buying nuts
but,wait a minute...buying nuts is no that easy. and as there are 2 ways (metric and standard) and how are displayed, is even more fun.
the way to measure the bolt where the nut has to be attached is by measuring the diameter-the round portion where the nut fits.
and in this case is 6mm. but the outside dimension (the hexagon, where the wrench fits to bolt or unbolt the nut) is 10mm (or very close to 3/8").
and for 8mm bolts diameter, the nut is 1/2" (which is not so close to 13mm). and the pitch is another factor.
and the way the labels on the shelves show the size are even more confusing. some show it on metric, others on standard.
so if possible bring the screw where the nut fits, to test the nuts and then buy.
anyway, that is the long story.