The Honing Guide is used in conjunction with either an oil, water or diamond sharpening stone to ensure the perfect cutting angle when restoring a cutting edge to straight edged chisels, bevel edged chisels and plane irons from 3mm to 67mm wide.
Use the inner jaws for chisels, a blade projection of 30mm will give a 30 degree angle and 40mm will result in a 25 degree angle.
Use the outer jaws for plane irons with a projection of 38mm for a 30 degree angle or 50mm for a 25 degree angle.