UNF ¼” 28G versus M 6
b.safe Fittings come with the most common HPLC thread UNF ¼” 28 G without exception. In addition, fittings and distributors with the very similar thread M 6 exist. These threads can only be distinguished by exact determination of their outer diameter or by using a test mandrel (it is possible to screw in a tube end fitting in the counterpart of the other thread for at least 2-3 rotations). The UNF ¼” thread has an outer diameter of 6.35 mm, the M 6 thread has exactly 6 mm (work tolerances are possible). We recommend to use only the UNF ¼” 28G thread to avoid confusion and double inventory.