PART NO. THREAD DIMENSIONS E F A B L S1 6M-12 M12X1.5 M12X1.5 15 34 53 17 6M-14 M14X1.5 M14X1.5 15 34 53 19 6M-16 M16X1.5 M16X1.5 14 36 57 22 6M-18 M18X1.5 M18X1.5 16 36 59 24 6M-20 M20X1.5 M20X1.5 16 36 62 27 6M-22 M22X1.5 M22X1.5 17 38 65 30 6M-24 M24X1.5 M24X1.5 17 59 67 32 Note :In case if you are interested to order the adapter in complete set with lock nut ,it is necessary to insert suffix "LN" after our part no.,for example 6M-16LN