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So if I understand correctly you're measuring 90mm TUSB on the first picture ?

No. The ruler displays the true distance from the outmost point of the 12mm rod. If the ruler is correctly aimed towards the hub, then this coincides with T-USB.

So what you are interested in is where the wheel´s apex aligns with the ruler. Since the markings are on the side of the ruler and the apex is in its center (and thus obscured by the ruler), the red "slider" always displays the correct value of the apex - on the bottom side of the red thing.

In the picture the value will be close to 11. This is of course a non-realistic setting chosen to demonstrate the principle.

I'm wondering whether a version with a slightly wider red cube and two ball bearings would make it even easier to use ?

You mean to achieve a perpendicular alignment of the ruler, sort of auto-alignment?
This would work, but I suspect only for a certain wheel diameter, caused by the fixed distance of the rollers. In all other cases, the red cube would either not go down far enough or the rollers would dangle in the air. If you find a fix for that, let us know.

Some kind of a rubber-band towards the hub would do the same, if desired.
In both cases the 12mm bore would need to be rather loose.
I don´t know if the effort pays.

Attached is a picture of a bare bone usage. The red cube is not strictly needed, but the way the scale is marked introduces a bit of guesswork as to what the apex reads.

On the second picture the red cube has been rotated 180°. The nose has no function other than being in the way in this usage. The arrows clearly show the nearly 2mm of difference between the reading where the stone´s circumference meets the ruler and the apex reading. Naturally, this is worst on the small wheel.

Perra,

I just stumbled over a thing...

All T-USB calculation hinges on the fact that the projection line goes (ideally) exactly through the center of the (knife-) jig.

With the T-Cube, the real projection line is offset of the ideal projection line by 1mm up, which is comprised by the thickness of the ruler blade.

I have addressed the offset error above (although we were speaking of amounts 10x higher), and it goes back to Dutchman´s printed manuals.

You were trying to compensate for the offset by introducing the 6mm ridge which adds to the USB, but in combination with the ruler this effects to 7mm.

You could make the ridge smaller by a millimeter, resulting in a total offset of 5+1 mm, but that would not cure the problem down where the ruler meets the stone.

I don´t know how large the error will be in degrees, but there is an error. The digital unit will be insensitive to that, but the anglemaster will show false values. All measurements thereof have to be referred to the exact point where the edge meets the stone and not 1mm higher. You could however grind a sharp edge on the ruler...

Let me know if I am wrong. This may well be.

FYI.
This is a very easy jig that lets me precisely set a certain angle by adjusting the distance from the top of the USB bar to the wheel (hereabouts known as "T-USB" - hence the name), according to the output of any of the simple, but most potent calculators provided here.

It can be realized easily without specialized tools, although a 3D-printer is pure luxury.

You could however make the same thing using a piece of hard wood or plastic or similar, with little more effort.

The idea is based on Perra´s T-Cube, and indeed this unit can be put to good use together with the described jig.

I found that the T-Cube probably excels at using a digital inclination measuring device, and while it may have several other uses (probably not discovered yet), it is not optimal for setting T-USB. If you use it like depicted by resting the bracket on the back side against the USB as shown in pic7, then a (possibly small) error is introduced by measuring the distance at the side of the USB (introducing an offset of 6mm from the USB´s centerline) down to the stone´s perimeter (T-USB is specified as the top of the USB to the stone measured through the USB´s center). Apart from this, one hand is blocked by having to hold onto the jig. The next question is, where does the ruler touch the stone.

So I realized that the ruler should really be 90° rotated and start with "0" flush with the USB´s top down.

I borrowed the mounting of the ruler from Perra´s T-Cube; a slot and a screw. Differently however, the ruler is not intended to ever move in there. This is just a convenient receptacle. The ruler has its last > 12mm sawn off, so that it fits into the fixture. Its length is designed in a way that the ruler, inserted to 5,0 cm, displays the exact distance from top of USB. There is no magic to that number, it could be made shorter, but I found T-USB numbers below 7cm useless.
I chopped the ruler off at 15cm, which promises a great span of projection distance vs. wheel diameter vs. angles.

The earlier printed T-Cube can be made to reside on top of the wheel to the side loosely, so that it rides up and down with gravity when changing the USB´s height, giving the exact reading on its edge.

Thanks to a snug fit of the 12mm bore the jig stays put in any position. Should this joint eventually become loose by frequent usage, a screw could be incorporated like the one that is there.

The ruler of course has to point perfectly towards the center of the wheel, and once you are close to the final destination, this should be re-checked. You could alternatively (as already adressed somewhere) use a rubber band around the wheel hub towards the ruler to center it automatically.

The reading you make on the moving part´s edge is then always guaranteed to refer to the wheel´s apex.

My friend is an expert to 3D printing (you would think this were a sunday afternoon walk for him, watching him). He says even a M8 nut is lousy to print on a 3D printer and of doubtful longevity, so he inserts a slot for a metal M8 nut as depicted in the detail picture. Brilliant.

Hope this is of use for somebody.
-Helmut

With "ruining" I was probably over-egging the pudding. Their sharpness was less high than my disappointment.

f one knife was not turning out as expected, why would one proceed with other knives before correcting the situation?

Way back then (probably ten years ago) I did not have knowledge of all that great information (like setting the t-usb and all that) and all I had was the anglemaster - and I was obviously misunderstanding the information on how to use it, letting alone that it does not work well on knives from a start.

So it was quite obvious, that something was wrong, unfortunately there was no clue as to what.
So how can one possibly correct something that was not knowingly recognized as wrong, and not knowing of any other path to pursue?

As I said above, the manual should clearly explain the mechanism and the do´s and don´ts. Maybe it does today, but it didn´t back then. It is not enough to show a picture, which you can mis-interpret, you have to understand why.

I am a teacher, and preparing learning material is my daily work. People have to unterstand the underlying mechanisms and not mindlessly repeat a sermon, or they will never be able to react to an unforeseen deviation from the manual.

I have, after intensive study of this all, found a way to get my knives sharp, but this is not something you can automatically expect from somebody buying such a high-priced solution unbiased.

Short and concise.

I wish I had this information before I ruined all those knives.

I think it would work if you used an aluminum plate instead of the phenolic plate.

The phenolic plate appears very rigid, given its thickness of 10mm.

The thickness appeared appropriate because of:

So we want the platform as thin as we can get it, but not so thin that knife handles hit the US or the scissors jig base.

If I could get a slab of aluminum about 3/8" or 1/2" I'd be very happy. 

Aluminium was the first thing that came to mind, but I thought why be perfectionistic for something that may have to be revised anyway...

Looks like the knurled knobs will block use of anything very wide or that needs to extend beyond the back/top of the platform.  I would dispense with the knurled knobs in favor of flathead screws which would produce a fully flat platform surface, such as pictured below.

Yes indeed, this would eventually have arisen. The above design is unfinished and just meant to demonstrate the principle.

The picture you are posting: is this your rendering of a HK-50?
If yes, it appears to me that the jig is mounted 180° reversed on the platform. As Herman states here the HK-50 should be as close to the USB as possible, as depicted in this posting. In other words: the jig´s flange should protrude towards the operator. This way the motherload of downwards pressure goes onto the USB directly rather than translate into a rotation at the tor-lock.

In this respect the drill jig behaves much like the scissors jig. You can ram it right up to the stone.

The board could by the way be much broader upwards, to provide a wider rest for some big object-to-be-sharpened, if that were needed. Only down at the stone it would need to be confined to the stone in order to sharpen small knifes.

Edit: I just realize that a plain alumnium plate mounted on the drill jig´s base plate this way would probably make for a formidable universal tool rest. An (almost) bargain tool rest if you buy the expensive drill jig...

(I´ll add to this thread. No point in opening a new thread on the very subject.)

I recently got into setting the Tormek with calculated values (T-USB) and I was puzzled how far off the angle master was. I had no explanation for that.

Now at least since Vadim entering the scene, you folks talk about fractions of a degree. I wondered how a blunt device like the angle master with controls that coarse can cater for this.

I now realize that I had used it intuitively (wrong) on the face of a knife with back-taper, fairly to the mid of the knife´s side.

There is not only (as mentioned earlier) an error introduced by the thickness of the blade (increasing with thickness), but also by choosing the wrong reference point:

As a matter of fact, probably only the most inner point of the unit, where the black plastic, the knife´s edge and the stone meet, is of any concern. In other words, measuring on the bevel (such as on a chisel that is straight throughout), which you would think has a consistent angle along its bevel, is wrong by a mile.
(thats what I did).

If something is that critical, it should be adressed by the maker so clear that it is beyond any doubt - which it isn´t.

A chef´s knife may have a single bevel (the edge bevel) approaching a millimeter in size. How can somebody possibly set a meaningful angle using the anglemaster on that?

Needless to say, my recent knifes (since I adopted Vadim´s protocol and setting the angles by calculating T-USB) were sharp at last.

Blessings to you guys who provide those programs freely.

This content fits here nicely.
Just for the record...

If anybody toys with the idea of making such a device but lacks a suitable platform... maybe you have the DBS-22, which has Tor-Lock and all.

This hack is non-invasive (I have however made the recommended mod for the DBS-22).

It uses two big steel washers that have their sides trimmed off slightly to grip into the guide slot. The cylinder screws lock eventually; one may weld them or use glue if desired. Two M6 knurled nuts on the top.

The board is some phenolic resin whose name I don´t know, 10mm thick, similar to the coatings of kitchen boards. Unfortunately the surface is very brittle and does not survive the circular saw.

Mid-ways I realized that what I had planned, does not work, so I did not pursue the idea any longer (for now) and the jig is unfinished.

In the side view you see that the DBS-22´s guide groove is recessed. The add-on board locks perfectly this way, but it is not in parallel to the platform. To have any alleged angle calculations correct, I would next time extend the board towards the upper end, so that it covers the top black plastic slider too.

Tailored for a T-3, it is more aptly called the HK-40

Take a second to behold my moon-shine FVB and the rock-hard felt-wheel.

Hihi, I learned a new word: 'gewgaws'.

I typically remember the useless, but funny words...

I tested the SE-77 settings in your calculator and it worked. 

Thanks for checking this out. I suspected it may work.

@Perra, thanks for this clarification.

I just realize that my quest was condemned to fail right from the start, since the setting of T-USB to achieve a certain angle hinges on a stable projection distance - i.e. a jig that "locks" the knife´s edge to the USB.

How daft. I have created a lot of commotion for nothing.

Perra,

while re-reading your reply the suspicion creeps in that we are not talking about the same thing. Thus the subject is worth revisiting.

While I was initially talking about your T-cube, I was later-on talking about your piece of software that, amongst others, uses the T-cube.

I try to reformulate my question: does your software take into account that some jigs are so thick, that the projection line is shifted several millimeters up resp. out of the center? (In case of the SE-77 this has a fulcrum point at the USB, but the projection line is several cm away).

Dutchman addresses this problem in the aforementioned document; I am not good enough with the math to see it myself, but this may have well been cared for by the jig diameter parameter.

This kind of thing happens if you use the cbwx34-fix or HK-50.

I am quite fond of your "lite" program because it is .... lite for using. And it runs on my system without any Microsoft gew-gaws.

But the idea has not been to use it for anything other than knife jigs.

Thanks. That makes it clear.

I understand that you can use the program in a bare bone fashion. But as I said - it does not run on my PC. So I have to resort to simpler programs.

Actually, I would be quite content with Dutchman´s tables, but as he said himself, they won´t work with the new jigs. Perra´s program´s tables do work for knives, but what I want to be cleared is what I addressed in the thread you mention. That is particularly for using Herman´s jig and chisels.

I am quite positive that it works by changing that parameter.

Perra,
thanks for this great tool.

I am going to have a T-Cube made for me, I think this fits my needs perfectly.

There is one question remaining.
The top of the steel ruler to my understanding takes place of the knife´s center line to a good approximation. Thus the offset of 6mm, provided you use one of the stock knife jigs.

Now to my further understanding, this does not work for jigs whose "center line" (for lacking a better word) is offset by a varying amount, like

• SE-77 (the straight edge jig)
• cbwx34-fix
• Tool Rest SVD-110
• Scissors jig SVX-150
• Homemade Knife Rest HK-50

Dutchman adresses this in his booklet "more math..." in chapter "Changing the reference point for the stone distance". He calls the parameter JC=jig centerline to center of USB offset

It is quite possible that you have taken this into account in your jig diameter parameter, in which case only this one would need to be changed for such a jig. In fact it would seem quite logical, since in your drawing you use the same letters for designating these points.

So calling the parameter jig diameter is a logical step, since all official knife jigs have 12mm and the numbers come out exactly the same for the knife jigs, but if the center line were somewhere else, using this nomenclature were ambiguous.

In fact, even the term jig center line would likely be inadequate for cutting objects that have a single bevel. I cannot imagine myself a term that universally describes the same thing for knives and chisels, but clearly, for a chisel, it will be on the top when grinding. Maybe edge reference line would hit the nail better.

For example the SE-77. Because of its pivot point the center line J is moved far away from C. Moreover, any correct angle has to be set on top of the straight edge (as shown in the Tormek manual). The blade itself may easily be 5mm thick, so that would amount to the offset.

For example the HK-50. Using a plate thick enough (say: 10mm) to clear any knife handle while grinding the bolster, as suggested, will produce a similar discrepancy.

Let me know what you think.

for the record: my T-3 measurements. They are a little different than common T-4 settings, but there seems to be some spread anyway...

• HV=50
• VV=18
• HH=30
• VH=67

however, this fits nicely into the specs:

Current T-4 constants ranges are (including your measurements):

HV 49,0-51,1
VV 19,5-20,0
HH 29,0
VH 66,0-67,0

my FVB parameters are of no concern, being proprietory.

Having that all said (and set), I find that what the program does is waaaayyyy over my head.
Until further demands arise, I will be content with Dutchman´s or Perra´s tables.
As a result, the only additional gadget needed is a working distance measurement like the T-Cube.
This is an insight, and thus an advance.

For the environment needed to run TormekCalc:

Version 2.01 runs on Libreoffice 7.5, but not if you store the file in its native format (.ods).
Current version 3.1 does not run. It gets the links twisted.
But it ran enough tho see that I can survive without. (not trying to be ironic.)

Cudos however for the program and thanks for generously giving it.

I have a T-3 and a self-made FVB, so I have to measure the parameters myself.
I don´t know how much the T-4 resembles the T-3.

May I ask where I can find the description for HV,VV,HH, FVB HF etc.
Preferrably a drawing. There is so much information here... Found the drawing myself.

BTW, I downloaded V2.01 and it works great on Libreoffice 7.5.

Thanks,

-Helmut