Long Shen front mech braze-on being modified to 31.75 to mate up to Reynolds 853 Proteam BX2185 seat tube 31.75 tapered to 28.6 x .8/.5x650. Boss is held on a 1" rod stock turned to 9.5mm o.d. Took half a day to machine the holder and a 3/4x1-1/8" alignment piece but the fit-up is excellent. Now to convince Long Shen to cast a 31.75 front derailleur boss!