[email protected] (Lewis Campbell) wrote in message
news:<e68f9
[email protected]>...
> I have a small piece of tube, which is a slip fit on the 1/8" rod and it seats on the place where
> the nipple will be. The rod slides through till it is flush with where the nipple seats on the
> opposite side of the rim. I then, carefully, withdraw the welding rod, so as to be sure my little
> piece of tubing does not move and measure the exposed length of welding rod.
>
There's a tool that was distributed with the Wheelsmith spoke calculator that did exactly this.
In reality, the *exact* measurement need not be that precise... unless the spokes come out too
short.

It's OK if the spokes come all the way through the nipple and project out the backside-
this indicates that the threads have full engagement. If the spoke projects too far, though, you'll
bottom the nipple threads or have to file off the end of the spoke. Neither alternative is fun.
An alternative is to see if any of the spokke calculator databases at
http://www.sheldonbrown.com/wheelbuild.html#length lists the rim you're using. If all else fails,
ask the list.
Jeff