Which FVB design to use to link it to good software

[WimSpi]

Wim,

Bravo! You are on the right track. I have never understood the reasoning for using the frame as the measuring reference point instead of measuring directly from the wheel. Guided by Dutchman's grinding angles booklet, I have used Dutchman's direct to the wheel method for eight years with my kenjig. No compensation is needed when switching from the T7 to the T8. Using Dutchman's tables with diameter changes, the direct measuring with kenjig works with no modification with the T4.

Borrowing Wim's depth gage idea, the kenjig could be modified to eliminate the need to purchase a depth gage. Shorten the slot to around one inch. Mark the kenjig with the Distance. You will need to make up several kenjigs with different Distances.

With the KJ-45, there is easily a range of 10mm. Using CB's Calcapp, enter Projection values from your widest to your narrowest knives. Note these values and use them to make up kenjigs. These kenjigs will be gage blocks, having the same measurement year in and year out with no need of resetting. The Projection could be adjusted match one of the kenjig Distances.

Kenjig instructions are posted on Rich Colvin's Sharpening Handbook.

Ken

Ken,

Thank you.
By measuring on the FVB, you have to measure very accurately, to tenths of millimetres and the exact 90 degrees of a carpenter's square. Otherwise the setting will be imprecise.

But the risk is that you can get lost in an idea of accuracy that is not realistic for the grinding process.
The tools' calculations encourage this line of thinking, as they (understandably) calculate to 2 decimal places.

To be clear, I have a lot of sympathy for the developers of the calculation models. Please continue to do so.

Wim

[cbwx34]

I have used both the KG software and the TormekCalc and also tested to measure on the FVB. For this I took very accurate measurements, with also accurate large squere, with a guaranteed 90 degree angle.
I have also sharpened a knife on those values based on the settings I found.

In the end I find measuring the USB directly on the wheel the most accurate method.  This can be done with the TormekCalc, but also with the tool of cbwx34. The results of the calculation are the same.

This measurement is:
- Accurate, because you are least affected by possible multiple measurement deviations, which you have to set. This includes not only distance measurements, but also 90-degree angles.

- Simple, because it does not matter which FVB you use. Only the distance to the wheel counts.

I did adapt the depth gauge slightly, to hit the wheel at the right place. See photo's.

I like your modification... it kinda supports what I posted earlier that using the wider side of a digital caliper worked better than the narrow depth gauge (measuring to the wheel anyway).

Ken,

Thank you.
By measuring on the FVB, you have to measure very accurately, to tenths of millimetres and the exact 90 degrees of a carpenter's square. Otherwise the setting will be imprecise.

But the risk is that you can get lost in an idea of accuracy that is not realistic for the grinding process.
The tools' calculations encourage this line of thinking, as they (understandably) calculate to 2 decimal places.

To be clear, I have a lot of sympathy for the developers of the calculation models. Please continue to do so.

Wim

I think either method works well... I just prefer measuring to the wheel, mainly because it's easier to adapt to just about any setup, as well as the other reasons you mentioned.  I've said it before though, that too much was made out of being "super accurate"... measuring in 100ths of a mm is not necessary with either method. 

My main reasons for using a calculator is that it works better & easier vs. the Anglemaster (more accurate and consistent), and it automatically accounts for blade taper.  But if one wants to measure to the casing or top of the FVB, just be consistent in how it's done.  (Be consistent with either method).  My .02.

[Ken S]

Wim,

I understand your desire for accuracy. (I feel the same way.) However, I am reluctant to use the word "exact" with any measuring tool. Even the most accurate squares made by a world class toolmaker like L S Starrett Co. are not "exact". They are sold with tolerance limits. These can be very minute, often expressed in plus or minus ten thousandths of an inch or metric equivalent.

A computer device can calculate far beyond the limits of mechanical tools. The mechanical tools are also hampered by the skill of the operator. That is why I like the consistency of gage blocks. A gage block retains the same dimensions no matter how often it is used. I am talking "within reason". For sharpening a knife, I really don't care if "15° is really 15°5', as long as it is reasonably consistent.

I think certain tool functions are really after thoughts. The skinny, wobbly depth rods of four function calipers seem that way to my. They may work fine to measure the depth of a half inch drilled hole. Measuring Distance with an BVB seems like a stretch to me. (I also happen to think that the Anglemaster works very well with chisels and planes, but less well with knives.)

I believe good sharpening should be up to standards. The standards should fit the work.

Ken

[3D Anvil]

I was definitely guilty of obsessing over absolute accuracy when I first got my Tormek (not long ago!).  As others mentioned, it's just not that important in view of the fact that almost every sharpening will result in greater variation than you get from missing a measurement by fractions of a mm.  That's because the Jig isn't locked in, and because, even if it was, there is going to be angle variation with any blade that isn't ruler-straight, simply because the angle changes as the contact point travels up and down the stone, however slightly it moves.

Still, I like to be as precise as *reasonably* possible to minimize metal loss with repeated sharpenings.

[RichColvin]

Adam,

I am a fan of precision, not accuracy (https://www.diffen.com/difference/Accuracy_vs_Precision).  The Tormek is an excellent tool for repeatability and that is far more important to me as I resharpen often.

In his review of Simon Winchester's The Perfectionists: How Precision Engineers Created the Modern World, James Gleick writes for the New York Review of Books... precision involves an ideal of meticulousness and consistency, while accuracy implies real-world truth. When a sharpshooter fires at a target, if the bullets strike close together—clustered, rather than spread out—that is precise shooting. But the shots are only accurate if they hit the bull's eye. A clock is precise when it marks the seconds exactly and unvaryingly but may still be inaccurate if it shows the wrong time.

To me, the exactness of an angle is less important than that is always the same and I can count on that. 

Rich

[WimSpi]

Adam,

I am a fan of precision, not accuracy (https://www.diffen.com/difference/Accuracy_vs_Precision).  The Tormek is an excellent tool for repeatability and that is far more important to me as I resharpen often.

In his review of Simon Winchester's The Perfectionists: How Precision Engineers Created the Modern World, James Gleick writes for the New York Review of Books... precision involves an ideal of meticulousness and consistency, while accuracy implies real-world truth. When a sharpshooter fires at a target, if the bullets strike close together—clustered, rather than spread out—that is precise shooting. But the shots are only accurate if they hit the bull's eye. A clock is precise when it marks the seconds exactly and unvaryingly but may still be inaccurate if it shows the wrong time.

To me, the exactness of an angle is less important than that is always the same and I can count on that. 

Rich

That is a beautiful thought. My first carpentry teacher told me 52 years ago in the subject of tool learning: "the first 89 degrees you do with your square and the last degree you do with your eye".

I didn't understand it then, but I did later:
Don't just rely on your measuring tools, however good they may be. Think carefully about what and how you measure and accept that practice will always be different.

[cbwx34]

...
Still, I like to be as precise as *reasonably* possible to minimize metal loss with repeated sharpenings.

It is true that duplicating past sharpening(s) minimizes metal loss, but the best advice I adopted to minimize metal loss was from Ben Dale (who invented the Edge Pro sharpener).  Learn a method to maintain the edge... strop, ceramic rod, etc.  I can maintain an edge for quite a while.  For example, my kitchen knives haven't been sharpened in a couple years now (to be fair, I'm not a big cook), but maintained with a fine ceramic.  Same for my EDC, which does see more use... (it's maintained with a fine diamond stone).

Only when that quits working, or damage, etc., then it's time to re-sharpen, to reset the edge.  Of course it depends on use... YMMV.

[3D Anvil]

Adam,

I am a fan of precision, not accuracy (https://www.diffen.com/difference/Accuracy_vs_Precision).  The Tormek is an excellent tool for repeatability and that is far more important to me as I resharpen often.

In his review of Simon Winchester's The Perfectionists: How Precision Engineers Created the Modern World, James Gleick writes for the New York Review of Books... precision involves an ideal of meticulousness and consistency, while accuracy implies real-world truth. When a sharpshooter fires at a target, if the bullets strike close together—clustered, rather than spread out—that is precise shooting. But the shots are only accurate if they hit the bull's eye. A clock is precise when it marks the seconds exactly and unvaryingly but may still be inaccurate if it shows the wrong time.

To me, the exactness of an angle is less important than that is always the same and I can count on that. 

Rich

Excellent point, although to some extent I think the two things are joined at the hip.  For this very reason, I keep almost all of my knives at 15 dps.  The Tormek (and CB's software) allows me to quickly and accurately set the machine up for a precise 15° bevel, so if a knife does need a touch-up, it's generally no more than one or two passes per side on a fine wheel to raise a very minimal burr. 

I do strop in between sharpenings, but I like to keep my knives unreasonably sharp.