Hi! Thanks for your inquiry. We puchase high quality stainless steel drill bits. Length 75mm, connection R=1/2 GAS. All diameters from 4mm to 80mm.In addition we would need peripheral wheels, external diameter 100mm, internal hole 22mm, with holes for cooling. Segmented flat for rough grinding and segmented with trapezoidal profile for glass thickness from 4 to 19mm. OK? Best regards Horst Schraml