Burnishing is the process of smoothing, polishing and slightly compressing the steel's surface by the forceful application of a highly-polished super-hard smooth surface, usually another piece of steel. No sharp edges on the burnisher, no metal removal from the surface being burnished. A perfect example, albeit in wood rather than steel, would be the old GI's trick of using a toothbrush handle to burnish his rifle's wooden stock.
Scraping OTOH is the process of actually removing a miniscule amount of steel in order to achieve more-even contact or to provide for better lubrication of sliding parts. It's usually done as Kutter described, by the operator bracing the long handle over his shoulder and applying pressure on the hardened-&-sharpened front edge as he draws it toward himself across the surface to be scraped. The tool's angle and the amount of pressure determine the amount of steel removed, anywhere from a few thousandths down to a ten-thousandth or less. The tool's operating end is flat, with a VERY slightly rounded front having a sharp right-angle termination; this right-angle is the edge that does the scraping.
Scraping was a common way of decorating the bolt bodies of prewar sporters, especially the higher-grade ones. A series of parallel lines are scraped at about a 45-degree angle around the bolt body, both ways, with a space of 1/4"-3/8" between them. This provides an attractive surface finish somewhat similar to engine-turning/jeweling.
Regards, Joe
