I use the Carter and Son sharpening chart for my turning tools. For gouges, the Wolverine jig is set at 23 degrees and a 2" projection, with the angle varying depending on how you want to configure the tool. I have set up my bowl gouges at 50 degrees. My spindle gouges range from 45 degrees to 35 degrees for detail gouges. Recently, I ground a 1/2" gouge to a 40/40 grind using Ron Brown's jig. After using the 40/40 grind gouge on a couple of projects, I ground another 1/2" bowl gouge to a 40-degree angle using the Carter and Son grinding chart. The profile of the grind was a bit different, but the gouges both worked reasonably well. I don't think that I could have differentiated between the tools if I didn't know which one I was using from the color of the handle.
After comparing the 40/40 grind to the 50-degree grind, I came away with the conclusion that the 50-degree grind is better for working inside a bowl. It is better for shear scraping too. The 40/40 worked fine inside a bowl, as until transitioning at the bottom of the bowl where it was more difficult to keep riding the bevel than it was for the 50-degree grind. Granted, I could have cut most of the inside of the bowl with the 40/40 and cleaned up the side/bottom transition and bottom with a bottom-feeder gouge, which I often end up doing.
Honestly, I could not find the magic in the 40/40 grind. It is not that it does not do the job. Other than being a little grabby on some cuts, it cuts well. I just don't see the advantage of the 40/40 grind over my 50 degree grind. I suspect that I am missing something.
After comparing the 40/40 grind to the 50-degree grind, I came away with the conclusion that the 50-degree grind is better for working inside a bowl. It is better for shear scraping too. The 40/40 worked fine inside a bowl, as until transitioning at the bottom of the bowl where it was more difficult to keep riding the bevel than it was for the 50-degree grind. Granted, I could have cut most of the inside of the bowl with the 40/40 and cleaned up the side/bottom transition and bottom with a bottom-feeder gouge, which I often end up doing.
Honestly, I could not find the magic in the 40/40 grind. It is not that it does not do the job. Other than being a little grabby on some cuts, it cuts well. I just don't see the advantage of the 40/40 grind over my 50 degree grind. I suspect that I am missing something.