david weaver
roll the burr about 20 degrees over the bevel angle on the scraper, same as any other scraper, but more deliberate on an outside curve.

If working curves similar to the scraper radius, the burr should last about as long as a straight edge scraper, but if the radius of the work is much wider than the scraper, a point of contact is doing most of the work and the burr will be worn or pushed off by the wood faster.

Medium or fine india is what I use to touch up the radius parts and then just polish the edge if you need finer. Fine stone on the face. I can't remember doing too much filing to the two curved scrapers that I use on a regular basis. Better to just stay ahead of huge amounts of wear occurring at the edge with frequent touch ups.

You can use fully hardened steel with no burr, too, but my experience with that and curves is that it's no time savings and spring steel is fast to wear on a medium or fine india stone, hardened is more like sharpening chisels and gouges.