I've been busy trying to see how accurately and repeatably you can grind with a Tormek. I know it's a little geeky and maybe not always necessary with exact angles to sharpen some knives for the wife!
There are several fine and precise calculation programs now that give us all the measurements we need, but I have had difficulty measuring these measurements with insufficiently high accuracy. I think measurements within 0.1 mm are needed! Therefore I use calipers to measure with in my jigs.
Mainly talking about usb height and projection distance. How to easily find the center line on different sizes of wheels and the height of the usb support? How easy and accurate to find projection distance on knives even if you angle them differently in the jig?
I have made two new measuring jigs for this purpose. They help me work faster and more precisely when I work with knife grinding. I can also rehearse my angles and measurements more accurately with these jigs.
Perhaps it may be of interest to some of you to take part of what I have worked with. Or maybe i can inspire someone. Or do you also have ideas on the same theme to share?
More pictures and information can be found in the excel file "Angle Calculator Lite V1.4" which is updated in this link. https://forum.tormek.com/index.php/topic,4885.msg37303.html#msg37303
Perra, both jigs are pretty sharp, cheap pun, but I really like the jig you came up with to measure from the top of the USB to the wheel. Making those slots helps locate it on the radius of the wheel. I wonder how much of the radius of the wheel will protrude into that slot opening though? You might be losing that 0.1mm accuracy your looking for? Have you tried making comparison measurements using the protruding end of a caliper from the top of the USB to the wheel? Again, I do like the concept and really admire the creativity.
Hi
Glad you liked them.
You can compensate for a small measurement errors due to the height of the grinding wheel between the legs. Measurement error for wheel diameter 250 is 0.144mm and for wheel dia 214 it is 0.168mm.
Recommends adjusting the position of the caliper by 0.156mm.
You can read more about it and se more pictures in you follow the link and download Angle Calculator Lite V1.4
Quote from: Perra on November 26, 2022, 02:28:38 PMI've been busy trying to see how accurately and repeatably you can grind with a Tormek. I know it's a little geeky and maybe not always necessary with exact angles to sharpen some knives for the wife!
There are several fine and precise calculation programs now that give us all the measurements we need, but I have had difficulty measuring these measurements with insufficiently high accuracy. I think measurements within 0.1 mm are needed! Therefore I use calipers to measure with in my jigs.
Mainly talking about usb height and projection distance. How to easily find the center line on different sizes of wheels and the height of the usb support? How easy and accurate to find projection distance on knives even if you angle them differently in the jig?
I have made two new measuring jigs for this purpose. They help me work faster and more precisely when I work with knife grinding. I can also rehearse my angles and measurements more accurately with these jigs.
Perhaps it may be of interest to some of you to take part of what I have worked with. Or maybe i can inspire someone. Or do you also have ideas on the same theme to share?
More pictures and information can be found in the excel file "Angle Calculator Lite V1.4" which is updated in this link. https://forum.tormek.com/index.php/topic,4885.msg37303.html#msg37303
I really think that "measurements within 0.1mm are needed"... should come with a bit more of an explanation, since, for the most part, it's really not needed.
So.... why? :)
Nice job on the jigs though... A+ for accuracy and consistency. I just think that trying to compensate for fractions of a mm, (can you have fractions of a mm?) ;D isn't really necessary.
Quote from: Perra on November 30, 2022, 10:35:33 AMHi
Glad you liked them.
You can compensate for a small measurement errors due to the height of the grinding wheel between the legs. Measurement error for wheel diameter 250 is 0.144mm and for wheel dia 214 it is 0.168mm.
Recommends adjusting the position of the caliper by 0.156mm.
You can read more about it and se more pictures in you follow the link and download Angle Calculator Lite V1.4
Again (although this is a little different than trying to achieve the .1mm accuracy)... wouldn't you get the same result if you didn't adjust for this error? If you're always adjusting the caliper by "0.156mm" (since it reads that you are, regardless of wheel size), would it be any different than if you didn't? (Hope that makes sense.)
Quote from: cbwx34 on November 30, 2022, 04:53:53 PMAgain (although this is a little different than trying to achieve the .1mm accuracy)... wouldn't you get the same result if you didn't adjust for this error? If you're always adjusting the caliper by "0.156mm" (since it reads that you are, regardless of wheel size), would it be any different than if you didn't? (Hope that makes sense.)
It makes a significant difference : You will be 0.024mm closer to the honing wheel. So probably honing at a 0.018° lower angle than you're trying to !!! Instead of just 0.009°. But then you'd be sharpening at a 0.009° higher angle. So more precise, but not more accurate. Or the other way around ?
I can agree with you cbwx34 that it may not always be necessary in practice with such accuracy, within 0.1mm. But that's not my point here.
I think it's up to everyone to decide how exactly they want to try to get their angles. But the more you know, the more precisely you can grind. Learning how what you do and how it works, both in theory and in practice, is education. And my ambition is to learn as much as possible to understand what I am doing. Therefore, I am thinking, measuring and producing jigs that can match the factually correct values of the calculation programs. And try to get as close as I can. In that case I think "measurements within 0.1 mm are needed!" I hope I managed to answer your question
I believe that the more I understand the more I become a better sharpener And it has also given me tools so I can measure and tune my Tormek both faster and better when am working. I also share it with you all and it is up to each of you to decide if or how you want to use them or not and how accurate you wont to measuring. Don't get me wrong, I'd love for you to come up with suggestions for improvements or correct me if I'm on the wrong track. With an adjustment of 0.156mm on the caliper you are less than 0.024 error from all wheel sizes within 250 to 214 but again it is up to each individual to set the tolerances.
I think we are entering the accurate vs consistent debate again here. I'll tell you a bit about my journey. I obsessed with accuracy for a long time, trying to replicate Wootz protocols with similar Bess scores. Then with research I went for consistency across all formats so to speak- setting edges on Tormek wheels, honing on Tormek leather wheels, refining on paper wheels etc.it is easy to disappear down rabbit holes with both and tie yourself in knots.
CB helped me to realise that a compromise between the two works.
3D Anvil taught me to experiment and find my own way.
Depending on what you are hoping to achieve find a way to get the results you are looking for. It will take time and learning but you will get there.
Anything under 100 Bess is good enough for me and my customers.
The sub 50 Bess we all want to get for all knives under any conditions is a rabbit hole not worth exploring in the real world I have concluded.
Having said all that, personal correspondence with Wootz just before he died, recommended getting ALL measurements within 0.1mm. Those were the tolerances he was recommending.
So...... the debate will continue.
You can't argue with Wootz's results, but I think 0.1mm tolerances are simply not attainable with the tools in question. Even if you measure to that accuracy, the USB moves slightly when it's screwed down. Then, even if you stay with wheels the whole way, you're going to be using wheels of different diameter (paper wheels and/or leather wheel), so you're not hitting precisely the same spot on the bevel from one stage to the next. And of course the Tormek jig isn't locked down, so there's always some variation as you move the knife across the wheel.
I haven't been using the Tormek system nearly as long as many others here, but my feeling is that, while it helps to be reasonably precise, attaining sub-50 BESS scores requires technique and lots of practice.
I think we are talking about two different things here. Knowing which angle you grind with and being able to repeat it in the future is one thing. Getting the ability and skill to reach below 100 bess is another matter. You can probably reach about 80 bess with 14, 15, or 16 degrees or without knowing which degrees you grind with. It also depends on which stone you use, how you hone, if you polish with a paper wheel or rock hard felt wheel, diamond spray etc. I find that my customers are most satisfied if the knife works as they expect and I believe that the right angle for the right knife and field of use is more important than 80 bess. (which most people don't even know what it is)
A working knife must also last as long as possible and then perhaps a higher angle is better for that particular knife. With perhaps a higher Bess number! But I want to be able to repeat that result and that angle again.
What do you think?
Or am I thinking wrong?
No I don't think you are "thinking wrong" at all.
There are three things of issue here:
Accuracy ( your desire or Vadim's desire for accuracy down to 0.1mm)
Consistency.
Repeatability.
I would argue that the second two of these are interdependent.
The first is also very important for the 2nd and 3rd to be achievable.
But I think if you put all the emphasis on accuracy then you may be putting less emphasis on the consistency and repeatability.
In real world sharpness, as you say, 80-100 Bess is more than adequate for a customer who can't tell the difference. If you can achieve these results ( I always try to for my sense of pride and job satisfaction) then that's great. If you can consistently repeat the process without looking at software and calculators and trying to raise the Usb by 0.1 of a mm, then that's even better.
Sharpening for customers becomes uneconomical if your main objective is accuracy, the repeatability and consistency are more important as speed of process becomes an important factor.
I am not advocating prioritising speed over accuracy. If you wanted to do that then get a belt grinder and learn how to sharpen super fast and not necessarily super accurate or even super repeatable or consistent.
Tormek use is never any good done at fast pace. It is a great tool to use PRECISELY because it can be used consistently and repeatably to a good level of accuracy.
I feel like I have one foot on each side of this debate. I want to state up front that I do not intend to be critical of either side. Nor do I feel that the two sides are mutually exclusive.
I have a hobby interest in precision machine shop measurement which predates my starting with my T7 by many years. My interest in automating accurate jig setting with my Tormek actually predated the kenjig. It began with chisels and was designed to eliminate the need for measuring each tool. The kenjig uses the concept of gage blocks. The highest quality gage blocks are capable of accurate measurement within a very few millionths of an inch. Naturally baltic birch plywood kenjigs are nowhere near that accurate, although I am certain that they can give digital calipers a good run for the money. I understand the desire for maximum precision.
On the other hand, I also appreciate the desire for practical sharpness as expressed by Stig in his online class. I feel that knives sharp enough for the Swedish Culinary Team meet or are beyond my needs. I was an early convert to BESS, although my goal is sharpness adequate for my needs instead of meeting a number. I make no claim to being very scientific, nor do I criticize those who are.
We have different sharpness expectations. I support this diversity. A "farmers market" sharpener sharpening many knives at $5 each fulfills a valuable service. So does the sharpener who strives for optimal excellence typical of Wootz. We must not forget the home sharpener who sharpens knives for himself and his spouse. I want our forum to serve all of our needs.
Ken
I agree with you Ken. Different ways to reach a sufficiently good result must be good. I think Sir A has several good and wise points as well. And sometimes I think it's good to fall down a rabbit hole to learn. Sometimes I joke and call it a mess tester when people want to compete in "Bess" it looks like a deep rabbit hole at the end. Sorry for the bad English but it's a joke!
Cbwx has a good point of view with "wouldn't you get the same result if you didn't adjust for this error?" If you always measure with a small error, the result will always also have the same small error. This can become perfectly acceptable if you continue to "measure wrong" over time and accept the small error.
I think Ken agrees with this. -If you want useful results from measurements, you have to measure with the same technique every time, it is the difference between the measurement results that is most important. do not change the measurement method, you will soon not know what the results mean.
I very much appreciate your answers and that you challenge and develop issues with your experiences. Thanks
My problem is probably that I like rabbit holes! Maybe I'm a little crazy. Or much!
As an old retired engineer with long experience from manufacturing tools, jigs and prototypes, I have a built-in interest in solving problems and taking on every challenge. Sharpening knives, drills and similar tools is now my hobby but I enjoy just as much solving any problem I come across and trying to make a tool or jig for it.
And now I may have fallen down a new rabbit hole. An old friend of mine, very good knife sharpener, came to me and asked if I could build him a simple jig to set his knife angles but without having to use calculators or measure wheel sizes, usb height or other measurements. He doesn't use computers or smartphones that much and is quite analog. But he has discovered a need to be able to know what angle he is grinding with and to be able to set a specific angle. And he is not comfortable with Tormek's anglemaster on knives.
Has anyone of you worked with the same "rabbit hole" sorry! and maybe have ideas about solutions.
I have come a little way and am in the process of testing a prototype that can handle an accuracy of approx. 0.5 degrees right now.
Good post, Perra.
Similar to your helping your friend, my interest in automating jig set up with the Tormek began in 2009 by wanting to help a forum friend. He was a good fellow up in years with a keen mind and visual limitations. Fortunately, the Tormek is quite adaptable with innovative users.
I look forward to your innovations.
Ken
Quote from: Perra on December 19, 2022, 01:19:46 PM... snip
... a prototype that can handle an accuracy of approx. 0.5 degrees right now.
I'm curious, show it. An accuracy of 0.5 is certainly good enough.
The black marker method can be used for re-sharpening.
In industry, tolerance ranges are well established. Different grades of threads have well defined tolerance ranges. (See the link for a description of this:
https://www.boltscience.com/pages/screw8.htm) Fits have different tolerance ranges depending on whether the two parts must slide of remain in place.
Bevel edges on knives or woodworking tools do not have to mate with another part. We want our edges to be sharp. We want our bevel angles to be in an appropriate range for the intended tasks, and we want double bevels to be visually "matching" to the naked eye.
Ken
PS. I believe in the old maxim that a rising tide raises all boats. Regardless of our individual sharpening expectations, we are all indebted to the intrepid forum precision pioneers who continue to push back the frontiers of sharpening.
I would agree that it is desirable to meet the intended angle with not more than 0.5 deg deviation.
I have played a bit with the calcapp Knife Sharpening Angle Calculator to find out which deviations in Projection Distance or Distance to the grinding wheel would cause an 0.5 deg error.
For a single measurements, up to 0.7 mm deviation is allowed.
In case that both measurements are affected by an error, it is sufficient to measure both data with an error of not exeeding 0,4 deg.
An measurement error not exeeding 0.1 mm would only be needed if it is planned to meet the desired angle with an error of less than 0,1 deg.
While I agree that +/- 0.5 deg error can be achieved with the Tormek system, I strongly believe that an angle error of less than +/- 0.1 degree cannot be repeated on a Tormek system. Even when Projection Distance and distance to the grinding wheel would be measured without any error, the sum of all other errors and tolerances would cause that the resulting angle cannot be maintained repeatedly.
I therefore, do not see any benefit in measuring Projection Distance or Distance to the wheel with extreme high precision.
I have collected some pictures and user information about my latest project, WAT-prototype, in a pdf file. Attached below. Happy to receive thoughts and ideas about how a finished jig could look like! Or thoughts about function and precision. Have tested it on different wheels and with varying degree numbers and jig lengths and so far I am positively surprised by the result. The T-cube has already been presented before.
With this two tools you can set the grinding angle for knives on a grinding machine with rotating grinding wheels or honing wheels from Dia 200mm and up without using a calculator. There is no need to measure wheel size, usb height or projection length. It is possible to set degrees with an accuracy of 0.5 degrees.
There is already a small thought with me to produce a template for a 3d printer if it works well and if someone wants it. However, it is quite easy to make it yourself if you want.
A clever idea and beautifully executed!
However, the tolerance is greater than the stated 0.5°.
The variation in stone diameter (150-250 mm) already gives a tolerance of 1.27°. See attachments.
Other adjustment tolerances are added to that.
Review of wheel angle tool.pdf
Hi Dutchman
I have the same result as you have. So that's good.
But I have calculated wheels from dia 200 to 250 and that gave me 2mm variation, then I moved up the center point of the scale 1mm to halve that error. Maybe it's not quite right to do that? but as you point out, there are more parameters to consider. It is also a bit difficult to hit the right spot with the ruler. Do you have any other solution to reduce the margins of error on?
The Jig/Tool that Jan, RickKrung, and others worked on came to mind, might want to take a look?
https://forum.tormek.com/index.php/topic,2639.msg24567.html#msg24567
(It's a long thread, but I linked to where it seemed to pick up again when Rick worked on it.)
Edit: Here it's described in Rich's site: https://www.sharpeninghandbook.info/indexJigs.html#HanJig
Gotta say though, this is one instance where I'm thinking the KenJig might be the easiest route. It's pretty tolerant of wheel size changes, (you don't have to measure that often, and can just use the scale on the machine), and is easy to use.
At some point, you gotta measure something... if your friend doesn't want to use a "calculator"... then maybe a spreadsheet would be just as easy. (You're technically measuring the Projection in your setup, are you not?) ???
Quote from: cbwx34 on December 20, 2022, 03:20:25 PM...snip
... then maybe a spreadsheet would be just as easy.
... snip
And what is wrong with my tables?
Quote from: Dutchman on December 20, 2022, 04:00:02 PMQuote from: cbwx34 on December 20, 2022, 03:20:25 PM...snip
... then maybe a spreadsheet would be just as easy.
... snip
And what is wrong with my tables?
Nothing... isn't that the same thing? ???
Thanks a lot CBW I will definitely read through your suggested threads.
Yes, maybe Kenjig is a good solution for him too. Yes, I admit, I cheated a little. Technically, I measure projection distance but without noting any values. I just physically copy the length to the T-cube. Think it is technically impossible to try to solve this without having at least one fixed value to start from.
My goal is to avoid both calculators and measuring tools such as calipers etc.
And he knows the marker pen method. I told him the black one is 18 degrees and the blue one is 16... but he didn't believe me!
He has tried it a bit and is not satisfied with the handling. There are too many loose parts to handle at the same time as he has to read the scale and raise the usb support.
I am now looking at version 1.1, where the parts should fit together and make it easier to handle with one hand.
That's why I'm waiting with tables of measurements that still have to be measured somehow.
Hope that it is possible to find an acceptable level of the deviation in some way. The tests I do show that I hit very close to 0.5 degrees when I countermeasure with other methods.
Don't know what deviation Tormek's Anglemaster has.
What deviation do you think is acceptable on a tool like this to use it?
Quote from: cbwx34 on December 20, 2022, 04:36:39 PMQuote from: Dutchman on December 20, 2022, 04:00:02 PMAnd what is wrong with my tables?
Nothing... isn't that the same thing? ???
only if it is on paper instead of electronically ;)
Quote from: Dutchman on December 21, 2022, 11:02:02 AMQuote from: cbwx34 on December 20, 2022, 04:36:39 PMQuote from: Dutchman on December 20, 2022, 04:00:02 PMAnd what is wrong with my tables?
Nothing... isn't that the same thing? ???
only if it is on paper instead of electronically ;)
That's actually not correct. (https://blog.coupler.io/spreadsheet-vs-database/#:~:text=Spreadsheets%20are%20tables%20consisting%20of,(structures)%20for%20storing%20data.) ;)
Quote from: Perra on December 20, 2022, 06:37:59 PM...
My goal is to avoid both calculators and measuring tools such as calipers etc.
...
I think part of the issue (maybe) is we took Dutchman's idea... "A
Simple Adjustment of the Grinding Angle" and made it appear more complicated. For me, a calculator is easier to use, I'm not constrained to a set Projection, Angle, etc. But using a
table and a simple ruler (I like a combo square), you can easily set the angle consistently and probably more than accurate enough. Saying computers/calipers/etc. just makes it seem complicated (and I think a bit overkill for most). My .02.
For the record, my main goal in designing the kenjig was to avoid having to measure for every knife. My goal was NOT to avoid "calculators and measuring tools (including computers)". The purpose of the kenjig is to be able to preset both the Distance and Projection. Dutchman's tables allowed me to do this easily. More recently, CB's Calcapp works well, also. In rare cases, such as sharpening my Chinese cleaver, I need to make up a new kenjig. A simple cardboard kenjig suffices for situations like these.
Ken
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. :)
Very interesting. Will you be placing the final 3D files for download somewhere?
"Don't know what deviation Tormek's Anglemaster has.
What deviation do you think is acceptable on a tool like this to use it?"
It is important to remember the function of any measuring tool and its practical deviation. Even a world class precision toolmaker like Starrett makes tools of different deviations for different requirements. Even Starrett's basic protractor type tools for measuring angles are reasonably accurate. The hash marks on its measuring tools are "engine cut" with sharp v shapes, rather than photo etched. Its more accurate protractors have more precise verniers and measure to five minutes or arc. (60 minutes of arc equal one degree) This level of accuracy is adequate for most tool and die work. An anglemaster of this accuracy might cost several hundred dollars.
For laboratory work, precision angle gage blocks are necessary. At this level, these gages are generally shipped to the National Bureau of Standards periodically for inspection and be priced accordingly.
The Anglemaster, like all measuring tools, is a balance between adequate precision and reasonable cost.
I have happily used Dutchman's tables since he first posted them in 2013. They are still my "go to" reference, although I sometimes use and like CB's Calcapp.
The real advances in knife sharpening are coming in honing, deburring. I don't see any real benefit in ultra precise bevel angle setting. I see real benefits in more thorough deburring.
Ken
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
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.
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
Quote from: Perra on December 20, 2022, 06:37:59 PMDon't know what deviation Tormek's Anglemaster has.
Quote from: Ken S on January 25, 2023, 04:25:29 AMAn 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.
Quote from: Perra on January 25, 2023, 01:15:32 PMI 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
Quote from: Perra on January 24, 2023, 12:36:41 PMA 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).
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.
Perra
Quote from: Perra on January 24, 2023, 12:36:41 PMthe 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?
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.
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.
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
Quote from: HaioPaio on January 29, 2023, 10:40:49 PM...
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.
...
Quote from: Perra on January 30, 2023, 11:11:42 AM...
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. :D 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.)
Quote from: Perra on January 29, 2023, 09:03:23 PM...
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.
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I've also compared angles with other sharpening devices, and am satisfied with the results.
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.
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?
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.
The final version of this tool now looks like this. I've made a number of it that I've sent off to knife sharpeners who want to help test and evaluate it. Maybe it will be available for purchase in the future, if it gets good reviews. The scale forumWAT.jpg Its not gold, only brass!
Quote from: Perra on March 15, 2023, 11:02:13 PMThe final version of this tool now looks like this. I've made a number of it that I've sent off to knife sharpeners who want to help test and evaluate it. Maybe it will be available for purchase in the future, if it gets good reviews. The scale
forumWAT (1).jpg
Its not gold, only brass!
Lookin' good! :)
Interesting tool, Perra. I look forward to learning more about it.
Ken
Neat!
Wow Perra that looks Great!
I look forward to placing in order.
Martin,
If you place an order, please do so off the forum by contacting the seller by PM.
Ken, Forum Moderator