I built a homemade fixed arm sharpening jig and a sliding arm fixture which definitely improved my sharpening and turning abilities but it seems that to control the angle of the nose and wings that I need a movable arm jig.
Lyle Jamieson and another well known turner explained that the basket length from the grinder set the angle for one, the angle of the arm set the angle for the other. Where it gets confusing is that one said that the nose angle was set by the distance the basket was from the wheel and the wing angle was set by the angle of the arm. The other turner said exactly the opposite! Which is correct, A or B or neither completely accurate?
A: nose angle set by distance of bucket from grinding wheel, wing angle set by jig arm angle.
B. nose angle set by jig arm angle and wing angle set by distance of bucket from wheel.
To add to my confusion once Lyle had the jig and bucket set up for one grind, he said just shimming the bucket, effectively changing the bucket location, made the angles correct for other grinds. While I can see how moving up on the wheel would adjust the angles, it seems likely that it would still require some tweaking of the jig arm to have both nose bevel and wing bevel identical again.
Which leads to the final question: What is the baseline to measure wing angle? Is it measured in the direction of the grind, in relation to the centerline of the shaft of the gouge, in relation to the flute, or something else?
reference video: http://www.youtube.com/watch?v=0zUph9zEjck
Jig set-up starts at about 3:30.
Thanks for any enlightenment!
Hu
Lyle Jamieson and another well known turner explained that the basket length from the grinder set the angle for one, the angle of the arm set the angle for the other. Where it gets confusing is that one said that the nose angle was set by the distance the basket was from the wheel and the wing angle was set by the angle of the arm. The other turner said exactly the opposite! Which is correct, A or B or neither completely accurate?
A: nose angle set by distance of bucket from grinding wheel, wing angle set by jig arm angle.
B. nose angle set by jig arm angle and wing angle set by distance of bucket from wheel.
To add to my confusion once Lyle had the jig and bucket set up for one grind, he said just shimming the bucket, effectively changing the bucket location, made the angles correct for other grinds. While I can see how moving up on the wheel would adjust the angles, it seems likely that it would still require some tweaking of the jig arm to have both nose bevel and wing bevel identical again.
Which leads to the final question: What is the baseline to measure wing angle? Is it measured in the direction of the grind, in relation to the centerline of the shaft of the gouge, in relation to the flute, or something else?
reference video: http://www.youtube.com/watch?v=0zUph9zEjck
Jig set-up starts at about 3:30.
Thanks for any enlightenment!
Hu