Spoke Wrench
 

Is there a common spoke nipple size used on bikes? I will be using it mostly on old 10 -12 speeds and dept store MTBs with normal low end wheels nothing exotic. Is Pedro's yellow handled wrench 3.3mm the right thing for this? I have a multi size ring shaped tool but it is confusing me on every spoke. The one marked 14 (guage) on it seems to work on the Fuji/Ukai wheel I used it last.

There are three common spoke nipple sizes used on bikes and Park sells a set of three reasonably priced color-coded wrenches that should cover anything you are likely to see. They are:

Black handled SW-0 (3.23 mm) that fits DT, Wheelsmith and other high quality spokes.
Green handled SW-1 (3.30 mm) that fits Union and a few other European spokes.
Red handled SW-2 (3.45 mm) that fits older Japanese spokes.

Another possibility is Park's SW-10 adjustable spoke wrench that covers all three sizes in one tool.

Round multi sized, the common ones seen most often are not very well made.
and was a PIA to find the 'right' size, again, every time you set it down.

From what I remember even the "right" size wasn't really all that right on most of them. Campy did make a high quality ring spoke wrench but most of the others had pretty wide tolerances.

What I used to do was find the slot that was the best, snuggest fit and paint a spot of red fingernail polish at that point on the wrench. That gave me visual clue which slot was the correct one without all the trial and error each time.