Measurement Jigs for Usb hight and Projection distance settings

[Dutchman]

As I said before: "a clever idea".
I cannot recognize in the photo how the stone diameter is set. but with that adjustment your design will be very suitable and above all easy to use.
I suppose there will be a lot of potential customers

[Perra]

Hi Dutchman You can slide the scale up or down to set the wheel size between 200 to 250mm. It is approx. 1 degree between 200 and 250

I understand and agree with your views Ken. However, this tool is not intended to be a precision tool, it is intended to simplify and speed up the setting and to avoid measuring and keeping track of various measurements and calculations.

[Ken S]

Perra,

I believe we are essentially on the same page. I admit that I probably overfocused on your precision thoughts and need to look more closely at your measuring tool. I will study your ideas more thoroughly and post my thoughts.

Ken

[tgbto]

Don't know what deviation Tormek's Anglemaster has.

An anglemaster of this accuracy might cost several hundred dollars.

[snip]
The Anglemaster, like all measuring tools, is a balance between adequate precision and reasonable cost.

For the sake of those reading this thread before many others on the AngleMaster, I think we might as well be precise :

In addition to the deviation due to user error or manufacturing tolerances, the Anglemaster has a systemic error of exactly half the angle between the sides of the blade (in dps). So the question is not only one of deviation, but also the fact that the AngleMaster is suitable for chisels but not knives. A 1.5dps systemic error when the manual gives 15dps for some uses and 20 for others is a lot.

[Ken S]

I understand and agree with your views Ken. However, this tool is not intended to be a precision tool, it is intended to simplify and speed up the setting and to avoid measuring and keeping track of various measurements and calculations.

Perra, I had a chance to study your tool. I am impressed. You and I are definitely on the same page striving for simplicity. Just as the Tormek is capable of a wide range of sharpening requirements, you and I have different ideas of "simplicity".

When I first started designing the kenjig, I had three target audiences in mind. The first group was new users. The kenjig was designed to simplify the learning curve by allowing the newby to concentrate on grinding without worrying about setting the machine and knife jig. The second group was very infrequent users, the home basement sharpener who sharpened his wife's kitchen knives once every year or two. Again, the kenjig allowed the infrequent user to focus on grinding. The third group came later. This group included farmers market sharpeners who regularly sharpen a hundred knives on a Saturday morning. The automated setting with the kenjig shaved time off of every knife.

At the time, all of my kitchen knives were Henckels. I decided to standardize on 15 degrees per side bevels. With a 15° kenjig and my marker, I can handle the majority of my knife needs. Fine tuning can be augmented with the microadjust, if needed. I understand that other users may want more versatility with angle adjustment.

Other forum members suggested variations on the basic kenjig to automatically compensate for wheel wear. I wasn't too worried about this. Lengthening the groove for Distance setting by one millimeter for each ten millimeters of diameter wear will compensate for this. Occasional sharpeners can go a long time before needing to make adjustments. Also, diamond wheels do not change diameter.

Please continue with your innovative ideas. That is how our forum grows.

Ken

[cbwx34]

A little update on what became of this project. Now the tool is ready and printed on my 3d printer. We are happy with the result and my friend uses it in his workshop.
The scale is now adjustable for different wheel diameters, 200 - 250 and also the length of the ruler's protrusion if you want to be even more precise. You can easily set the length of the jig with a knife directly on the tool. All the parts fit together and you can lock the setting with locking screws on the back, if you want, after making a setting. We find it easy and fast to work with and the accuracy meets the requirements we had, within approx. 0.5 degrees. End of this project.

Nice job.

Does "...also the length of the ruler's protrusion if you want to be even more precise" mean keeping the end of the ruler lined up with the little point sticking down?

Seems like a nice alternative to using a calculator... hope it catches on, (if that is your interest).

[Perra]

Thanks CBWX.
It is correct, as you noted about to be extra precise, you can slide the ruler in or out to hit the "zero point". There is a difference of 0.58mm on the ruler's protrusion to hit the zero point between a wheel of 200mm and one of 250mm. But it is of course difficult to adjust a ruler 0.58mm without the help of a measuring tool. As I mentioned earlier, it is not meant to be a precision tool, so I have chosen to set the ruler to a fixed measurement in the middle 0.58/2=0.29mm. That is sufficient to reduce the margin of error to an acceptable value. There is a built-in option, settings ability between 23.7 and 24.3, to adjust this in the tool. Measured from the tip of the ruler to a specific point. I have set, and use, 24mm for all wheel sizes. The same thing with the wheel dimension on the scale, there is a very small adjustment between 200 - 250 wheels (only 1 degree) so to adjust for example a 240mm wheel, you hardly move the scale at all. After a while you learn when you need to move the scale to be within the tolerance you want. As few settings as possible is a goal.

[HaioPaio]

Perra

the accuracy meets the requirements we had, within approx. 0.5 degrees.

How did you measure the bevel angle of a knive after sharpening to verify that accuracy?
 

[Perra]

Hi HaioPaio
That's a really good question. I think many people, (grinder) out there, like me, have a hard time verifying the amazing results we achieve with our Tormeks. Especially when we have to measure and prove the grinding angles we say we grind at.
When it comes to verifying the ability of the tool WAT, I have worked with control measuring with a number of other methods. USB heights and projection length from calculation programs that I then compared to what WAT shows etc.
But back to your question.  How to measure a knife's bevel angle!
I have tried several different ways, one is to use a laser protractor or laser Goniometer for knives. But my experience is that it is difficult to measure closer than approx. 1 degree or more with a laser pro. See picture
Another way I have tried is with a microscope where you can measure angles, lengths, etc. but it is both a bit complicated and requires some knowledge and special equipment. The way I use right now is to use another sharpening equipment that I have made to sharpen really fine knives with. It can also be used to check existing angles with.
I would like to show some pictures of how it works, but unfortunately I am traveling this week so if I can get back to you in approx. a week I can post more information about this.
 In the meantime, there may be others in this Forum who want to share how they do it.

[HaioPaio]

Perra
I'm using a laser goniometer as well and agree to your assumption.
There is no guarantee to achieve an accuracy better than 1 deg.
It may very well be the case that you could adjust your Jig to 0,5deg. However, I strongly disagree that you could sharpen a knife with your Jig to that accuracy.
The good thing is that is not important.
Your Jig is a great solution for sharpeners who do not want to use the other available solutions. It seems to be simple and straight forward in using it. My only disagreement is the continued misconception regarding the achievable result in bevel angles and the repeatability of that angle on the same knife at another point in time.

If you can demonstrate that, if you had sharpened a knife to a certain angle, used it until dull, and then sharpened it again with your jig.
Marking the bevel with a black marker bevor sharpening would reveal if you could hit that angle exactly.

I would give a big WOUGGHH for that result.

For the time being, I like your work and the person gifted with it can be proud.

[Perra]

Thanks HaioPaio
To be honest, the only thing the tool really does is help you adjust the USB height to a defined value taking into account wheel size and jig projection distance. You then sharpen your knife with a grinder and selected jig and use the setting you have made. The tool is not used for the grinding part. So you have several points with your comments. The accuracy of the tool can of course be compared to other methods of setting the USB height, but it does not guarantee how you grind and whether you reach the angle you think you have set. There are many parameters that come into play as we all know. Kind of grinding wheel, material in the knife blade, how to handle the actual grinding and honing with pressure, speed etc. I think the tool can repeat the setting as well as many other methods at least theoretically but as you said it doesn't really matter that much it's more of value that it is a simple and fast operation that you believe works for you. If you then grind 16.5 or 17.5 degrees is not so important only you are satisfied and proud of what you have done. The main goal of this project was to simplify the setup process and not have to measure so much and not have to use a calculator, and I have come pretty close to that, I think. Accuracy was not that important. 0.5 was a measurement value on the road that I actually chose because the scale is divided into half degrees.
I think the interesting question of being able to repeat a grind at the same angle multiple times is a different issue regardless of what tools you use to set up your machine. Maybe requires its own thread?

And with that said, I have to admit one thing. To sharpen precise angles on knives, I use another grinding tool that is more precise than the Tormek can handle. Sorry Tormek

[cbwx34]

...
If you can demonstrate that, if you had sharpened a knife to a certain angle, used it until dull, and then sharpened it again with your jig.
Marking the bevel with a black marker bevor sharpening would reveal if you could hit that angle exactly.

I would give a big WOUGGHH for that result.
...

...
I think the interesting question of being able to repeat a grind at the same angle multiple times is a different issue regardless of what tools you use to set up your machine. Maybe requires its own thread?
...

Maybe it does require a new thread, 'cause I don't find this to be an issue.  I think most settings are probably within a degree.  (BTW, with a bit of testing, you'll find that within 1° you'll usually remove all of the marker in a pass.)  The consistency of the setup using a calculator is usually very consistent.     I don't see why it wouldn't be the same with this setup.  (And I don't think it needs to be more accurate, even though it may be.)

...
The way I use right now is to use another sharpening equipment that I have made to sharpen really fine knives with. It can also be used to check existing angles with.
...

I've also compared angles with other sharpening devices, and am satisfied with the results.

[3D Anvil]

I can tell you that, using cbwx34's calculator, I am able to repeatably sharpen knives to within around .25° of the intended angle, confirmed by goniometer.  Maybe closer than that, but my goniometer isn't that accurate. 

[Sir Amwell]

Maybe another way to gauge the consistency of angles using such a jig across formats ( eg from grinding wheel to leather honing wheel to felt wheel to paper wheels) where a protocol is being followed (eg one of Wootzs for a particular knife steel) would be the sharpness results. Sure you can test on a goniometer to within 0.25 of a degree but what will matter is the final sharpness results? If the jig doesn't allow for consistent and repeatable angles across formats then final sharpness will surely be compromised.
For me the proof of the pudding would be sharpness rather than what my goniometer is telling me.
Or am I missing something?

[tgbto]

You could have a sharp convex edge, where you'd have consistently ground a non-constant angle and still be very sharp, making up with technique what the jig lacks in precision.

I think there's a bit of a logical flaw in saying that as Woot'z creed to get sharp knives was angle consistency, then if it's sharp it must be consistent.

Also you could have ground a very precise angle and still left a bit of a burr so lower sharpness than someone whose angle would vary more but with better deburring.

To put it another way, it seems to me the equivalent of saying "To drive precisely you need properly inflated tires so if you compare two drivers on a racetrack changing tire pressure in between the two runs, the fastest one has the tire pressure closest to the optimum"

If you want to judge angle stability, the dispersion of a reflected laser will give some information. If you want to judge angle accuracy within .25°... Well good luck setting up the proper test environment in the first place.