Sharpening Curved Scrapers

If you follow this blog at all then you know that I recently built a violin.  Violin making is a scraper intensive task — mostly using curved scrapers.  The scrapers have to be sharpened quite well to function effectively on the soft spruce of the top. When working on furniture I am seldom tempted to scrape softwoods, but it is the best way to go when smoothing the compound curves of the top and graduating its thickness to the tenth of a millimeter. This challenge required upping my scraper sharpening game a bit, so  I put on my thinking cap and came up with the solution pictured here, which tells almost the entire story.

Nevertheless, I’ll add a few words to clarify. The small block of 3/4″  plywood has squared edges. It is captured in my tail-vise along with a fine grit diamond sharpening plate.  The wooden block on top of the curved scraper is attached to the scraper with very thin double sticky tape, creating a handle to maneuver the scraper easily. It is now a simple matter to form a nice sharp, square edge on the curved edge of the scraper. I have some ceramic stones that I used next to polish the edge further.  I finished off the edge by rubbing some white polishing compound onto a square of MDF, clamping it up like the sharpening stones and buffing the edge of the scraper to a high shine. Before removing the “handle” polish the face of the scraper on your finest stones (I use a King 8000 grit water stone). To draw the burr I did most of the work with the burnisher flat on the surface, followed by a very light burnishing on the edge itself to raise a slight burr. This worked very effectively!

By the way, a few weeks ago I was visited by Nancy Malott who came from Kansas to learn plane making.  She made a very nice smoother patterned after one of my Dad’s planes.

In case you are wondering, the tooth brush is used to clear swarf  (man, I love that word) from the face of the stone.

Until next time!
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