Wheelbuilding / Wheel Building / Wheel build help

Cheers.

I measured the ERD using some spokes with 12 mm nipples in opposite holes. First I measured nipple end to end and added 24 mm. Then I used two spokes cut to 200 mm with 12 mm nipples and measured the gap between the spokes and added 400 mm.

Both measurements were within 1 mm and I repeated around the rim.

Am I doing something wrong to get 605 mm? This leads to spokes 2.5 mm longer and which I'm concerned could lead to problems in the build if my measurement is somehow wrong.

To avoid the nipple bottoming the thread, you measure the distance nipple to nipple and only add 2 times 10 mm instead of the 12 of the nipple.... this way you should get 601