Thread: A sharpening jig for Woodcut Bowlsaver knives

G'day
I normally give my bowlsaver knife a touchup with a diamond hone when I go to use it, but there comes a time when it needs a touchup on the grinder .
I find holding such a small surface at a repeatable angle to the grinder difficult and the metal on the tip disappears at an alarming rate if I have take two or three swipes to get an even cut, so I decided to do something about it .
Woodcut suggest that the cutter should be ground with zero rake for softwoods and 5 degrees negative rake for hardwoods .I have no means of measuring such slight variations and in any case I core bowls from rock hard burls to dripping wet camphour laurel so I just used my cutter as it came from Woodcut.
Some time ago , When the $Oz was much more favourable against $NZ than it is now , I purchased a spare large cutter which has been unused.
I started off by turning a disc of about 15mm pine untill it was the exact internal radius of the large cutter .I then cut a small groove with a parting tool, for the edge of the tip to sit in , so when the cutter is sat on a flat surface ,the blade will fit neatly up against the curve .
I already had a platform which I use for grinding scrapers .This is about 7mm above centreline of the grinder .I cut a section out of the disc I had prepared and screwed it on to the platform with one screw .I then took the new, unused knife and marked the surface of the cutter with a marking pen then sat it on the jig and rotated the grinding wheel by hand ,then checked the surface .I then slightly adjusted the jig untill it was evenly touching the cutter tip all over .I did not have to adjust the height .I then put in a second screw to fix it in this position .I screwed an extension piece to the right hand side of the jig to better support the knife and screwed locating stops to the bench to ensure the grinding platform always goes back in the same position .
On checking the old knife in the jig , I found that it had moved considerably from the original setting and reground it .
Hopefully I will now be to get a repeatable grind and lose less meat.
Ted