A small useful 3D printed tool

[Perra]

I myself sometimes have a need to print out simple tables for angles and distances etc. to be able to work a little faster and without a computer.
So I have created my own excel sheet for this purpose. Inspired by Ton Nillesen.
For those who like paper tables to have by the side when you grind like me I have added a function to my Angle calculator that gives the possibility to customize and print a table for distance between Top of Usb and grinding wheel adapted to different angles and jig lengths.
You can found it under the worksheet USB-->Wheel in "Angle Calculator Lite V1,3"
Hope someone like it.
Angle Calculator Lite V1,3 is attached below

[Dutchman]

...
For those who like paper tables to have by the side when you grind ...
...

With the new Self-centering Knife Jig KJ-45, the projection distance can no longer be adjusted, due to the removal of the adjustable stop. My tables, however, were based on coarse adjustment with the usb and fine adjustment with the adjustable stop. These are therefore no longer usable with the KJ-45.

So thank you very much Perra for this spreadsheet. If I buy the KJ-45, I will gratefully use your workpiece. Also compliments for the beautiful design.

I imported the spreadsheet with the open source office package LibreOffice. It worked without problems and I saved it as .ODS file.

[Perra]

Thank you very much Dutchman for your review. It was much appreciated

[Ken S]

Perra,

I like your table. You have certainly based it on an excellent source. Ton Nillesen's (Dutchman) tables have served as the inspiration for all of the forum based setting programs and mechanical setting devices. My own kenjig relies heavily on Ton's grinding angle tables for its accuracy and repeatability.

Based on my rather simple needs, I would suggest using your table as an intermediate step, a reference. (Others may have more demanding requirements.)

When I designed the kenjig, I made two jigs, one for 15° per side and one for 20°. Sharpening kitchen knives, I have only used the 15° jig. Except for a master reference table, I would suggest a stripped down final table with perhaps four angles (10°, 12°, 15° and 20° for example). I would be tempted to make up individual one angle cards.

With the Projection, using the SVM jig, I have standardized mostly on 139mm with paring knives at 125mm. I would start projection at 125mm and consider a high limit of 145mm. I would keep your present high Projections on the reference table for use when sharpening cleavers.

With either the SVM or new KJ jigs, there is a range of Projection in the jig clamps. While the KJ is not adjustable, the knife can be inserted up to 15mm. Subtracting the minimum 2 mm holding distance, that still allows 13mm of adjustment in the clamp. For a "margin of safety". let's figure 10mm. If our stripped down chart lists Projection in 4mm increments, we are still covered. I do not believe the reduced adjustability of the KJ jigs will prove to be as major a constraint as some believe.

Kudos for your table. It is a useful idea.

Ken

[Sir Amwell]

Hi Perra. I'm going to get a 3D print of your jig. Thanks for sharing!
Was wondering about the hole for the ' locking nut'. Will the 3D print print the hole? If it does will it be threaded? If so what is the thread for it? Obviously if not then it should be easy to drill and thread one's own?

[Perra]

Hello Sir Amwell
Yes, The hole is printed in the 3d model, dia 6.8 mm, and I have then threaded by hand with M8 *1.25 mm tap. But you can choose the thread that suits you if you can change the file a little or choose a larger thread diameter and drill the hole a little bigger.

[Perra]

The "Angle Calculator Lite V1.4" is now updated with two more measurement jigs and some small adjustments.
The file is attached down below.

[aquataur]

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.

[Perra]

Hi
Sorry; I'm probably not quite sure I understand your question. But the idea has not been to use it for anything other than knife jigs.

[aquataur]

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

Thanks. That makes it clear.

[Ken S]

Perra,

I think you have designed an innovative, useful tool. The question comes up with every tool design, Do we design for general purpose or to excel for one task?

I would rather have a tool designed to excel at one task. If I neededa similar tool for any of the other mentioned jigs, I would prefer to have a second tool specifically designed for that task.

Ken

[aquataur]

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.

[Dutchman]

... snip
And it runs on my system without any Microsoft gew-gaws.

Hihi, I learned a new word: 'gewgaws'. I googled the meaning: "... They're not valuable or useful." Typical for many controls in Microsoft's products.

[Perra]

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).

Hello
The program is also designed to be used only for knife jigs. In settings you can adjust the jig diameter for different jig thicknesses, for example my KJ-45 is 11.8mm in diameter. There is no possibility to move the fulcrum to fit other types of jigs.
This might be a 'gewgaws'

[cbwx34]

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).

Hello
The program is also designed to be used only for knife jigs. In settings you can adjust the jig diameter for different jig thicknesses, for example my KJ-45 is 11.8mm in diameter. There is no possibility to move the fulcrum to fit other types of jigs.
This might be a 'gewgaws'

I'm pretty sure you can.  I learned it from jvh in this thread that the formula is a bit "generic" (for lack of a better word?). It will calculate the USB height, as long as you can figure out the Jig Diameter, and Projection Distance adjustments.

jvh has provided some of this information under the "Jigs" tab of TormekCalc.  I tested the SE-77 settings in your calculator and it worked. 

So, as long as a person can figure out the Jig Diameter and any Projection Distance adjustments,  the calculator should work.