Mr. Thomas, thanks for your kind words and also for your confidence I could answer your question. 
I know your precision sharpening equipment quite well. I admire your beautiful handmade instrumentation.
What concerns the claimed precision 0.01°, this is geometrically well possible, but it would require to set the height of the pivot with an accuracy better than 0.05 mm, which is not impossible, but quite challenging. (0.05 mm = 0.002" = 50 microns is a the thickness of human hair)
The other factor influencing the bevel angle accuracy is the distance between the pivot and the point where the edge meet the grindstone. When this distance is not constant along the edge, then also the bevel angle is not constant. 2 mm (0.08") increase in distance between the pivot and the edge will decrease the bevel angle by more than 0.10°. (This is below the limit of resolution for most knife grinders.)
I know that you are aware of it, your custom made Chef overcomes this problem and enables to sharpen "per partes (by parts)" the same bevel angle along very long blades also. Simple, but really very significant improvement, congrats!
In my understanding your instrument works perfectly when the grindstone axis is oriented perpendicularly to the edge. For curved blade sabre it may be true for almost the whole blade while for straight blade the bevel angle gradually slightly decreases towards the tip and towards the heel.
Some role in the answer to your observation may be attributed to mechanical plays in the pivot and other components also.
My laser goniometer, in its current state, measures with an accuracy of some 0.25 to 0.50° only. So to measure several hundredth of a degree is far beyond my possibilities.
Jan
P.S.: It would be interesting to know what happens with the burr when one pass is edge leading while the other edge trailing. Lansky, for example, recommends edge leading direction only.
I know your precision sharpening equipment quite well. I admire your beautiful handmade instrumentation.
What concerns the claimed precision 0.01°, this is geometrically well possible, but it would require to set the height of the pivot with an accuracy better than 0.05 mm, which is not impossible, but quite challenging. (0.05 mm = 0.002" = 50 microns is a the thickness of human hair)
The other factor influencing the bevel angle accuracy is the distance between the pivot and the point where the edge meet the grindstone. When this distance is not constant along the edge, then also the bevel angle is not constant. 2 mm (0.08") increase in distance between the pivot and the edge will decrease the bevel angle by more than 0.10°. (This is below the limit of resolution for most knife grinders.)
I know that you are aware of it, your custom made Chef overcomes this problem and enables to sharpen "per partes (by parts)" the same bevel angle along very long blades also. Simple, but really very significant improvement, congrats!
In my understanding your instrument works perfectly when the grindstone axis is oriented perpendicularly to the edge. For curved blade sabre it may be true for almost the whole blade while for straight blade the bevel angle gradually slightly decreases towards the tip and towards the heel.
Some role in the answer to your observation may be attributed to mechanical plays in the pivot and other components also.
My laser goniometer, in its current state, measures with an accuracy of some 0.25 to 0.50° only. So to measure several hundredth of a degree is far beyond my possibilities.
Jan
P.S.: It would be interesting to know what happens with the burr when one pass is edge leading while the other edge trailing. Lansky, for example, recommends edge leading direction only.