I've done most of my own work over the years but I stayed away from building wheels. I finally decided to try my hand at it and I'm trying to build a reasonably bullet-proof touring wheelset for a 1984 Univega Specialissima. Right now, I'm doing the front wheel. My components are:
Shimano 105 HB-1050 hubs (NOS).
Flange dia: 38mm
Flange offset: 35mm (both sides)
Velocity Atlas 700c, 36H eyeleted rims (new)
ERD: 605mm
Offset: None
DT Swiss Competition spokes, butted 2.0/1.8/2.0; DT Swiss 14mm chromed brass nipples
Spoke length: 294mm
I'm using 3x lacing.
Here's my problem. The wheel is laced up. I started out using Jobst Brandt's book but I thought I had screwed it up, so I took it apart before I tensioned anything and went to Sheldon Brown's site. I laced it up again and I have the same problem. The spokes seem to be too long. I tried several different calculators and got virtually the same result: between 293 and 294 mm. Following the directions from both sources, I threaded the nipples on a few turns. They seemed really loose, so I tightened them until the spoke threads were just at the bottoms of the nipple sleeves. Still loose. In many cases, the nipple heads still protruded from the inner wall of the rim. Finally, I turned all nipples until the ends of the spokes reached the bottom of the slots in the nipple heads. Some if the spokes have seated but there's no tension and some of the heads still stand proud of their seats. I'm a bit leery of proceeding. What am I doing wrong? I've measured the spokes and the length is correct (at least as far as the online calculators are concerned). When I thread a nipple onto a spare spoke, it bottoms out before the end of the spoke rises above the head of the nipple, so I have very little length to spare for tensioning/truing. Should I just give it up and order shorter spokes or am I missing something?
Note: One of the many sites I checked for specs on the rims gave the diameter as 605 (603). Does this mean the 605 ERD published in about a million places (including Velocity's website) is wrong?
...just out of curiosity, at what point in the lacing process are you making the judgement call that the spokes are too long ?
Have you already made the hub twist, and laced up the third and fourth sets of spokes ? If so, then I have no advice. If not, that would be one answer.
Also, as already mentioned, if you get the number of crosses wrong, this will produce a similar result to what you are describing.