Post by Pete on Mar 19, 2020 19:42:23 GMT
So after watching Stuart Batty on youtube last night, where he particularly extolled the Robert Sorby bowl gouge with it's parabolic flute, then made several trips to the sharpening station allowing me a good look at how he had it marked up, and how to produce the grind, I decided I wanted to do it on the ProEdge.
I suspect I have now invalidated my guarantee, drilling holes in tools is not normal! but that is what I have done! on the inner range of holes there is space for an extra hole at 40° (third one down on inside track in the photo, I did draw a circle round it with marker pen but 3rd one down is probably easier to spot!)
I suspect that Sorby use an imperial drill on the original machining as it was bigger than 7.5mm and a smidgen smaller than the 8mm drill bit I used. To work out where to drill I simply used my digital angle finder, took a reading at the 35° and 45° existing positions then clamped it up at 40° to mark the new hole position. If you are inspired to copy this idea, don't be tempted to drill through the moving plate, that bit is threaded!!
I then measured 40° from each side of the belt drew a pencil line on the table and coloured in the corners with permanent marker.
The sharpening process is to roll the gouge following the parabolic curve while swinging the tool from the 40° line on the table to the centre, repeat on the other wing and finesse the join at the central curve (so basically the same 3 part process recommended for the fingernail jig) you are aiming at perfectly straight wings and of course a 40° bevel.
I then hit a large octagonal piece of horse chestnut mimicking what Stuart had done on the video and I was cutting massive shavings in rounding off, squaring the base, cutting a tenon, and did indeed achieve the outside curve of the bowl in three cuts without any torn grain.
Third picture shows a close up of the inside of the bowl, as you can see not exactly perfect cutting grain, and bark inclusions as well but a cut that I am pretty pleased with for a first attempt.
I have already suggested that Robert Sorby should add this 40° position to future ProEdge development, having used it I am convinced it is a great improvement on a great sharpening system.
I suspect I have now invalidated my guarantee, drilling holes in tools is not normal! but that is what I have done! on the inner range of holes there is space for an extra hole at 40° (third one down on inside track in the photo, I did draw a circle round it with marker pen but 3rd one down is probably easier to spot!)
I suspect that Sorby use an imperial drill on the original machining as it was bigger than 7.5mm and a smidgen smaller than the 8mm drill bit I used. To work out where to drill I simply used my digital angle finder, took a reading at the 35° and 45° existing positions then clamped it up at 40° to mark the new hole position. If you are inspired to copy this idea, don't be tempted to drill through the moving plate, that bit is threaded!!
I then measured 40° from each side of the belt drew a pencil line on the table and coloured in the corners with permanent marker.
The sharpening process is to roll the gouge following the parabolic curve while swinging the tool from the 40° line on the table to the centre, repeat on the other wing and finesse the join at the central curve (so basically the same 3 part process recommended for the fingernail jig) you are aiming at perfectly straight wings and of course a 40° bevel.
I then hit a large octagonal piece of horse chestnut mimicking what Stuart had done on the video and I was cutting massive shavings in rounding off, squaring the base, cutting a tenon, and did indeed achieve the outside curve of the bowl in three cuts without any torn grain.
Third picture shows a close up of the inside of the bowl, as you can see not exactly perfect cutting grain, and bark inclusions as well but a cut that I am pretty pleased with for a first attempt.
I have already suggested that Robert Sorby should add this 40° position to future ProEdge development, having used it I am convinced it is a great improvement on a great sharpening system.