Spinning shafts NEED to be balanced
...& usually with a bit more precision than us DIY'ers have the equipment/ability to do.
Unbalanced or kinda balances axles won't last very long
...& when they do "let go", the collateral damage can be devastating
A quick Google search of: (drive shaft fabrication in southern california) (IIRC your in so, Ca)
Such as, Drivelines Incoporated - A Custom Driveshaft Shop
"Welcome to Drivelines Incorporated
At Drivelines you can expect to find a crew that truly appreciates your business and understands that your job, and your job alone, is the most important.
Drivelines Inc. is an experienced driveshaft shop that keeps full attention on building driveshafts; this is all we do. Utilizing our top-of-the-line balancers, lathe, and workstations, our focus is on building you the highest quality custom, or rebuilt, driveline available. At Drivelines Inc. our capabilities range from BMW's to 18 Wheelers, Off Road Vehicles including high end Trophy Trucks to Custom Built Hot Rods, and everything in between."
...or maybe these guys (in Escondito, Ca)
The Differential and Axle Shop - Escondido, San Diego
Just some "food for thought"