A very clever carbide burnisher designed by Isaac Smith of Blackburn Tools, with shallow grooves that turn a burr on both sides of the scraper simultaneously.
The three grooves are at slightly different pitches, so they each turn subtly different burrs. The shallow one is ideal for thin whippy scrapers used for delicate work, the steepest is for coarse burrs on thick scrapers used for heavier work like removing old finishes, the middle one is your everyday choice for anything inbetween.
Hold your Accu-Burr™ carbide burnisher perpendicular to the prepared scraper edge and centered on your chosen groove.
Using a moderate downward pressure and draw it firmly and smoothly along the length of the prepared edge (a drop of oil or wax on the burnisher will make this action even smoother).
This burnishing will raise a barely perceptible burr, but that is the bit that does all the work. You can sometimes freshen up the burr a couple of times with another pass of the burnisher, when its done just file back to a square edge and start again.
Manufacured in the USA by Lakeshore Carbide and marketed by Union Mfg Co, the Accu-Burr™ is fast, effective, and hits the mark every time.