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If it is just a scratch, I would not really bother doing anything other than using it properly, edge trailing. A small bump won't be an issue, and will get smoothed out overtime.

If there is a bit of leather that has been cut and stays raised, i'd carefully trim that off, removing as little as possible so whatever is left of the scratch gets pressed down when honing, rather than lifted and folded backwards.

Also Wootz was dedicating a lot of effort to getting the lowest BESS scores, which is an indication of how thin the apex of the edge is. But this result can be altered by sheer oxidation, not to mention a few cuts of hard vegetables on a wooden board. In his book, there is a chapter about edge retention which is not really dependent on initial sharpness but rather on apex angle.

That being said, I concur with John in making an intermediate check before honing to get a good look at the edge. The burr should be visible, but its root should be clean. If nicks appear when honing with only leather wheel and PA-70, I'm clueless. And I wouldn't use a rock hard wheel before I get satisfactory results with the leather wheel. That would eliminate a possible culprit in addition to providing a sound comparison basis.

@mrducks, do you sharpen edge leading or edge trailing ? Do you use a lot of pressure when honing ?

Hello Steve,

This overgrind in the middle is common with a lot of knife sharpening setups where you can easily spend more time sharpening the middle section than the heel and tip. It is especially pronounced on the Tormek which removes metal fast (the downside of fast sharpening). You will have to learn to focus on spending more time/pressure in those area that see the stone less often.

Do you sharpen going back and forth, or only from heel to tip ?

Also, rounding out the shoulders of the stone helps a lot.

Lastly, it is important to care about the way you lay down your knife: make sure it is not tilted towards the tip when you approach the stone. For safety's sake, I prefer to tilt it ever so slightly towards the heel.

Cheers,

Nick.

I own the KS-123, and end up more often than not using a software-based solution, even when sharpening a single or few knives at a time.

There is some friction in the KS-123 that, coupled with the flexibility of the plastic needle indicating the sharpening angle, makes for a 1 dps-ish precision. And despite the fact that Tormek wrote in their KS-123 patent that "There may be errors in computation-based solutions", I find the calculator-based process to be much more repeatable, resulting in a burr being raised in just a couple of strokes on the ungraded SG. This also minimizes the amount of metal removed, increasing the lifetime of knives (or at least the time before requiring thinning).

Also, once you get the hang of it - and , granted, with a bit of hardware for quick projection distance measuring/setting - I'm not sure the KS-123 setup is a lot faster.

All in all, I think the KS-123 has the advantage of being a reasonably accurate, self-contained solution, but calculators and calipers (and an adjustable projection distance) make for a more efficient process overall.

So this is actually a thing, even though not a Tormek thing...

Still, there are two fundamental issues with such wheels :
- If the wheel is noticeably wider than the serrations of the knife (as seems to be the case in the pictures on their website), then the result will be rounded out teeth and untouched "valleys". If the wheel is noticeably narrower than the serrations, it will be fragile *and* will cut aggressively.
- How do you restore them when they wear down ? I guess one could use diamond plates and aim for a triangular shape, but it will be fidgety.

IMO, a thin triangular or cylindrical rod used either freehand or on an edgepro-like system will make for a much more controlled process and repeatable results. Along with a flat benchstone for the backside.

This setup is always square to the usb and the grinding stone. This rig gives me one less potential outof square variable.

Yes, but it might also be a good way of making it out of round by worsening high/low spots. If you make your support long enough that you can rest the far end on a second USB, you also eliminate that risk.

Wow, a triangular wheel ? With a dual-MB102 "spaceship" contraption for truing it ? Or with a diamond-coated apex ?

Hello @Mojoman,

First of all, the nicks in the stone have nothing to do with how you set the angle. The WM-200 is a dodgy solution for setting knife angles, and if you want to "just polish", then a sharpie is a much more efficient tool, but that's beyond the point.

I think your issues come from a few things :
- You may not be holding the knife jig against the USB firmly enough. So whenever the knife starts moving a bit with the rotation of the stone, you enter the domain of static friction between the blade and stone. Then things go quickly amiss from here : the knife will move up quickly, the angle will increase quickly, and then whenever the knife is stopped again; either by your hand or by the USB or whatever, it will dig into the stone at a high angle. Had you been using the SG stone, you'd just have ruined a tiny portion of the knife edge, but not the stone. With the SJ, the stone yields first. The remedy to this is to build more experience with the SG before using the SJ stone heavily. You mentioned needing only to sharpen a little on the SJ and then strop, have you tried sharpening a little on the SG then stropping, to see if the edge is satisfactory ? Or even just honing on the leather wheel ?
- Polishing edge trailing (with the stone rotating away from the edge) avoids this issue, but creates others : a foil-like burr, slower grinding, MB-102 or FVB mandatory for controlled-angle grinding,...
- Sharp shoulders on the stone, as mentioned by Ken. However those will tend to create nicks on the shoulders themselves when laying down the knife. Rounding them out is good practice for all stones, and especially on the soft SJ to avoid chipping it when truing it.

I have a rather complex history with the SJ stone : I have been using it a lot at first, as I ordered it along with my T8, probably because I was used to sharpening with high-grit japanese benchstones. And I've been nicking it quite a bit then. Then as I got rid of the rookie mistakes such as not holding the jig properly, I also got rid of the nicks. But careful experiment showed that the assertion by Tormek that the SJ eliminated the need for honing was incorrect : the burr may not be apparent, but a tiny bit of plastified metal sits at the Apex, and it needs to be removed with about as much honing as a SG-generated burr. Also, honing with the PA-70 compound after a few light passes on the SG leaves such a good finish that I haven't felt the need for SJ-based polishing on most knives. So now I use it only occasionally, on very specific high-hardness knives where looks are somehow more important than actual edge retention in the kitchen.

And you may want to take a good look at the MB-102. It is one of those Tormek pieces of hardware that I feel should be part of a knife-sharpening kit, or a T4/8 knife sharpening edition, as they greatly increase sharpening efficiency. If you often reset angles, the KS-123 is a good tool as well.

Cheers !

Hello,

While I don't sharpen enough knives to see this phenomenon with the SB, it is my experience that this kind of issue is inherent to the Tormek principle, said otherwise it is a self-amplified phenomenon.

Sure, you don't intentionally "press harder every revolution in the same place", but think of what happens when a low spot exists for whatever reason : if you are sharpening edge leading, each time your blade will pass this low spot, it will lift ever so slightly at the incoming lip of the low spot, then dig in a bit shortly after. The result is a low spot that gets deeper with each rotation. This kind of oscillatory behavior is of course not limited to Tormek, but it is rooted in a locally favorable combination of resonant frequencies, characteristic times  (those of the tools or the operator), and gains (pressure).

I noticed this phenomenon to be especially obvious when I first toyed around with Wootz' grading technique using diamond plates. It seems I was using the perfect amount of downward pressure for the phenomenon to get noticeable quite quickly. Using less pressure helped, as did using another usb to support the far end of the diamond plate.

I don't think there is anything wrong with your SB's, I would try truing earlier (if you have to true 2-4 mm it is way too late), see if edge trailing gives satisfactory results, and also try using less pressure (I know the SB's glazed feeling makes you want to press real hard). Maybe deglaze often using a diamong plate with little pressure.

Hope this helps.

The OP  mentioned they did use the sharpie before honing as well...

I would advise using a cheap microscope to clearly see what is going on : is there any burr left (jagged apex with shiny and matte spots) ? is your sharpie removed at the apex, or at the root of the bevel ?

I don't know about the T1, but sometimes you can think there is no burr because it is no longer felt as a thin foil of metal, yet there is actually some kind of a compact layer of soft metal (the root of the burr) that is still there. One good way of telling if this is the case is to mark a spot along the edge and cut a piece of tensioned nylon wire, just by pressing the knife down at this very spot (no sawing motion at all). This is akin to what you do to measure the BESS score of your edge. If there is still some burr left, you will see a tiny nick under the microscope, the same diameter as your wire.

What I would try is honing *a lot more*, and not just until you dont feel the burr with your fingers. As for the angle, as long as you are not using way too high an angle it should be okay, make sure you are consistently hitting the edge. You should be able to tell if you're hitting the burr by the difference in sound/feel it makes when you increase the honing angle. On the T8 composite honing wheel, the difference can be felt more easily when a few drops of watere are sprinkled over the wheel before you start honing.

Good luck !

Ken,

That's interesting, I don't know the dimensions of the Tormek workstation drawers, my Tormek is on this kind of workstation.

I chose to put all knife jigs, current sharpie, current PA-70 tube, etc. in the topmost drawer. Granted, it's shallow at 60mm, but those jigs fit without issue. They are loose in the drawer, with a few separators so they don't move around too much. Even when sharpening a single knife, if it's standard thickness I tend to use my SVM rather than KG: I am used to it and the second stop of the KJ still gets in the way from time to time. So everything I need on a standard sharpening session is in this drawer, close at hand.

The second drawer holds spares and less-used tools: spare sharpies, spare paste tube, AngleMaster, stone truing tool, composite honing wheel, rust erasers, and a leather honing wheel with chromium oxide as per Wootz's idea.

Then comes the 90mm drawer which I lined with ShadowFoam and which holds my diamond plates for grading, the straight edge jig, DBS jig and related tooling, other woodworking jigs, Multibase, plus a 250mm honing wheel which I also use rather infrequently.

The other drawers are not Tormek-related : they hold various EdgePro/EdgeProLike parts for curved/serrated/awkwardly-shaped blades.

I guess your post lacks a key part information : which of your machines is standing atop it ? T7 ? T8 ? T8 black ?

Hey,

I'm not sure I understood your problem 100%, but if it can be summarized as "The bevel gets wider at the tip", it is because you are only pivoting the knife away from you, and not lifting the blade.

There are countless posts on how much to lift/pivot. In the T-4/T-8 manual, Tormek recommends to only lift the handle, not pivot. It's also shown on their basic knife sharpening video.

Gauging how much to pivot/lift according to your knife and how you clamped it is a skill you will need to learn, with the help of a sharpie. This post will tell you much of what you need to know about it. This other one is also quite interesting regarding clamping.

In a nutshell, the OP says they can't get a knife close to sharp with their T4 that came with an out-of-round wheel that they trued afterwards. I suggest more/more careful honing, preferably with a MB-102.

===

Xav,

Sans avoir le détail de ta technique il va être assez compliqué de t'aider. Notamment, quel angle choisis tu, et comment règles tu la hauteur de la barre de support ?
Ceci dit, si tu arrives à lever un morfil de chaque côté de la lame, la technique de meulage est OK, et il faut regarder du côté du démorfilage. D'expérience, la Tormek peut créer des morfils qui prennent beaucoup de temps à enlever, en particulier avec un démorfilage à main levée.

Mes deux conseils pour voir :
- Passer *beaucoup* de temps à démorfiler, et choisir l'angle en commençant avec un angle trop faible, et en allant jusqu'à sentir et entendre que la roue en cuir "gratte" sur la lame, et que des petits morceaux de déchets grisâtres se détachent (mélange de pâte à polir et de métal).
- Acheter une MB-102 si tu ne l'as pas déjà, voire un KS-123. Cela permet de contrôler l'angle de démorfilage, et d'être plus efficace sans risquer d'arrondir le tranchant en démorfilant. Démorfiler à l'angle d'affûtage + 2 degrés est un bon point de départ.

Tu peux également, si tu as une ponceuse à bande avec une bande de démorfilage, essayer de meuler sur la tormek et de démorfiler sur la ponceuse, pour confirmer que c'est bien le démorfilage à la Tormek qui est problématique.

J'espère que ça t'aidera.

As far as I am concerned, I use the SB mainly for HSS drills.

The SB works a charm for those, and I prefer it to diamond wheels because I don't have to worry about pressure (which I have a harder time adjusting with the drill jig than with the knife jig).

It does tend to glaze a bit, but the "Wootz maneuver" with a coarse diamond stone quickly restores it to a duly aggressive surface. I have only trued it once and slightly so since I own it.

Hello Philip,

In terms of tools, I would advise the following :
 - A KJ-45 knife jig
 - A KS-123 angle setter, as you mention, so wheel diameter will not be an issue
 - A USB-420 long support bar. It is not only useful for long knives, but also for medium knives where you want some leeway in terms of clamping position in the jig
 - A MB-102 that will allow you to control the angle easily when honing (or grinding edge trailing, more on that further down)
 - If you want to refine the edge, or make it coarser, two (non Tormek) diamond plates for grading the SG wheel coarse or fine, they will help grade the stone faster, while staying true longer than when using the SP-650. You will use the SE-77 tool that comes with the Tormek for this. The longer the plates the better.

Regarding heel to tip or tip to heel, definitely heel to tip. You need control when dealing with the tip and you will notice quickly that control is harder to get when you're just laying the knife down on the stone. As for the change of angle at the tip, there is no short answer : if you care about looks, you'll probably let the contact point ride up the wheel on most knives, if you want a consistent angle you will rotate the jig so the tip stays in the same place. Practice (and a sharpie) will help you chose your course of action for every knife. You won't get "six sigma", hardware-constrained repeatability for this.

Now regarding the diamond stone, I have two of them and never use them for knives. I don't like the feedback compared to the SG wheel, the scratch pattern is not as even, and they require more fussing around than the Sg stone (they are more fragile, and ACC Anticorrosion concentrate is almost mandatory). Diamond stones shine in my opinion for carbide tools or very hard steels, or when a flat grind is mandatory.

If by stropping you mean stropping on a separate leather strop after honing, it will most probably increase sharpness (if done properly) for the first few hours or the first few strokes. Only you can tell if that is important to you, I personally aim for edge retention rather than initial sharpness. And my experience is that an ungraded SG-250 followed by careful honing are the best time/performance compromise.