This trimming tool is made from steel, oil hardened and tempered. It is rust proof and durable for professional potters. This kind of trimming tool is suitable to trim thin and tight foot ring. Because to trim a thin and tight foot ring, clay should be harder than normal, so we need to keep the blade as sharp as possible. This tool is much easier to be sharpened than commercial loop tools.
To sharpen the blade, use a fine file or a piece of sandstone, hold the trimming tool firmly and about 30 degree, and file the blade horizontally. Do not change the filing angle or holding angle during filing or the blade will not be straight. If you file too much, the tip of blade may become bend to other side. Constantly check both side of the blade with finger tip to make sure it is straight. If it bends to other side, file the back side slightly to make it straight. Do not use high speed motor driven grinder to sharpen this tool as high speed grinder is hard to control and may damage the blade.