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I also happen to agree with you both :

• A freshly trued stone cuts more aggressively, but settles down quickly back to normal, and not in the progressive manner described by Ken.
• The more out-of-true a stone is, the faster it will get more out-of-true
• Frequent slight truings don't wear down the  stone as much as infrequent heavy truings

To maybe suggest a different wording, maybe the point Ken was making was more about "sharpening readiness" than "cutting efficiency".

I don't feel the wheel is "sharpening ready" right after it has been trued (because of too-high cutting-efficiency ) so I usually add a quick pass with a diamond plate to break down the ridges. Going **very** slowly when truing, both in terms of lowering the USB and in terms of moving the diamond tip left and right, creates shallower grooves. So the stone is closer to "sharpening-ready" afterwards.

Last, I believe that being aware about all this helps develop a technique that brings the stone out-of-true slower : use just enough pressure, use the full width of the stone, use diamond plates with 2 USBs instead of the stone grader, avoid sharpening high-carbide-content tools with a SG, be aware of the noise and water flow, etc.

As mentioned in the TT-50 topic, I believe the stone grader actually brings the stone out-of-true faster (which then requires truing).

Hmmm... I wonder what leads you to this belief?

Well, the "short" answer is : the stone grader has no reason to be held parallel to the USB. And there is no reason for the pressure applied by any hand to be equal to whatever is required to keep the stone true (or bring it closer to true) at any moment in time.

To elaborate a bit, having a human press down on the stone grader with the wheel turning is inherently an **instable** process, as whatever defects will be amplified instead of smoothed:
If the wheel has a low spot, the tool will follow the shape of the wheel and the pressure will increase when the surface of the wheel starts to rise right after the low spot. Conversely, the pressure will drop slightly shortly after the beginning of the low spot and shortly after the end of the low spot. The result will be to dig a bit into the stone at the lowest point, and grind a bit less around the high spots.

The delay in response between the cause and the effect is a perfect way to create oscillations (so called Pilot induced oscillations are an endless source of ... "interesting" situations in aviation or otherwise). Mixing oscillations and instability will not result in a nice result.

The fact that the tool is held by both hands compounds the previous phenomena by introducing variations not only along the circumference of the wheel but also between the internal and external shoulders of the wheel surface at any given point along its circumference.

This is not unique to the stone grader : if used in an uncontrolled fashion, the diamond plates may also create such undesirable effects, although holding them in the SE jig reduces the sideways variations. For a process to bring the stone closer to true (or at least no farther), you have to dampen the oscillations and bring the result closer to whatever "true" means, in this case : any point of the surface of the stone is at the same distance from the USB. The TT tool is well suited for that, the more recent version being less prone to oscillations.

I often use a diamond plate with the far end resting over a second USB, so I can both control the height precisely and grind the high spots first. Whatever flex remains in the setup (or non-parallelism between both USBs) is still a source of out-of-trueness, but it is still better overall.

Oh, and I agree 100% that sharpening brings the stone out-of-true. It does so because the edges being ground are never parallel to the USB, and they are often narrower than the wheel. I'm sure every Tormek user notices some slight variation of the noise or the water flow, that gets repeated with every turn of the wheel. That's a sure sign we're creating low spots.
Still, the steel edges are usually softer than the stone - for obvious reasons - whereas the stone grader is harder. So the latter is very good at rounding out the shoulders of the wheel, but also at bringing it out of true.

As mentioned in the TT-50 topic, I believe the stone grader actually brings the stone out-of-true faster (which then requires truing). So it seems to me its effect is somehow contrary to the truing tool (except in its ability to coarsen the grit, albeit very temporarily).

I highly recommend using the truing tool with care, and diamond plates to adjust the grit of the SG stone, as mentioned in numerous topics on this forum and as demonstrated by the late Wootz on YouTube here and here.

I'm not sure the truing tool restores the "cutting efficiency" of the stone. It's not as if the SG won't sharpen anymore if not trued for a long time. It will probably not sharpen squarely, and might create low spots on knives or planer blades and such.

The stone is more aggressive after the truing tool is used because of the temporary low grit, but that will quickly settle back to the standard average SG-250 grit. The truing tool ensures the surface of the wheel is parallel to the usb, with a constant diameter.

Sharpening technique, as well as the kind of tool getting sharpened, will have an impact on how the stone wears down, and how its geometry is impacted in the process. It will therefore require more or less frequent truing, but not because the abrasives cut less efficiently.

So I don't think it's a matter of what the average cutting efficiency is, but rather how close the wheel is to its optimal shape. Too high a pressure will exacerbate high spots and low spots, narrow tools will quickly create ridges on the stone. The sharpeners' skill (in keeping pressure optimal, using the full width of the stone, keeping tools square with the wheel, etc.) will increase the time in between two truing sessions.

Also, careful use of a diamond plate in the SE jig will keep the stone parallel to the USB for longer periods, and skill or the use of two USBs will reduce the risk of low spots.
In my experience, the use of the grading tool degrades the shape of the wheel quickly, requiring much more frequent truing. This is because it is very hard to keep it parallel to the USB (after all, why would your hands be parallel to the USB ?), and it is used roughly at constant pressure, which will tend to dig into the already low spots.

When I sharpen knives only and use diamond plates once in a while to temporarily change the grit of the SG, I barely feel the need to true at all. This increases the lifetime of the SG in the long run.

A few strokes on a belt sander do wonders for a lawnmower blade, in less time than is necessary to setup the Tormek. And the Tormek will remove metal much slower than the belt sander, especially on a thick blade.

If you're talking about Vadim's (Knife Grinders from Australia), you should take some of his videos with a grain of salt... Although his sharpening skills were unparalleled, replicating his findings has sometimes been difficult for the average Tormek user (e.g. felt wheel with CrO2 compound). And sometimes it even bordered on the esoteric, such as some hidden magic within edge calculation apps...

As a matter of personal preference, I mostly use the leather wheel although I also own the composite one. I get slightly better BESS readings with the leather wheel, but it is much messier. Given that the leather wheel and PA-70 compounds are not that expensive, you may be better off fetching those and comparing your results: Hone with composite wheel, test on paper, then hone with leather wheel, and test again.

It must have been a good test. But I didn't understand anything. The translation must have been imperfect.

The translation to what language ? @3D Anvil's message makes perfect sense...

Or it's saltpeter and you have found a cheap way to clean your aluminium tools.

The difference between the two is the resolution : Model A has a 1g resolution, Model B has a 5g resolution (not justifying the price difference from a technical standpoint but hey, that's marketing for you).

So unless you have the constraint (and means) to measure up to a 1g resolution, model B will be more than sufficient. Whether your 105 BESS are actually 107 or 103 shouldn't change your life much. Plus as you know or will discover, BESS readings are somewhat of a personal thing, and you will probably pursue consistency (are my knives roughly as sharp as I want them) rather than 2g improvements (is my knife insignificantly sharper now that I have stropped it with aged newspaper instead of a recent edition).

If your T8 is new, it might be that the rubber drive wheel is greasy and/or slick. The tray shouldn't be able to prevent the wheel from turning.

You might want to take of the honing wheel off if you have mounted it already, clean the rubber wheel with a degreaser (rubbing alcohol would work), sand it a bit with 120-grit sandpaper, and you should be good to go.

Hello Dennis,

I think it will depend what you are aiming for.

If you want a consistent 15dps edge that is sufficiently sharp and remains so for a long time, the stock SG with the honing wheel will be sufficient.

If you want a polished bevel that is very shiny and good looking, edge retention and sharpening time notwithstanding, then you may want to add the SJ to your arsenal.

However, it your used T3 doesn't come with a SJ wheel, I'd advise waiting for a few months before making sure you want to purchase one : the edge left by SG+thorough honing is very nice if not mirror-like, and the cutting performance is outstanding.

In any case, contrary to what Tormek says on the SJ webpage, the SJ does leave a burr that you'll have to remove on a honing wheel.

The next challenge is avoiding an overgrind around the first third of the blade (coming from the handle)

This overgrind is very common when learning to sharpen with the Tormek. There are two simple steps you can take to avoid this :
- round out the shoulders of the wheel (with the stone grader or a diamond plate). If the "corners" are too sharp, then they will dig into the blade as soon as you are not keeping it perfectly flat. Round shoulders are not so aggressive.
- make sure you lay down the heel of the knife on the flat portion of the wheel. The blade should be as flat as possible when laying it down, but you want to err on the safe side (that is, hitting the wheel with the heel of the blade first rather than last). If you hit the wheel with the portion of the edge that is closer to the tip, you *will* overgrind.

Hope this helps, and enjoy your Tormek !

Holy Molly.

That is so funny... "Well, if you manage to hold your steel real steady - like my friend over there is holding the camera - then your sheet of paper will yield after you apply no more than 50 pounds of force with your newly created bludgeon".

Results Oriented - Not Equipment Nor Protocol Specific

The report shows (with the caveat below) good Cutting Edge Retention ("CER") is not equipment dependent - good CER values was achieved with three different pieces of equipment. Also, KnifeGrinder's protocols are not the only way to achieve good CER. That's why on page 25, under Conclusions, I stated, "Experiment"!

The caveat is that guided sharpening (knife clamped + guide bar) achieved much higher CER values than those that did not (sharpeners PB, WK, OA, and KH). In KGA Variation #1 (page 14), half a degree angle made a noticeable difference to CER values.

I'm not sure I understand your report properly but if I do, I read that what you call "KGA Variation #1" brings CER from 399 to 391. But the standard deviation of your (small) samples are 46 and 10 respectively. So your 8mm (2%) CER variation is well within standard deviation, which is not what I'd call "noticeable".

Plus you changed the honing edge angle AND removed a step. So who is to say the difference is due to the change in angle ?

I posted somewhere else last week that I helped a commercial fisherman get his knives from around 265 BESS to around 95 BESS by deburring at .5 degree higher than the 15º angle.

You mean you had a set of similarly sharpened knives, some of which you honed for a given amount of time at 15dps, the others for the same amount of time at 15.5dps, and mean BESS was 265 on the first set and 95 on the second set ? I'm having a hard time believing that.

I guess what I'm saying is that to quantify the influence of .5dps difference in honing edge angle is in itself a very ambitious endeavor : your K09-K18 sample already already comes out of the factory with initial BESS readings from 125 to 170. And how many BESS readings did you take per knife ? BESS scores vary between the flat part and the curved part of the blade because the angle changes due to the operator's combination of pivoting and lifting in the curved area, close to the tip.
You would also have to make sure that all knives come out of the sharpening step with consistent sets of BESS readings, and randomize the order in which you take them over the honing wheel to factor out potential wear of said wheel over a significant set of knives. Along with many other precautions to make sure the operator doesn't know if they are honing @15 or 15.5 dps. This would prove very costly in time and money, but I don't see many other ways to quantify the effect of the .5dps difference.

If just a small process difference proves that hard to evaluate, then the influence of an entire process is orders of magnitude harder, and in the end I think one has to take even Wootz' litterature as a very interesting informed experiment but not a rock-hard scientific conclusion. The influence of the operator in itself is tremendous.

Again, the only conclusion I risk making based on your report is that I'd rather have my knives sharpened by you and your equipment than by your fellow sharpener and their equipment. And you can't increase the significance of your results by "bunching up" results of completely different experiments because you don't control the variations.

Still, a quick double check with Tormek support (support@tormek.se) cannot hurt, right ?

They've probably run into this problem already so...