david, 3/8-16 is a standard coarse thread, and it will generally measure around .360 for the major diameter of the bolt, (unless its a class "A" thread which will measure alot closer then that),the tap drill for a utility class thread in 3/8 - 16 is 5/16 which is pretty darn close to what you have, and there is always working clearances built into fasteners so they spin on easy and and so that the coating they put on them doesnt make it too tight,
the 12 MM ones you were looking at are pretty large for what you want but it could certainly be done, they would measure nearly .470 for the major diameter,
for future reference, american standard threads are measured in Threads per inch as you know, but metric is the distance between the points of 2 threads,
i hope this helps you out,
kevin
the 12 MM ones you were looking at are pretty large for what you want but it could certainly be done, they would measure nearly .470 for the major diameter,
for future reference, american standard threads are measured in Threads per inch as you know, but metric is the distance between the points of 2 threads,
i hope this helps you out,
kevin
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