Angle cube seems to vary quite a bit…

[Scott]

Not to beat a dead horse, but I was a bit late to the party when it was discovered that the screws that locked the angle guide arms in place did not seat into the dimpled bar under the riser. I sort of think that this is at the core of this problem since the guide arms are being subjected to different dresses and vibrations with each stroke and since they are just depending on friction against the flat part of that steel bar instead of sitting inside a dimple or cup to hold it in place it is inevitable that it will drift a bit this way or that. So that is why between each stone I find that the angle is off enough to effect the flatness and accuracy of the bevel on the blade under the apex.

So, I think that this should be remedied when Clay gets the new guide rod hardware out to lock those arms in place more securely. I think once in effect, when you set the guide rods, you can be confident that they will cause the stones to strike and drag over the blade at a consistent angle each time, assuming the thickness of the stone is within a tiny fraction of the others. As the diamond stones are.

At least I hope this is the case.

[Phil Pasteur]

You are beating a dead horse!

Just as a data point. I have not used the dimpled side of the rod ever since I got my angle cube. Way over a year and a hundred knives ago. I don’t have issues with the sliders wandering. Only about three months ago did I think to file the ends of the screws flat. This reduces the torque required on the set screws to keep the slider in place, but not dramatically.

While I was going through my little sharpening routine over the last couple of days I di notice somethng about my angle cube. I could change the fine adjuster over maybe a turn and my angle reading would not change. I would move the angle cube away from the stone and reset it, the reading would change in excess of 0.20 degrees…sometimes 0.3..
In other words the angle cube requires a bit of finessing to work as well as it can. I mentioned that I usually just check angles with the coarse diamonds, then with the Choseras (once) then with the strops (once). For the last excercize I checked everytime I flipped the stones or changed them. I would get a couple of tenths or so difference everytime! I would carefully make adjustments until I was exactly at 18 degrees..and hold the cube in place for 20 to 30 seconds to make sure that it stabilized. Sharpen away and check again when I flipped the stones…. then start cursing because the reading was different….

I Know that nothing slipped. I was cranking the screws down with pliers…!!! I have purple locktite on the threads, the arm joints have almost no slop. That leaves two possibilities (as far as I can see), the stones actually are different thicknesses to the extent that causes the difference, or my placement of the stones along the length of the blade was not prceise enough.

In any case, as was discussed before, a couple tenths of a degree is really noting to obsess about. In my experience, new screws, old screws, whatever screws, you will likely see differences in readings of this magnitude… IF you are worried enough to check often enough.

If you have the black screws, until you get the update, I would bet that applying a bit of the purple locktite and cranking down a bit on them will be plenty to keep your sliders from moving enough to bother anything. Of course, if it still worries you, get some thumbscrews to fit and put them in the back threaded holes. Even if you are sure your sliders are not moving… the angle cube will surely drive you to distraction if you let it.
🙂

Phil

[Scott]

Thanks Phil,
I can always count on you to put things in the proper perspective. I guess the truth will be in the actual user experience when I am able to switch out the screws to see if there is less movement. I only bring this up because we (I) are (am) dealing with scratches that are microscopic and in attempting to get that mirror finish with as few visible scratches to my eye possible. When the angle changes, even 0.2 or 0.3 degrees, it can have an effect.

Anyway, as always thanks for your response. I appreciate that you thought it was significant enough to take the time and spend the energy to experiment on your own system to respond.

[wickededge]

A couple things to note about the Angle Cubes:

• They have an error percentage of +/- .2 degrees.
• They vary in their readings within that range routinely and need to be properly ‘settled’ which does take finesse.
• They’re sensitive to being perpendicular to the zero plane from at least one side; in our case, the front and back of the box need to be perpendicular to the plane. If you rotate the cube on the stone so that the numbers are facing somewhat up or down, you’ll see a significant difference in angle. I shoot for having the stone right in line with the vise jaws and the edge of the bevel of the cube aligned to the edge of the stone. If I’m being really OCD about it, I’ll use a square against the back plate of the cube to be sure.

-Clay

[Phil Pasteur]

Thanks Clay…

Also Scott. Keep in mind that I usually am not that anal about the cube… I was trying to make that Dmascus Mule as close to perfect as I could get it.
I usually, as mentioned check when first setting up the diamonds, then with the choseras (keep in mind that those are not machined parts and wear at different rates…so I would not be surprised to see angles +/- 0.5 degrees) then before the strop series (again the leather is not uniform, much less the “roo and nanocloth). I get great edges doing that. They cut well and are very pretty as well.

You can obsess about it, but as Clay mentions, you are running up against the accuracy of the device when fretting about .2 degrees (worst case you could be off by 0.4 degrees and never even know it)… If this is Varying quite a bit… to you, you need a more accurate device before we start looking at inaccuracies in the WEPS as being the culprit.

If you find one, let me know… I will probably buy one !!:)

Here is an interesting quote for you:

“Recall that two values that are different, yet are still within the stated tolerance of the measuring device,cannot reliably be distinguished from each other.”

http://www.gia.edu/diamondcut/pdf/4_05_RDR_pg183_185.pdf

Take a read of it…interesting stuff.

Phil

Thanks Phil,
I can always count on you to put things in the proper perspective. I guess the truth will be in the actual user experience when I am able to switch out the screws to see if there is less movement. I only bring this up because we (I) are (am) dealing with scratches that are microscopic and in attempting to get that mirror finish with as few visible scratches to my eye possible. When the angle changes, even 0.2 or 0.3 degrees, it can have an effect.

Anyway, as always thanks for your response. I appreciate that you thought it was significant enough to take the time and spend the energy to experiment on your own system to respond.

[Phil Pasteur]

Hey Clay,
Speaking of the Angle cube….
You mentioned having the claibration procedure for the angle cube at one point some time back. Do you still have it.
I ran accross it one time and actually did it… now I can’t find it. If you do have it, could I get a copy?
Please.

Phil

A couple things to note about the Angle Cubes:

• They have an error percentage of +/- .2 degrees.
• They vary in their readings within that range routinely and need to be properly ‘settled’ which does take finesse.
• They’re sensitive to being perpendicular to the zero plane from at least one side; in our case, the front and back of the box need to be perpendicular to the plane. If you rotate the cube on the stone so that the numbers are facing somewhat up or down, you’ll see a significant difference in angle. I shoot for having the stone right in line with the vise jaws and the edge of the bevel of the cube aligned to the edge of the stone. If I’m being really OCD about it, I’ll use a square against the back plate of the cube to be sure.

[Geocyclist]

Good point Phil about the values being within the tolerance. My 2 cents: there no point worrying about the angle any more than to the nearest 0.5 degrees. Smaller than that and you are getting close to the 0.2 working accuracy.

Getting down to brass tax: IF the cube was accurate to 0.000001 degrees, could you tell one side was off by 0.1? Based on how the edge bevel is? I think not?

I have noticed the phenomena about the cube, sometimes you just have to take it off, turn it a bit and put it back on to get a good measurement.

[Mikedoh]

Is there more to calibrating it than rezeroing it on your work surface each time?

[wickededge]

Hey Phil,

I’ll see what I can dig up. It’s been a while and my memory is rusty.

-Clay

[cbwx34]

Are you talking about this?

http://wickededgeusa.com/index.php?option=com_kunena&func=view&catid=2&id=363&Itemid=63

[Phil Pasteur]

Good article, but no.
I just shot a note off to iGaging asking for the procedure. Lets see what I get back, if anything.
If I get the procedure I will scan it and post it.

Phil

[wickededge]

Good article, but no.
I just shot a note off to iGaging asking for the procedure. Lets see what I get back, if anything.
If I get the procedure I will scan it and post it.

Phil

They’re usually pretty responsive there. I also sent an email to them this morning.

-Clay

[wickededge]

I got the recalibration instructions back from iGaging. Here they are: Re-calibrating your digital angle gauge. There is a permanent link to the file on the Downloads page, accessible from the Resources tab.

-Clay

[Phil Pasteur]

Thanks Clay.
I just could not remember the button sequences to get it into calibration mode. Now I have that.
Of course the requirement to have soemthing level to 0.02 degrees is a problem.
I used a metal plate that I had leveled with another device that claims 0.1 degree accuracy..
Who knows, but I have no granite surface plate available to me anymore…

My cube will show exactly 90 degrees on either side after zeroing it. Probably as good as it gets.

Thanks for posting that. I have still not heard back from the good folks at iGaging.

Phil

[Anthony Yan]

I’ve been using the Wixey Digital Angle Gauge, which is very similar to the iGaging Angle Cube. On paper, the Wixey is supposed to have an overall accuracy of 0.1 degrees, and a repeatability of 0.1 degrees. It has a resolution of 0.1 degrees.
http://www.wixey.com/anglegauge/index.html#wr300

I have a small granite surface plate, and a sine bar, so I may try to test its accuracy.

There are very high accuracy digital inclinometers, but they are expensive. The one below only measures a limited range of +/- 20 degrees, but has very high accuracy (0.003 degrees).
http://www.digipas.com/DWL-3500.php

Alternatively, you might be able to rig something up with a machinist’s spirit level (also called an engineer’s level) which is basically a very precise bubble-level with liquid. You would need something like a sine bar, gauge blocks, or angle gauge-blocks, and/or a micrometer. You can buy non-digital engineer inclinometers which are already rigged up this way, but they’re very expensive (several hundreds of dollars). Of course, at this point, you’re probably insane. 🙂 Have I thought about this? Yes. 🙂 I got quite curious about general metrology, and have been reading up on it and looking at company websites that sell metrology products.

In terms of cutting performance, I probably wouldn’t notice a +/-1 degree difference.

Sincerely,
–Lagrangian

[Author]

Posts