used in conjunction with a hollow centre to provide the guide and drive necessary for a 5/16" diameter shell auger. The work should be partly bored using the drive centre with the point outwards and the hollow ring centre in the tail stock. The work is then reversed using the drive centre with the 'pilot' to engage in the mouth of the hole and the boring completed. 1" diameter 4 prong head relieved behind flutes to prevent binding. Supplied complete with interchangeable point, pilot and hex key.