I would like to point out that there is the distinct possibility that these allen type binders on domestically built frames can be fractional sizes.My 77 Eisentraut is one of them ,so in addition to the usual allen type wrenches in my pocket I carry a 7/32 (while my Hurlow uses 3/16) so what appears to be 6 or 8mm may actually be fractional.
BOB FREITAS
still smokey in MILL VALLEY, CA USA