GRS EasyGraver Sharpening Fixture Review?

[jamiefeinstein]

notice the 120 fixture holes (the closest to the top) are for the initial shaping of the bottom of the graver.... why would the 120 be closer together than the 105?

 

[jamiefeinstein]

View attachment 53443
The holes are further apart from the center line on the 105 than the 120.... it's like this on GRS website too!

 

[AllenClapp]

I see what you mean. When you visually look at the top of the 120, it LOOKS like it would create a lesser vee angle than the 105. However, you need to think of it differently. You need to think of how much metal needs to be removed to leave the desired vee angle. The 120 rotates less on each side to shape the graver than does the 105. Therefore, the 120 grinds less metal away and leaves more metal that is not removed than the 105 and, thus, leaves a wider vee angle of unremoved metal. If you remove 45 degrees on a side, you will be left with 45 degrees of metal on that side and produce a total 90 degree shaped vee angle. If you remove 30 degrees on each side, you will be left with 60 degrees of metal on that side and produce a total 120 degree shaped vee angle. If you look at the results of shaping a new graver with each, you will see that the 120 degree graver has a wider vee than the 105.

 

[jamiefeinstein]

I see what you mean. When you visually look at the top of the 120, it LOOKS like it would create a lesser vee angle than the 105. However, you need to think of it differently. You need to think of how much metal needs to be removed to leave the desired vee angle. The 120 rotates less on each side to shape the graver than does the 105. Therefore, the 120 grinds less metal away and leaves more metal that is not removed than the 105 and, thus, leaves a wider vee angle of unremoved metal. If you remove 45 degrees on a side, you will be left with 45 degrees of metal on that side and produce a total 90 degree shaped vee angle. If you remove 30 degrees on each side, you will be left with 60 degrees of metal on that side and produce a total 120 degree shaped vee angle. If you look at the results of shaping a new graver with each, you will see that the 120 degree graver has a wider vee than the 105.

Thank you for your patient response. I feel a little silly how hard it was for me to wrap my brain around this whole issue. I have a couple of sharpening fixtures / templates which all seem pretty straight forward in comparison and after I sharpened a graver using the 120 easy graver I felt (even after viewing / comparing under magnification) that the angle was sharper than my other templates that are marked with a lesser angle...Steve Lindsay's 116 for example.