Is this proof the variable thickness stone adapter works?

[phillyjudge]

Or did I do it wrong, or both?

 

I mounted a knife in the vise, chose an angle that was appropriate which measured at 16.5° both before and after referencing it on the variable thickness stone adapter. I started at 100, then 200 grit.

When I switched to the 400 grit stone, I re-referenced both sides and they both came out to about 15.9°.

 

Is it fair to say that as long as the new grip and paddles are referenced exactly to the adapter, the measured angle does not make a difference?

Or is my technique off. Using the sharpie technique, the knife edge looks OK?

[phillyjudge]

when I use the 800/1000 grit, it was back to 16.5 degrees.

Should EACH grit be re- referenced?

 

[phillyjudge]

AND, ….how much variability is introduced by the angle cube itself? I wiggle and jiggle it until I have a consistent read out, but, it, too can change even though everything is locked down tightly. I am wondering where more error is introduced–re measuring from grit to grit to grit or the error in referencing each new grit to the VTSA…

[tcmeyer]

Assuming that you are using the VSTAs properly, I suspect that the differences you are measuring are caused by how you are holding the AngleCube and the handle.

Used properly, the VSTAs won’t produce much more than 0.1 degree in difference from one stone to another and every stone referenced to the VSTA should be within about 0.1 degrees of every other stone.  I am so confident in this that I never use my AngleCube after the initial setup unless I see something has gone out of whack.  For instance, on two occasions, I’ve had my microadjust come loose and the rubber finger cot I had installed to protect my spherical joint was twisting the micro-adjust with each stroke.  But these were the only times my angle has gone wacky.

Now, as to AngleCube errors…

Since I went to the DXL360, I’ve learned that these devices are very sensitive to vibration and can be made much more stable by holding the stone tightly against the edge.  Usually, the ‘Cube will settle down to a final reading in about 3-5 seconds.  If you really want to be accurate, take at least three readings and average them out.  Yes, tapping the ‘Cube while holding the stone tightly against the edge will help to jostle the Cube into a more correct reading.  FWIW, I once ran a long series of tests using my VSTAs and found that averaging six sets of readings is as accurate as taking ten readings.

When you take such a measurement, always hold the stone in the same position.  Never apply pressure to the stone above the edge.  You can induce errors of more than one degree by taking one reading with pressure applied above the edge vs the second below the edge.  The clearances between the bore and the rod are enough to cause this.  And a loose spherical joint (as in my el cheapo bronze joints) can contribute to this.

Consistency is all-important, whether you are referencing your stone to the VSTA or measuring the angle or actually taking strokes in the sharpening process.  Practice makes perfect, but one has to know what trouble to avoid.  I hope this helps.

 

2 users thanked author for this post.

dulledge, M1rrorEdge

[phillyjudge]

Thank you so much. I appreciate it. So use the adapter as a reference And go on from there!

[Author]

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