Park tool threadless saw guide oversize sg7 2accurately guides a hacksaw to cut aero shaped seat masts and seat posts up to 275 70mm as well as fork steerer tubes and other round tubes from 1 116 to 1 34 27mm to 45mm the sg 72 features two different cutting slots standard and carbon cutting blade widths in a hardened steel body with moulded contact points to protect tubes and frames features the sg 72 cutting guide is a specially shaped guide designed specifically to acc