scrapers and negative rake scrapers

Hi Phoneman

I personally am not a great fan of scrapers, but they do have a place especially round nose for finessing the internal curve on a bowl. Traditionally this would entail a slightly above center line toolrest and a slight 'trail' of the square topped scraper by raising the handle. This works, but can easily rip out end grain, and get the angle wrong and a catch is on it's way.

The basic science of the negative rake is a very small bevel on the top of the tool lowering the cutting edge, this allows the toolrest to be on the center line, the handle to run parallel to the lathe and still be cutting in a trail cut below the center line. Which I personally think fits the muscle memory better so produces a smoother movement hence less grabby cuts and less risk of a catch.

I do feel than a traditional grind on around nose scraper is possibly better when using it in a shear scrape method, though that could just be the way I was taught!

For me scraping is a bad thing, only to be used where better cuts are not working for you, so some of my scrapers have not been sharpened in years (well months up to a year probably) I strongly suspect that in 12 months time I will only have negative rake with something like a 5degree top bevel.

Not really an answer, I think the bottom line is someone has improved the standard scraper grind by making it fit with users muscle memory better and maybe the top bevel however small starts the curl of the shaving keeping the catch risk minimized.

Pete