, if we want to keep a sharp knife for generations.

The T1 should do a good job of keeping those sharp as long as it is used for short, frequent sessions. I'd say a couple passes on each side and a thorough honing on a slightly wet composite wheel.

Hi Adrian, and welcome to the Forum.

TL/DR: The T1 is only for quick touchups of western-bladed, no-too-dull knives.

Uncut (^^) version :

Although the T1 has a diamond stone, it is not intended for heavy reprofiling. Forum members usually follow a couple different methods on T4/T8-type machines : either grade the stone very coarse or use it just after truing, ore use after-market ultra-low-grit CBN wheels, or even Norton coarse bench grinder wheels. Those are not options for the T1, and only the last two will work on super steels.
For heavy reprofiling, many members use belt grinders for heavy-duty work, then finish up on the Tormek.

So the T1 being slow is normal, especially on super steels which will wear down more slowly than standard steels. Also keep in mind that super steels can form a very tiny - yet quite hard - burr. These need to be honed thoroughly, and this will again take longer than standard steels.

I don't own a T1, but regarding your single-beveled knives :
- Yanagibas, like usubas, takohikis and debas are those thick,single-beveled, japanese kitchen knives (also called wa-bocho, wa standing for Japan). They cannot be sharpened on a T1 (not on any other Tormek for that matter) as it will ruin the grind. The bevel is flat/very-slightly convex and the Tormek will make it concave. The bevel is to be sharpened along its entire height and the Tormek will only sharpen a tiny bit at a time. The hollow, u-shaped back (ura) is to be sharpened flat so the top and bottom get equally sharpened. And I won't even talk about what happens at the tip (kissaki). Thoses knives must be sharpened on flat media, preferably the traditional way : using flat benchstones. So if your knife actually is a yanagiba, keep away from the T1.
- If by yanagiba you actually meant a sujihiki (also called laser), this is a western-bladed japanese knife (also called "yo-bocho"). There should therefore be no problem sharpening it on a Tormek, and if it is highly assymetrical as sometimes is the case, then sharpen it very assymetrically, but I'm not sure it applies for your knife.

Also a common problem with Tormeks (it is a bit different though on T1/T2 compared to T4/T8) is having trouble with bolsters.
Depending on the shape of the bolster/handle, it may not be doable to sharpen a knife close to the handle. Victorinox swibos are infamously known for this : as the handle is made of plastic, the only way you can sharpen it close to the handle is by heavily (and messily) grinding the plastic away.
This is especially true for
this kind of knife which, if you look closely is not factory sharpened close to the handle. However, as you sharpen it on a Tormek, you will create a dent at that point where you can no longer get closer to the handle, and this will be an issue for some cuts. Again, a belt grinder is the solution.

I cannot talk to chinese cleavers on a T1 as I own neither. Hope this helps !

 

I would try sharpening one knife using a distance-based angle setting method, then checking it with the laser goniometer, so you can actually incriminate the KS-123 or put the blame on your goniometer.

Also, have you tried lubricating the surface where the black plastic scale contacts the metal body of the KS-123 ? This helps reduce hysteresis.

I agree with the PETG suggestion. There are even some not-so-expensive low-friction ones.

I was not really afraid of having to print additional ones (I usually print a couple anyway, just in case). I was rather thinking of tiny plastic particles getting inside the bearings...

Rick, it's a nice idea. My first thought was "let's print it with a Igus filament", although buying a roll just for one washer may slightly impair the financial equation

Quick question : Aren't your concerned with the plastic washer wearing down with time ?