Edge Tester - 3D

[DudeAbides]

The Edge on up BESS number is actually already grams of force, based on cutting approximately a 0.2mm fluorocarbon fishing line.

If you get yourself some 0.2 fluorocarbon line, that could be your direct comparison.

I did not realize that the BESS number was grams of force. It was my understanding that it represents the radius of the apex of the cutting edge in nanometers. According to KnifeGrinders.com:

“BESS is an acronym for the Brubacher Edge Sharpness Scale – an international standard of quantifying sharpness.
BESS-calibrated edge sharpness testers show edge apex radius in nm.
E.g. DE safety razors score 50 on the tester and have 50 nm apex radius, i.e. 100 nm or 0.1 micron edge apex width.”

This being the case I wonder if I can come up with the jig that will measure pulling force rather than pushing force for the cutting. Then I can use my archery scale.

I like your force meter. Very cool. I’m trying to do most of this on the cheap with equipment that I already have.

On your alternate design where the meter is laying flat it looks like somehow you were also going from pushing to pulling. But I don’t really see how the mechanism is connecting the test line to the sensor bar.

 

[777 Edge]

On your alternate design where the meter is laying flat it looks like somehow you were also going from pushing to pulling. But I don’t really see how the mechanism is connecting the test line to the sensor bar.

Yes, my force meter measures both pull and push so my alternative design is based on how some eastern European meters test - by testing with the meter in pull force setting to measure a push cut on the line.

I designed a head that screws onto the force meter with a pinch thumb screw for the line. After pinching the line, I run the line to the second pinch thumb screw (attached to a small vise). Then I turn on the Force meter, and pre-adjust the tension of the line to an exact nominal value with the vise (I'm still experimenting but about 20g of tension seems good). After this, I zero the force meter and set it to peak saving value before cutting the line.

This way, the same force meter can be used to pre-tension the line to an exact value, and then also measure the cut.

 

[777 Edge]

I did not realize that the BESS number was grams of force. ....
E.g. DE safety razors score 50 on the tester and have 50 nm apex radius...

That "50" value is a push cut value of 50g for a common DE razor blade.

FYI, a Feather brand DE razor blade cuts about 25-30g.

All the values in their charts are cut force in grams.

 

[DudeAbides]

That "50" value is a push cut value of 50g for a common DE razor blade.

FYI, a Feather brand DE razor blade cuts about 25-30g.

All the values in their charts are cut force in grams.

So that nanometer stuff is all just marketing? It kind of makes sense. That saves me a lot of trouble.

That’s very clever using a force meter as opposed to a scale. I didn’t even think of that. But force meters are always going to have a peak measurement whereas many scales do not. You can buy a 2 Newton meter that looks pretty much like the one you’re using for $50 that has a accuracy of 1%. That’s going to translate into 1.02g of accuracy. This is on par with the most expensive version of the Edge Up. And your new jig is a completely original design. I have to say I like it and it is pretty inspired.

Can you give me a ballpark estimate of what the value of the five 3-D printing just like that would be? I guess what would you charge your neighbor for making one of those, that would include the rae material and labor cost. I’m just trying to get a ballpark estimate of the cost of a set up for someone who doesn’t have their own 3-D printing facility. Many cities have maker spaces where one can join and have access to their 3-D printing and CNC equipment.

I always get a fair amount of satisfaction of doing something myself as well.

It’s been enjoyable to see the many ways in which people are trying to measure what has always been a fairly ineffable quantity around here. Thank you for your efforts and your willingness to share your designs with the community. I think you have demonstrated that there is a legitimate viable alternative to a commercial BES tester that is in many ways, superior to the original.

 

[cudgee]

So that nanometer stuff is all just marketing? It kind of makes sense. That saves me a lot of trouble.

That’s very clever using a force meter as opposed to a scale. I didn’t even think of that. But force meters are always going to have a peak measurement whereas many scales do not. You can buy a 2 Newton meter that looks pretty much like the one you’re using for $50 that has a accuracy of 1%. That’s going to translate into 1.02g of accuracy. This is on par with the most expensive version of the Edge Up. And your new jig is a completely original design. I have to say I like it and it is pretty inspired.

Can you give me a ballpark estimate of what the value of the five 3-D printing just like that would be? I guess what would you charge your neighbor for making one of those, that would include the rae material and labor cost. I’m just trying to get a ballpark estimate of the cost of a set up for someone who doesn’t have their own 3-D printing facility. Many cities have maker spaces where one can join and have access to their 3-D printing and CNC equipment.

I always get a fair amount of satisfaction of doing something myself as well.

It’s been enjoyable to see the many ways in which people are trying to measure what has always been a fairly ineffable quantity around here. Thank you for your efforts and your willingness to share your designs with the community. I think you have demonstrated that there is a legitimate viable alternative to a commercial BES tester that is in many ways, superior to the original.

Thanks for your post, on seeing your archery tester, i have one on the way as well as some .02 flurocarbon fishing line all for under $20US. I am not in a financial position to be purchasing any of the recognised edge testers just far to expensive for me, but i am a knife equipment junkie and your system will give me something to get a rough idea of how sharp my edges are. Thanks again and have a good weekend. .

Hope you can get your 3-D printed tester worked out. .

 

[777 Edge]

So that nanometer stuff is all just marketing? It kind of makes sense. That saves me a lot of trouble.

That’s very clever using a force meter as opposed to a scale. I didn’t even think of that. But force meters are always going to have a peak measurement whereas many scales do not. You can buy a 2 Newton meter that looks pretty much like the one you’re using for $50 that has a accuracy of 1%. That’s going to translate into 1.02g of accuracy. This is on par with the most expensive version of the Edge Up. And your new jig is a completely original design. I have to say I like it and it is pretty inspired.

Can you give me a ballpark estimate of what the value of the five 3-D printing just like that would be? I guess what would you charge your neighbor for making one of those, that would include the rae material and labor cost. I’m just trying to get a ballpark estimate of the cost of a set up for someone who doesn’t have their own 3-D printing facility. Many cities have maker spaces where one can join and have access to their 3-D printing and CNC equipment.

I always get a fair amount of satisfaction of doing something myself as well.

It’s been enjoyable to see the many ways in which people are trying to measure what has always been a fairly ineffable quantity around here. Thank you for your efforts and your willingness to share your designs with the community. I think you have demonstrated that there is a legitimate viable alternative to a commercial BES tester that is in many ways, superior to the original.

Thanks!

Yes, these force meters are immensely accurate and the best part is the fact that it can do both pull and push, it can set a zero reference and save peak values. In my opinion this is a perfect solution for edge testing.

This is actually part of a project I'm working on with Gritomatic.com, so they may in the near future be selling these for a very fair price. It will be up to them.

The very first post in this thread has one of my earlier, free designs that should also work well with a force meter.

Hopefully they also decide to make my laser edge Goniometer available some time soon. That will also be a very cheap yet accurate alternative to the expensive Goniometers.

 

[DudeAbides]

The very first post in this thread has one of my earlier, free designs that should also work well with a force meter.

Hopefully they also decide to make my laser edge Goniometer available some time soon. That will also be a very cheap yet accurate alternative to the expensive Goniometers.

I have been using a shotgun laser in a vice that bounces off the blade flat on a table and projects onto a vertically standing protractor, seems to work okay, but it takes a small table and it’s not really a device, it’s several loosely affiliated pieces. I would love to see your Goniometer. There are limited options in this category and in sharpness testing so it’s good to see somebody with a mind for engineering who is working on other options. This is precisely what led to me to this thread to begin with.

if you decide to do a Kickstarter, I’m in.

 

[DudeAbides]

Thanks for your post, on seeing your archery tester, i have one on the way as well as some .02 flurocarbon fishing line all for under $20US

This is precisely why I posted my humble solution. I figured there were people out there who didn’t have the money for fancy stuff but still had a desire to measure their blades.

Now all you need is a coat hanger wire and some heat shrink tubing, and you can double that as a trigger pull gauge if you happen to be a gun owner as well.

Hell, you can even use the loop of Paracord. There’s nothing that says the trigger puller has to be rigid.

 

[ElementalBreakdown]

Someone posted the file for a 3d printed version here, my buddy made one for me on his 3d printer.
I will link it if anyone wants me to dig it up.

 

[Dull-edge]

You can't be serious saying that the Edge On Up BESS tester is "expensive". A quality lab scale with memory costs not much less. For consistency you need a platform and fulcrum.
For the sharpness score to be meaningful to others, the instrument must be calibrated to the BESS sharpness scale.
The Feather DE razor should score 30 g. as you can see here https://www.refinedshave.com/razor-blade-sharpness-testing/

For calibration the instrument needs a firmware chip. See the 2 calibration buttons on the panel - the ones with the screw head symbol?

The PT50 BESS tester is a system, not just test line and a scale.
The PT50B updates the display every 100ms, the PT50A every 40ms. The average kitchen scale does so every 1.5 seconds. That's 15 times slower than the PT50B, and because of that the reading you see is always higher than what we see on the BESS testers.
Speed is critical to accurate measurements in that we want to capture, as closely as possible, the actual moment of severing the test line.

A fishing line has inconsistent diameter along its length, and because of that the test score varies even when measured on the BESS tester; contrary to that the BESS certified test media has a highly consistent diameter.