Norris Lockley, who knows much more than I do about many things, wrote, <snip>
Large flange hubs were also extremely popular for the wheels of touring bikes as they permitted the easy use of the 4-cross spoking pattern in which the spoke leaves the flange at almost a perfect tangent. 4-cross spoking provided very strong and resilient wheels as even though the 4-cross spoke would normally be longer and heavier than a 3-cross one..the effect of the larger flange was to reduce the length and therefore, weight of the spoke.<snip>
Norris, you're right about the almost perfect tangent. That means that the line from spoke nipple to spoke hole is almost exactly perpendicular to a line from spoke hole to center of axle. For almost any reasonable flange size.
I just checked my spoke calculator spreadsheet to be sure. There's generally no more than 1 mm. difference in spoke length between a HF and a SF (whoops, large flange v. small flange) for the spoke counts I use. That's about the spoke length difference I use between left and right sides of a 5-speed dished rear wheel. 3x and lower count are different.
I don't build a lot of wheels, and I have a bunch of spokes in house. When it's time to build another, I'll confess to choosing the number of crosses (2x, 3x, or 4x) by what spokes are in hand that will work, unless it is a set that has to be exactly right for a vintage restoration. It works for me.
harvey (more pragmatic than pure) sachs
mcLean VA