The turning club I belong to, the Vermont Woodturners Guild, has a shop with three grinders equipped with Wolverine grinding jigs. We have two of the original Vari Grind tool holders with adjustable legs. I volunteered to try to make things consistent for grinding bowl gouges and spindle gouges to match what had been agreed on by the club gurus.
I started by checking that the Wolverine bases were at a consistent height below the wheel centers, and they were close enough that I only had to shim two of the six by 1/16". (Oneway specifies that the distance should be 6 1/4" to 6 1/2"). Then I took a sample bowl gouge from the drawer and set the leg angle and basket protrusion from the front of the wheel to match the existing grind, checking several other gouges to make sure I wasn't dealing with an oddball. At that point I cut a dowel to fit between the basket socket and the wheel face and drilled a 7/64" hole through the leg and body of a Vari Grind jig, intending to tap it for a 6-32 screw. Naturally, the small tap broke, so that jig is fixed forever unless somebody is ambitious enough to remove the tap. I repeated the process for spindle gouges and just drilled through that tool holder and left a spare drill bit for realignment in case someone makes adjustments. I made two sets of dowels for the basket settings and labelled them and the tool holders "BOWL" and "SPINDLE". If someone comes up with the colored sticky dots to match the ones on the tools the system will be almost foolproof. I don't know if the settings are optimal but at least they will be consistent.
When I got home I looked at my own sharpening station. I have a similar setup and have been using an original Ellsworth jig for the two 5/8" spindle gouges that are my workhorses, but really hadn't paid much attention to the angles I was putting on the tools. Ellsworth's hand-drawn instructions call for a 2" gouge protrusion from the tool holder with the basket 4" below and 7" in front of the wheel center. My Wolverine base was too low by those specs by an inch so I decided to block it up temporarily to see how the grind differed from what I had been doing. I had been working with a 55* nose bevel and about 50* on the wings, whereas the "official" setup gave a 60* nose bevel and 45* on the wings, as close as I can measure it. I restored the Wolverine base to its original position and adjusted the basket and leg angle to match the Ellsworth original grind. I doubt it will make a great deal of difference, but the steeper nose angle should help in the bottom of deep bowls and the more acute wing bevel may help with some woods when cutting between the nose and wing. The whole exercise was instructive in terms of seeing the inter-relation of the three parameters that can be adjusted with the Vari Grind.
One thing I have found at the club is that people rely on the jigs to produce a properly working tool without using judgment and finesse. I often see bowl gouges with a swept-back grind with concave wings, even on parabolic flute shapes that are relatively easy to sharpen properly. I grind most of my tools, including bowl gouges with a 40-40 grind, on a platform with no jig, and I think that is helpful in developing a feel for shaping the tools that can carry over when using a jig.
I started by checking that the Wolverine bases were at a consistent height below the wheel centers, and they were close enough that I only had to shim two of the six by 1/16". (Oneway specifies that the distance should be 6 1/4" to 6 1/2"). Then I took a sample bowl gouge from the drawer and set the leg angle and basket protrusion from the front of the wheel to match the existing grind, checking several other gouges to make sure I wasn't dealing with an oddball. At that point I cut a dowel to fit between the basket socket and the wheel face and drilled a 7/64" hole through the leg and body of a Vari Grind jig, intending to tap it for a 6-32 screw. Naturally, the small tap broke, so that jig is fixed forever unless somebody is ambitious enough to remove the tap. I repeated the process for spindle gouges and just drilled through that tool holder and left a spare drill bit for realignment in case someone makes adjustments. I made two sets of dowels for the basket settings and labelled them and the tool holders "BOWL" and "SPINDLE". If someone comes up with the colored sticky dots to match the ones on the tools the system will be almost foolproof. I don't know if the settings are optimal but at least they will be consistent.
When I got home I looked at my own sharpening station. I have a similar setup and have been using an original Ellsworth jig for the two 5/8" spindle gouges that are my workhorses, but really hadn't paid much attention to the angles I was putting on the tools. Ellsworth's hand-drawn instructions call for a 2" gouge protrusion from the tool holder with the basket 4" below and 7" in front of the wheel center. My Wolverine base was too low by those specs by an inch so I decided to block it up temporarily to see how the grind differed from what I had been doing. I had been working with a 55* nose bevel and about 50* on the wings, whereas the "official" setup gave a 60* nose bevel and 45* on the wings, as close as I can measure it. I restored the Wolverine base to its original position and adjusted the basket and leg angle to match the Ellsworth original grind. I doubt it will make a great deal of difference, but the steeper nose angle should help in the bottom of deep bowls and the more acute wing bevel may help with some woods when cutting between the nose and wing. The whole exercise was instructive in terms of seeing the inter-relation of the three parameters that can be adjusted with the Vari Grind.
One thing I have found at the club is that people rely on the jigs to produce a properly working tool without using judgment and finesse. I often see bowl gouges with a swept-back grind with concave wings, even on parabolic flute shapes that are relatively easy to sharpen properly. I grind most of my tools, including bowl gouges with a 40-40 grind, on a platform with no jig, and I think that is helpful in developing a feel for shaping the tools that can carry over when using a jig.
