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Making a Negative Rake Scraper...
Step 1 - mark out the shape
Step 1 - mark out the shape
Step 2 - Grind the edges down to the marks with a 40 degree(ish) bevel
Step 3 - Ensure each side is equal
Step 4 - Mark out and grind back from the edge to create top "bevels" with an approx 90 degree angle between the two "bevels"
Step 5 - Polish all surfaces with a mop and paste
Step 6 - Re-grind the tool upside down to draw the burr off the cutting edge at the intersection of the two faces. The top bevel is not -re-ground. The top "bevel" should be highly polished.
Step 7- Enjoy discovering that your "scraper" actually *cuts*.
Step 8: Regrind often...here a conventional round-nosed scraper is ground upside down...the way they should always have been ground...to draw the burr off the cutting edge. Note the low position of the rest to allow the CBN wheel to safely grind at the correct angle
Step 9 - The burr can be improved by honing. The hone is pushed upwards to ensure the burr stands upright off the cutting edge
Step 10 - Remember that the "bevels" on a scraper are not for "rubbing"; only the burr edge contacts the wood and cuts the fibres. Conventional scrapers are used "trailing" - handle higher than cutting edge. Neg Rake scrapers can be used horizontally or trailing.
Step11 - Make a GIF!
