Knife Point Setting Template

[Jan]

   That is very interesting, Jan. You are knocking some of the dust off my mathematical archives. You are correct in that definition of point. However, welcome to the English language, the language of EXCEPTIONS. I am not saying you are incorrect, only that our language can be strange at times! Here, (I cannot speak for all English speaking places) we do not normally say the point of the finger but the tip of the finger. Yet, we point with our finger! In pointing, if only the tip of the finger was considered, it would be hard to figure out which direction was being indicated. 

Thank you Elden for an interesting lesson in English. 

Pointing with a fingertip is fine for me, because it indicates direction to a point in space and involves both, the finger and the fingertip.

Here are a few examples of the knife terminology supporting my view, which is in compliance with he following definition:Point - The extreme end of the blade where the line of the back and the line of the edge meet. https://www.theknifeconnection.net/knife-terminology/ .



Adapted from Peterson, Harold L., American Knives, Charles Scribner's Sons, New York, 1958.







After Wikipedia modern knife consists of:
1.   the blade
2.   the handle
3.   the point – the end of the knife used for piercing
4.   the edge – the cutting surface of the knife extending from the point to the heel
5.   the grind – the cross section shape of the blade

6.   the spine – the thickest section of the blade; on a single-edged knife, the side opposite the edge; on a two-edged knife, more toward the middle
7.   the fuller – a groove added to make the blade lighter
8.   the ricasso – the flat section of the blade located at the junction of the blade and the knife's bolster or guard
9.   the guard – the barrier between the blade and the handle which prevents the hand from slipping forward onto the blade and protects the hand from the external forces that are usually applied to the blade during use
10.   the hilt or butt – the end of the handle utilized for blunt force
11.   the lanyard – a strap used to secure the knife to the wrist

Jan

[Jan]

Jan,

Your double ended "kenjig" (Shall we call it the "janjig"?) is very clever. Good job! This topic illustrates the power of a forum. When an idea is shared by interested parties, it improves. It is exciting! Keep up the good work. Incidentally, using the second end for getting the leather honing wheel for the same set up seems logical to me. Having one end for (example) fifteen degrees and the other end for twenty degrees would start to get more complicated and prone to error.

Thank you, Ken! Let's stay with the name double ended kenjig. My contribution was quite small. 

You might be interested to know that I was thinking (musing) about the famous Dutchman tables and came to the conclusion that we do not use them entirely correctly for setting the stone-support distance. Fortunately, the bias is small, only about 1 mm. Let me know if you would like to know more about it.

I can also offer calculation of the stone-support distance for arbitrary wheel radius and projection length. It is not easy to estimate it from the Dutchman tables, because it often requires interpolation. I am testing an Excel spreadsheet for it.

Jan

[Herman Trivilino]

I dunno, but I think if you referred to the point of a knife, or the tip of a knife, most people would think you're talking about the same thing.

Of course, if we want to be more precise we define our terms. The edge of a knife is the line where the two grinding surfaces meet. The end of that line furthest from the handle is the tip.

I agree that the term point is not helpful. There are an infinite number of them in Euclidean 3-dimensional space.

Elden, the website you cited is an excellent source of information. I was disappointed, though, when I clicked on "price" and saw words instead of numbers. I buy my knives with an entirely different philosophy. I think I should pay based on utility alone. I care not at all about looks. I realize those knives are highly useful, but I would venture to guess that most of the knives he makes are not used. They are trophy pieces. But they are exceptionally nice knives nevertheless.

[Ken S]

Good observation, Herman. Trophy pieces are fine for collectors. Like you, I value utility. My kitchen knives, carefully sharpened on the Tormek, do not reside in cases. They work on my wooden cutting board.

Ken

[Tournevis]

I can also offer calculation of the stone-support distance for arbitrary wheel radius and projection length. It is not easy to estimate it from the Dutchman tables, because it often requires interpolation. I am testing an Excel spreadsheet for it.

Jan

Hi Jan, could you please take in account T4 dimensional specification ?
Perhaps a separate Excel spreadsheet ?
Same request for double end Jig, can I take it as it for a T4 ?
Thanks in advance.
Sheang

[Ken S]

Excellent question, Sheang.

If Jan's excel sheet allows for wheel wear, all you will need to do to use it with the T4 (or T3) is use the part for a 200 mm diameter grinding wheel, or whatever diameter wear applies to your wheel.

When I first received my T4 I set it next to my T7. Acknowledging that there are differences, I was surprised by how similar the two models are. The onlt difference in any of the jigs and accessories is that the universal support for the T4 is ten mm shorter. This is for the end safety stop of the SE-76 to work properly with the ten mm narrower grinding wheel. All of the other jigs work the same. In fact, if the T7 grinding wheel is worn to 200mm in diameter, not uncommon, all of the jig settings are identical.

This surprised me at first. I do use separate Anglemasters. One is labelled"T4". This is for my memory rather than anything about the Tormek.

When I made up the kenjig, I used Dutchman's chart from the forum. I noticed that the universal support to grinding wheel distance was about eight mm longer with a 200 mm wheel. My T4 kenjig is cut with an 88mm slot instead of an 80mm slot. (for a fifteen degree bevel).

Because of size constraints, the leather honing wheel must be used handheld with the T4. No double ended jig is necessary for it. This is not a problem. With a little care and practice, hand honing is easily mastered. In fact, I suspect most T7 users use hand honing.

Ken

[Jan]

Ken, Sheang, below you can see two samples produced by my Excel spreadsheet. The spreadsheet, when released,  will enable you to change each parameter shown in black (wheel radius, projection length and bevel angle), and Excel will calculate the wheel-support distances S after Dutchmen and S' after Jan.
S' reflects the way how we measure the wheel-support distance with kenjig.





The first table is for T7 only, the gray columns show the calculation for honing wheel.
The second table is for T3, T4 and also for T7 with a worn stone.

Both tables assume the projection length of 139 mm and show the wheel-support distances for three bevel angles: 15^o, 12.5^o and 10 ^o (i.e. for edge angles 30^o, 25^o and 20^o).



Let me know if it will be useful to you in this form.

Jan

[Tournevis]

Jan
That sounds perfect.

[Ken S]

Excellent work, Jan.

It is regrettable that Dutchman is no longer actively posting. His work is ground breaking. Unfortunately, I think his fine work was too in depth for most of the forum. I found it very useful in developing the kenjig. Useful, but not easy.

Your thoroughness is commendable. I am looking forward to your completed program. I believe we will need two versions to be really effective. Your thorough version and a very simplified stripped down version. I suspect the simpler version will be more used, especially until people begin to realize the full value of the concept.

Keep up the good work.

Ken

[Jan]

Ken, the most simplified version of an Excel spreadsheet entitled "KENJIG_wheel_support_distance_1" is available for download at the following address:

https://www.dropbox.com/s/ypbtaxgycgoyls0/KENJIG_wheel_support_distance_1.xlsb?dl=1

The spreadsheet enables you to change each parameter shown in black (wheel radius, projection length and bevel angle), and Excel will automatically calculate the wheel-support distances, S after Dutchmen and S' after Jan.

The distance S' reflects the way how we measure the wheel-support distance with a kenjig, i.e. between the wheel and the back of the universal support.

The formulas in the spreadsheet are valid for grinding stones and honing wheels of all Tormek machines, including the 2000 and 1200 series equipped with standard universal support made of 12 mm (1/2") round steel and Tormek knife jig or long knife jig. 

Please let me know whether it works on your PC.

Jan

P.S.: My spreadsheet was prepared in Excel for Windows which is the gold standard in spreadsheets. Excel for Mac 2011 is probably the closest to this standard.

[Edwe]

This jig has realy helped me, thanks a LOT

How about to use it with Tormeks jig for long knifes?

[Jan]

You are welcome, Dennis!

I am very pleased that the jig helped you. You can use it also with the Tormek jig for long knives, because the relevant dimensions are the same. The width of the clamps has no effect on the edge angle.

Jan

[Fernando]

Ken, the most simplified version of an Excel spreadsheet entitled "KENJIG_wheel_support_distance_1" is available for download at the following address:

https://www.dropbox.com/s/ypbtaxgycgoyls0/KENJIG_wheel_support_distance_1.xlsb?dl=1

Jan really thank you very much for sharing this valuable material

[Jan]

You are welcome, Fernando! 

I am pleased that it is useful for you. Please keep in mind that the script works for T7 machine only.

Jan

[Fernando]

You are welcome, Fernando! 

I am pleased that it is useful for you. Please keep in mind that the script works for T7 machine only.

Jan

Umm I have is the tormek T-8, and as I have seen there are slight differences in the measurements, but that would affect the final result .