The Faithfull aluminium oxide vitrified grinding wheels are suitable for use on most types of bench grinders and are suitable for normal grinding of ferrous metals. 125mm wheels have a bore size of 19.05mm and are supplied with a 12.7mm reducing bush. 150 and 200mm wheels are supplied with bore reducing bushes and will fit bench grinders with the following shaft sizes: 31.75mm, 25.4mm, 19.05mm, 15.88mm and 12.77mm