Hot Rods I got the shaft.

Use the car as a checking fixture before welding!

After pressing the weld yoke in, but before welding, bolt the shaft in the car and spin it by hand to check run-out. If the tube is out more than .005" about an inch from the weld area, a few well placed whacks with a hammer/drift on the weld yoke near the parting line on the high side should fix the problem.

After removing the trued-up shaft from the car, I typically tack weld in three evenly spaced places around the tube first to keep things from moving. After that I start making final welds by starting between the tacks and then welding to the tacks.

I've built hundreds of shafts from scratch using this method, except I use my large lathe as a checking fixture instead of the car. The first few were taken to an actual driveline shop for balancing, but they so close that I eventually eliminated that step to save my customers money. Build all my own personal shafts the exact same way.

Grant

 

Done all mine at home and no issues. My last one happened to be from a donor 3rd Gen Camaro, so just needed adapter joints to mount the Ford flange at the rear. But the one in my Austin I did 13 years ago, and has 20,000 smooth miles on it now.
If I ever had one that vibrated I'd be glad to take it to the local driveline shop and have it checked. So far I haven't had to.

 

About how i do it.
I just run a line down the shaft when it's in the lathe with a felt pin in the tool post and mark the end with a punch so after it's cut i just line it the mark with the existing line . Then it's indexed the same as when I started.

The bevel also helps keep the weld were you want it.
In the 80's i used a stick welder and 7018 rod as I recall .
My grandfather had a variable speed drill with home made adapter made from some hose and pipe fittings set up to spin them while you welded . He used it on welding up pipe a lot .

A buddy did one with a 4.5" grinder with a cut off wheel to cut the weld and a pipe cutter for black pipe to cut it square and a AC Forney welder . It's been in his BBC 67 Camaro for 43 years ran low 12's with slicks .

I don't have acess to the big lathe any more .

 

It's kind of like mounting tires on wheels....every now and then you get lucky and don't have to put any weights on. If it doesn't vibrate why worry about it? Why balance something that runs smoothly?