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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...

I have tried the felt wheel but I gave up after 10+ uses. In the best cases I could see an insignificant improvement from the leather honing wheel (high hardness steel), and in most cases I saw the BESS score worsen. It is not statistically significant, though, and maybe I woudl have gotten better over time.

One word of caution though... There probably is a reason Tormek didn't make a 250mm honing wheel : it would get in the way when sharpening long knives. So you'll have to take your honing wheel off

What a big whole lot of AI slop.

That's a very interesting subject, thanks !

It incidentally explains also why many of the MagnaCut knives were sold out everywhere (and why there weren't many). Hopefully we will be able to see (and sharpen) MagnaMax chef knives.

Thanks for sharing these results !

I read the report, which is very informative and detailed.

A few comments/questions, if I may :

First, there are many differences between the compared methods. The way I was taught, you have to make sure only one parameter varies when you want to make a comparison between two methods, and you have to have statistically significant samples. If I understood properly, you could very well have chosen the following titles for your report :
"Controlled Angle yields superior CER compared to Freehand" (which we have to say kinda makes sense) or if we wanna get cheeky :
"Round sharpening and honing medium yield superior CER compared to flat ones" or even :
"Eric Ho gets better CER than other sharpeners"  .
The huge difference in methods may only allow to increase confidence that "better sharpeners get better BESS *and* ICP", rather than infer a second-order polynomial relationship between BESS and ICP. There are mainly four clusters, you have a high chance of being able to fit those rather well with a second degree polynomial. It would also be true if you plotted BESS score vs age of sharpener.
[EDIT]Wootz and L. Thomas seem to agree on an empirical formula that ties edge retention to hardness/composition of the steel and edge angle only, which would imply ER only depends on BESS scores to the extent that higher wear-resistance steels allow for better initial sharpness. Also, a basic razor blade has very low BESS, but low wear resistance and poor edge retention.[/EDIT]

More seriously, if we look at the graph on page 20, but only take your results into account... Why can't we conclude "better BESS scores yield worse ICP overall" ?  That would be consistent with what several sharpeners have reported, when polishing the edge. I tried to guess the ICP/BESS values from your graph to put it inside an Excel spreadsheet and look at the global tendency, as shown on the attached image. That can only be proven true or false (or unrelated) by having a bigger sample and controlled variation of experimental parameters.
I understand it is a very complex thing to do, but changing so many things between two subsets makes it hard to draw any conclusion.

More on the "controlled angle" part. Wootz and Larrin Thomas concluded that angle was by far the most important factor in edge retention. So it would seem natural that methods that yield lower edge angle spread also yield better CER. That would also seem consistent with the fact that Wootz himself seemed to hint that others methods work well, without the whole paper wheel buffing shebang. But what about the Tormek protocol : grind using SG, hone using leather ? What BESS for what CER, when done by Eric Ho ?

A word on the Ken Onion WorkSharp : I own it as well as the T8, and am by no means a professional sharpener. I set it up with a FVB so I can better control the angle. While I consistently get 100-110 BESS @15dps using a simple protocol on the T8, I usually get 120-140 BESS with the WorkSharp with the fine belt followed by honing on a leather belt with Tormek compound. So a professional sharpener being satisfied with 250 BESS leaves me... flabbergasted. Side note : I only use it on lowest speed unless I need to grind a bolster.

Hope this helps with this edge retention topic, which I believe is indeed key to knives sharpening.

Nick.

Rich, this is a very nice and useful piece of work. Thanks a lot for sharing !

I was wondering, are you familiar with heat set inserts ? They are inexpensive and make for a very easy way to add strong threads to 3D-printed parts. All you have to do is :
- change the diameter of the hole to the appropriate one for the thread size (3.8 mm for a M3 insert for instance, and some even go as far as making a conical insert to minimize bulgin around the insertion point)
- put these holes inside a cylinder-shaped modifier so that the wall thickness around the insert is about 80% of the thread size (3.2mm at least for M4 for instance),
- add them using a soldering iron (any will do but using the included toolheads will make it even easier).

A nice trick is to put them on the backside if you can so that the screw tends to pull the insert into the 3D printed part instead of ripping it out. You can add the modifiers as separate bodies in F3D so they will be appropriately placed in your slicer. I can make the modification for you in your design if you wish.

Many thanks,

Nick.

@kwakster, the quality of your work is amazing. Thanks for sharing those with us. I love the new look of the handle.

If sub 200 Bess is your goal then sell out and do all your sharpening on belt grinders and go for volume rather than quality.

I found that controlled angle grinding on a belt grinder followed by controlled honing on leather belt+PA70 compound yield 120ish BESS results. I don't think speed and quality are exclusive, and when reprofiling in involved, this is clearly the way to go. The Tormek has an edge in dust generation and "zen" power, plus it shines when it is not exclusively used for sharpening knives.

Just as those who sharpen  knives exclusively occasionally complain about having  to pay for including the SE-77 with the T8, woodworkers might complain about paying to include a US-430.

I was not suggesting including an **additional** US-430 that would sit in a drawer for those working only wood, but rather including it as standard delivery.
As far as I know, it is not a hindrance for those who wouldn't use the additional length. Regarding manufacturing costs, I doubt an additional welding and a few grams of steel would make much of a difference (plus the US-430 only uses straight bars).