Just use over sized holes on all the inner pieces and 13/32 for the
hole in each outer piece. It is the clamping strength that matters not
how tightly it is held internal.

On Oct 8, 1:41*pm, "Bill" wrote:
In gluing boards together to make a 30" by 7' top, a few months ago, someone
(sorry, I don't recall who) suggested including a threaded steel rod to
guarantee strength. *I just happend to pass by some today, so I came home
with a 72" piece, 3/8" in diameter. *It occured to me that I could face
"alignment challenges" if try to use more than 1 steel rod, especially if I
drill holes that are precisely 3/8". On the other hand, the steel rod (s)
may help with alighnment when gluing.

I expect to use 2 nuts on top of a washer at the end of each threaded rod
and cover them for the sake of appearence.

Bottom line: Do you advise, 1, 2 or 4 threaded (29") steel rods?

Thanks,
Bill

P.S. In case anyone is interested and hasn't seen them, I posted skeletal
design diagrams I made with SketchUp at alt.binaries.pictures.woodworking in
the thread "Second SketchUp".