A sharp concave card scraper will reproduce the negative profile to itself easily and crisply, making the clean up and smoothing of spindles, beads, etc. much easier.

Here's how I sharpen mine

Step 1: Watch the Short Video First

Watch the video, then read through the more detailed steps. This should help you understand the process more easily.

Step 2: Make a Sharpening Profile

Use the concave card scraper to produce a short length of profile.

Make the profile slightly smaller than the curve of the scraper. You'll see why later.

Clearly, this is best done when it is sharp, so try to remember this when you buy new profiled scrapers. Angle the scraper to make the profile slightly smaller.

If the scraper is already dull, then you may find it difficult, and using a rasp and flat file may speed the process up.

Step 3: For Damaged or Badly Dulled Scrapers, File First

If your concave card scraper is nicked or very dull, then use a half-round or round file to prepare the edge. You want the 'thickness' of the scraper to be at ninety degrees to the faces, so keep the file at ninety degrees too.

Step 4: Smooth the Edge

Wrap some fine sandpaper over the profile you previously prepared, and use this to smooth the edge of the scraper curve. The thickness of the sandpaper is why we make the profile slightly smaller.

Remember to keep the profile and scraper face at ninety degrees to one another.