If you know someone who works in a machine shop or has access to a tool grinder (not a woodshop grinding wheel, a real tool grinder) I think the angle on the business end is 15 degrees. I made a sharpening block out of aluminum stock and just set the grinding table to 15 deg. Mounted the blade to the block so I had a nice flat surface to set on the table and grind away only enough to get a good edge. Mine works slick and sharpened my blade good as new.