Another Negative Rake Scraper question

[Peter Blair]

I'm kind of hoping that Robo chips in here. Lately I have been turning lots of Silver Maple hollow forms and like many other turners I use 3/16 square cutters from the metal industry. Sometimes, especially when I am near the outside of the form at the bottom the cutter can be a little aggressive and grabby. Has anyone tried a negative rake on this type of scraper?

[Don Frank]

Wow, that's an excellent question. I look forward to people chiming in on this one.

[Reed Gray]

That center nib is a royal pain.... If you free hand, you raise and lower the handle and cutter till you hit the sweet spot. I think Dave Ellsworth shows this one. Best to practice on an open form. Some what different with a captured system. The problem with a straight scrape, as soon as the cutter touches the wood, it is on center with no cutting pressure, but under pressure, it drops below center. You don't want scrapers below center on the inside of a form. A more pointed cutting tip will be more grabby than a broader/wider tip, but that is more surface to get stuck in the wood at once as well. I prefer a shear scrape, with a tear drop type cutter at 60 to 70 degrees. It doesn't dig in, so you can be close to center height and still cut the dead center. A negative rake scraper would be better, but still difficult to keep it at dead center under load.

robo hippy

[Peter Blair]

Thanks Robo. I am with you on the 'nib' but for a lot of my forms I really don't care what the inside looks like. With my hollowing rig I can sometimes turn the cutter a little to move the cutter slightly up or down. On my next hollow form I'm gonna re-grind a cutter and see what happens. I do start all my hollow forms by drilling with a round end drill bit and if I'm careful I just have to scrape down to the round indentation that it leaves and walla! No nib!