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This will lead to the same result. You will have to add a  constant offset onto the measured values if you use the stock calculator's formulae.

Maybe this is a better idea, because it uses the known method of measuring from the cutting edge to a stop with a ruler.

I never payed attention to this part of the forum so I was not aware of all that. Anyways, the pudding seems eaten and proven.

I never used TormekCalc because it does not run with alternative spreadsheet programs.
I am glad it worked out for Perra's program (Angle Calculator Lite). I like to keep things as complicated as necessary and as simple as possible.

The wheel is that diameter.

Thank you for the link.
I looked at JVH's drawings and the drawings suggests that he determines the offset in the projection plane by referencing the center of the USB, while Rich's drawing clearly references a point on the rear of the USB, which is where the "stop screw plane", as I called it meets the USB. The difference will be 6 mm.

Dutchman's drawing too seem to reference the center of the USB, so I guess Rich's drawing, which I used as a reference, uses a different reference point. Can somebody chime in and clear this up?

You're right about the "Constant Offset" (I use 30.1mm)

In Dutchman's original work, measurements were made to the rear of the USB.  When he wrote the "More math..." booklet, the measurements were "mathematically moved" (my phrase) to the USB center, the formula is run, then the answer is "moved" back to the rear.  Difference isn't much in most cases... just made it work better for other than its original intent.  Both booklets can be found in Dutchman's post, for those that are interested.

[line through the center of the spine]

I have recently sharpened the blade of a metal hand planer, which is a look-a-like of a Stanley single iron bench plane SB3 (just to make clear what I talk about). The blades are hardened (HSS), so the standard SG stone will take hours. I used a F120 corundum stone for the coarse work and a SiC stone to make it finer.

Since chisels and similar blades have a flat upper surface, the WM-200 angle tool works fine for that. The recommended grinding angles for those blades are between 20-30 dps (although there is only one side to be sharpened). The blade itself is angled at about 45° from the working surface, which leaves several degrees of relief behind the cutting edge. In my case the bevel is down.

Spoiled by sharpening by numbers, I looked if setting the angle by T-USB was feasible, which would allow for grinding and honing at a precise angle, just as it is customary todays for knives.

All associated programs ask for the jig diameter. They were obviously developed with knife sharpening in mind, so they silently assume a symmetrically round jig (at the spot where it rests on the USB at least). All past knife jigs fulfil this demand, and the diameter was chosen for simplicity and convenience.
The real value of interest however, is the distance from T-USB to the imaginary center plane that is constructed by the line through the center of the spine (of a knife) and the cutting edge (let´s call this the center plane for the lack of better words).

This is the parameter the program works with, because this distance is a crucial part in constructing the triangle that spits out the T-USB-to-stone value we are after; on a standard knife jig it comes out as 12 mm / 2 = 6 mm.
The graph here Calculations used for calculating SVM Knife Projection displays those relations quite nicely.

But note, this is a source of error: the older models of the knife jig used to have a 12 mm metal bar and thus a consistent diameter throughout. They had the potential of non-symmetric clamping, which would lead to uneven bevels. Its current successor was made symmetric, but has an inherently variable bar size due to its construction. Using it at the outmost rest will indeed yield 12 mm, but on the inner rest, for smaller knives, it will be more like 14 mm. This introduces an error probably overseen by many.

Fortunately sharpening of knives is not rocket science, a fraction of a degree up or down won´t hurt as long as the settings are consistent, repeatable and symmetric, but keep that source of error in mind particularly if you are the nit-picking type.

I used the SE-77 square edge jig (in case this has changed over the years: I speak of the model ca. 2007) as a test candidate. The parameters needed for the program(s) are not obvious or readily measurable, so I looked into that.

The first parameter to determine is jig diameter. As mentioned before, the internally used value is the distance from T-USB to the center plane. In our case, the latter coincides with the top of the blade (there is no second blade side and there is no upper half of the jig rod). Consequently the choice for naming this parameter "jig diameter" turns out to be an unhappy one, but that´s how it evolved. Let´s call this real parameter center plane displacement for the exercise.

For the SE-77 square edge jig center plane displacement comes out as 24.5 mm (see fig.1 "measuring center plane displacement"; measure the distance from the top of the blade to T-USB using a vernier). This is straightforward. This number is invariable and only needs to be determined once for a given jig.

According to the above explanations, this is only half of what the jig diameter parameter expects despite the fact that it internally works with exactly that number, so you have to enter double of that value, i.e. 49 mm. (Being taken for granted, this parameter accordingly does not receive particular attention in the above drawing. It is denoted by a circle around the cross-section of the USB.)

One more measurement we need is projection. Projection is defined as the distance between the point where the center plane meets the stone and a plane that is in a 90° angle to it that touches the USB bar at the stop screw (let´s call this stop screw plane, see picture). This is a bit tricky to measure. (Note that neither the jig axle's rest nor the jig stop's contact point are necessarily meeting T-USB. They are different points, but close. Refer to above mentioned graph). Thus directly measuring the distance from the USB's rear side to the cutting edge in parallel to the center plane with a vernier is not yielding the right result , since the SE-77's flanges protrude towards the operator and obstruct any direct access to the USB with the caliper's feeler fingers.

See fig. 2 "measuring stop screw plane to rear jig offset". Place a try square flush to the top of the jig. (Left or right of the stone the jig can be flipped forward or backward and stay put in a resting position). Its one leg is in parallel to the center plane. Measure the distance from the inner edge of the other leg to the USB with the vernier.

It turns out that this offset is exactly 5.5 mm. (Again, measured on my older jig). The intermediate projection value measured with the caliper was 70 mm (See fig. 3 "measuring the intermediate projection value": use your vernier to measure the distance from the cutting edge to the rear side of the jig. Aim to be in parallel to the center plane), so the correct projection is 70-5.5 = 64 mm rounded.

I chose to grind at 27.5 dps, and the T-USB value produced by the program is 26 mm (rounded) (note: this is only valid in conjunction with the current diameter of my wheel), which is much smaller (about factor 3) than what one may expect for knives due to the much smaller projection.

I sharpened with this value, and after sharpening I checked the edge against the angle gauge notches on the WM-200 (fig.4: "controlling the final angle"); it fits perfectly into (one half) of the 55° notch. So this is another proof that the number method works universally.

A small appliance akin to the ones existing for knives could be made to mount the planer blade at a certain projection every time, in which case one could work with the very same setting over and over until the wheel diameter has changed. Even thicker or thinner blades would not make a difference, since the jig opens towards the bottom.

I later sharpened a plain chisel with the same method. Without going into detail (since the basic procedure is well documented), the angle turns out correct.

Have fun.

Looks good!  There's a calculator for the SE-77 in Calcapp (under "Other Jigs/Tools") if you want to check the results.  (Projection distance is measured from the front of the jig to the edge of the chisel)...

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There's also a calculator in jvh's "TormekCalc" spreadsheet.

I didn't check your results... since you didn't say what the Wheel Diameter was, (or if you did I missed it), but if it's around 190mm, then we're in the ballpark. 

You may also find this thread of interest...

SE-77 & TTS-100

... in particular jvh's diagrams which (I believe) confirm your measurements.

I am new to the Tormek world. I don't want to be the irritating newbie who asks that the group repeat the basics just for me. So, started with the pinned post "Tips, Tricks & Techniques Beginners Start Here" (dated March 2013).  link sharptoolsusa.com seems inactive.  Tormek has a YouTube series "Tormek Live Sharpening" which might be nice to binge watch—if I could find a complete listing (can't find this on tormek.com). Any help find these would be great. Then I will, I promise, go away and leave you all in peace until I have done my homework—and have sharpened a bunch of stuff on my Tormek.

Sharptools is now Advanced Machinery

The Tormek Sharpening classes from the live streams is HERE.

Sono relativamente nuovo sia per il forum che per quanto riguarda l'utilizzazione del sistema Tormek.
la prima domanda che faccio è come facilmente vi aspettate è sull'angolo di affilatura . Non solo perché  sembra una lotteria, ognuno da i propri gradi; manca una tabella che dia dei valori di massima dai quali partire es: coltelli da cucina generici, da prosciutto, da Bushcraft ecc ma soprattutto dire se i gradi si riferiscono solo ad un lato o tutti e due. ES: cucina 20° , sono totali, o 20 °  per ogni faccia,  ? Seconda domanda: spesso i coltelli sono molto rovinati e occorre lavorare  ore per ristabilire la forma. Si , mi direte che esistono le diamantate, ma queste non solo costano moltissimo, ma soprattutto si consumano facilmente. Quindi: è prevista l'uscita di una mola di pietra molto ruvida da poter facilmente, in poco tempo, ristabilire la forma originale di una lama?

For reference, this is what it translated to:

I am relatively new to both the forum and the use of the Tormek system.
The first question I ask is how easily you expect is about the sharpening angle. Not just because it looks like a lottery, everyone gives their own ranks; there is no table that gives general values from which to start e.g.: generic kitchen knives, ham knives, Bushcraft knives etc. but above all to say if the grades refer only to one side or both. ES: kitchen 20°, are total, or 20° for each face, ? Second question: knives are often very damaged and you have to work for hours to restore the shape. Yes, you will tell me that there are diamonds, but these not only cost a lot, but above all they wear out easily. So: is it planned to come out with a very rough stone wheel that can easily, in a short time, restore the original shape of a blade?

To answer some of it... angles given in your example are for each side, so 20 deg. per side, 40 deg. total. 

There's no set rule on what angle to use, although there are examples in the Tormek manual. One idea is to match what is on the knife for a starting point, then work from there.

There are some members who use a more coarse stone... I'll let them comment.  But if you need to make a repair with the stone you have, try grinding at a very high angle until you repair the damage, then lower the angle and sharpen.  This will make the work take less time.

Hope that helps.

Can you please post a link to this video?
For some reason, I cant open this.
Thanks

https://youtu.be/Y4ReQ83CZOQ

So this is a link to some pics I took.

I put the knife into the jig as i normally would and turned the first screw followed by the black one (took care not to over tighten anything)

I took a look at the jig and noticed that it was not parallel.

Steel thickness is 5/32 and the blade is 3.5" in length

Wonder if this may be causing the issue.

https://www.reddit.com/user/_WOLF_2434/comments/18zj44x/kj45/

Yeah, you need to loosen the front screw so you can make the clamp more parallel.  It should conform to the sides of the knife.

More like this...

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vs. yours...

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If the blade tapers from spine to edge, then the clamp should match that also.

Here's a good example of why I use (and recommend) a ceramic rod vs. a honing steel...

(Also some good info on burrs.)

In addition to the above, you might also watch the video Tormek did on the KJ-45...

... it shows some tips on clamping the blade.

How far off is the angle when you check the other side?

Hi, I'm trying to download the amazing calc but requires password, and i've been trying to send a pm but there must be some failure in the forum, i tried with 3 navigators and the same result. Is there any way to get it?.

Thanks and happy new year.

I was able to send a PM, so I let him know.

Here is a link to the Tips online class (#8), one of the classes where releasing the EZYlock is demonstrated, starting at 14:45.

Ken

Link

 

...
Of course, the jig relies on the support arm being at a fixed height relative to the grinding wheel and I find the TTS-100 turning tool setter works best for this. 

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Pretty cool.

Calcapp (as well as jvh's TormekCalc) has a calculator that can be used to set the USB (support arm).  For example...

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Would work well with your setup, (as an alternative to the TTS-100).

I have a question about the felt deburring.
I use the rock hard felt wheel at .65 density from piriui polishing in China loaded with a 1 micron diamond paste which I'm not sure is penetrating into the felt. I deburr 3 passes lightly at +2 dps setting the angle with the cal cap calculator.
after high angle honing the bess score is consistently at 160 to 145 bess.
Does this mean the wire burr has not been removed properly and if thats the case what can I do to improve the process?

I'm guessing you're using info from the "Knife Deburring" book?  Depending on the steel, that book says that after deburring on felt you'll get a BESS score of about 150.  You then need to finish on a strop, paper wheel, or leather wheel to remove the "foil edge". (p.40)

So, I guess give one of those a try? 

I have never tried this but I wonder. Regarding the off center sharpening of the older Tormek knife jigs. As some of you know, some Japanese knives are sharpened on one side only. Would that make the older jigs useful since they "prefer" one side over the other?

If there's an advantage, I don't see it.  You'd still have to match the angle on the one side, and it wouldn't match anything on the other side that I can see anyway...

...
I do have the very occasional need to follow a curved edge on a knife. Boning knife or kukri for example. These are concave curves and cannot be followed (by me anyway) on a square edge stone. The edge just ruins the curve. The Tormek stones are sharp edged and would just grind up these curves.
...

Tormek did a live class on this:

The "secret" is to round the edge of the wheel, as seen starting here...

Sharpen Recurved Blades | Part 17 | Tormek Live Sharpening Class... 7:49

Greetings, looking for some direction. I am a new owner of a T8. I am having issues with the grind angle not being the same on each side of the blade. What am I doing wrong? Thank you in advance.

See if this recent thread helps:  Asymmetrical bevel result on knives