Of all the techniques related to woodworking, this sharpening a card scraper tends to generate the most interest. This is my method:
- Remove the old burr if necessary by rubbing the face of the scraper on a stone. I use my diamond stone as not to scar my water stones.
- Clamp the scraper in a vise with the edge you are working on exposed by about 3/4-1″ (enough room for your knuckles, but not so much that the scraper flexes too much) and mill the edge square by holding a mill file parallel to the edge and taking passes until the edge is flat. If you get the right angle, you can tell that the edge is straight by how it reflects light. Be careful not to create a rounded edge.
- Refine the edge with a water stone. I usually go up to 1200x, but you can go as fine as you like. At this point, I will have a burr on the edge of the blade which will actually turn up shavings. However, the burr is not nearly as durable as a hook, so I proceed.
- Start to roll the hook by taking 2-3 passes with the burnisher square to the edge. Use steady, controlled pressure. If you have any fear of slipping and hurting yourself, you are using too much force! At this point, the scraper is ready for very fine scraping. For a more aggressive cut…
- Roll over the hook by taking another 2-3 passes with the burnisher tilted slightly, using the same force as before. A five-degree angle is great for fine work, fifteen degrees is very aggressive and takes work to push! I usually aim for about five degrees.