Not only is there a difference in shaft size eg: 10mm and 3/8inch but they can have very different head sizes as well.
I use 10mmm bolt that have a 17mm head on them, when prerparing them I have to round the edges off a little just to be able to get the bolt plate over it.
But the old 3/8 bolts, (at least the ones at my local crag Tinbeerwah,SEQ) have about a 14mm or equivalent head size! Very different story. |