So I was looking for another calculator to check if I screwed up with Sheldon Brown's and I came across this one. Really easy to use. And fortunately for me it gave the same results.

At any rate if you need one give it a try

https://www.kstoerz.com/freespoke/

This is my first choice spoke calculator. Has worked for me thisfar!

Unfortunately, they don't seem to have in their database the Campagnolo Nuovo Record high flange hubs with the vintage 120 mm OLD rear or the 100 mm front.

These truly C&V hubs plus a pair of Velo Orange PBP rims are sitting out in the garage awaiting use. The wheels I am using are 40 years old with a HUGE number of miles on them (100,000 miles?).

Maybe I should try Sheldon Brown's site.

I would be very surprised if Sheldon Brown's calculator didn't have them. Make sure that you enable the macros so that the automatic stuff works

Edd is also good for vintage wheelbuilds

From Spocalc:

I like the Leonard spoke calculator.

https://leonard.io/edd/

I’ll use the databases in these apps for reference but I’ve learned from many folks on these boards to always use my own measurements. In my experience, it is not uncommon to be 1 or 2 mm off from the app’s database. I’ve also seen database specs that are totally whacked.

OTOH, I have not had a problem ever. I simply round any decimal up, even .1 to the next whole number. Anything less than 1.0mm too long is not a going to be a problem.

Spocalc simply works. TabA / SlotB

As an aside, 90% of the old bikes I purchase or work on have spokes 2mm or more too short, sometimes way short. I’m not recommending it, but just a data point. I will admit I don’t travel in the rare high end classic bike circle.

2mm wrong doesn't make a right

I know, and I strive to get them right too. Often it seems that the whole bike was built with the same spoke length. I’ve seen it often enough that I wondered if it was an acceptable way to do things in the 60s and 70s. To the original question, I like that Leonard’s Spokecalc site although it doesn’t have many of the early Weinmann rims that were so common in the 70s.

The Sheldon and the Leonard calculators work pretty well, but so do the Howard, Raj, Penny, Stuart, Amy and Bernadette calculators.

I've been using the Roger Musson calculator at https://www.wheelpro.co.uk/

I started wheelbuilding using a pirate copy of "Wheel Building" by Roger Musson.
Decided I liked it a lot and paid the money, so now I can use his calculator (which was free when I started).

The bit that convinced me was
1) It agrees with other calculators
2) I've built about 8 wheels and they all worked
3) If you hit the "Log" tab it explains the calculation
eg.