Sorby Hollowmaster bits

[Adam Petersen]

Hi,

I have a Sorby Hollowmaster that I am having troubles getting to cut well. I've sharpened and honed the bits on my waterstones, but do I need to turn a burr on them too? The edges feel keen, and I can easily scrape my fingernail with them, but when presented to dried wood blanks they don't cut real well. I've looked around online and read the instructions to them. I sharpened per the instructions. I was just curious if anyone had any thoughts on turning a burr on the bits with my burnisher.

Thanks!

Adam

[Tim Rinehart]

Adam, sometimes when I'm hollowing, I'll forget to readjust the elevation of my tool rest and if it's a little low, it will prevent the tool from cutting kinda like rubbing the heel of a gouge before starting any cutting. If you have a grind on the tips that isn't much less than straight down, that could cause issues also. I think I grind mine about 15Deg.

Edit: I realized your answer wasn't completely answered. You shouldn't have to raise a burr, a sharp edge should be fine. I sharpen mine on the grinder with the top down, leaving a slight burr, but nothing like when you raise a burr on a scraper. If you are doing this on closed forms where you can't see what the tip is doing, try working on an open form, even if just practice, to see what's going on with how the tool is being presented to the piece.

[Wes Ramsey]

I've had good luck doing the same as Tim - I keep the original angle and sharpen it upside down to get a bit of a burr.

[Adam Petersen]

Thanks guys.

[Scott Hackler]

I increased the angle of the bevel on all my hand hollowing tools (probably another 5°) to just prevent rubbing. I also only "sharpen" the bits by using a downward stroke with a 600 grit diamond stone, while rolling it around the edge of the bit trying to mimic the bevel angle at the same time. Usually two of these motions gives me a fresh burr and that cuts well.