this is how i built my balanced 1/4 wall driveshafts for less than $100... i started w/ a piece of 3 1/2" sch40 pipe... which measures roughly 3.5" id... i have just slipped this over the existing tube and welded it up before, but the problem is the thin wall stuff is still the weak link, it wont bend, but it will tear the thin wall loose from the weld and besides it doesnt fit tight, so no way to measure runout... i took my 3.5" pipe to a machine shop that welded up a "flange" on the inside to build up the ID.. they machined it down match the OD of my yokes, then it could be slipped together w/ a press fit and spun on a lathe to measure runout... i did the disassembly, machine shop charged me $40 and the driveshaft shop charged me $50...
unmodified 3.5" sch40...
weld yoke inside of unmodified yoke for comparison...
modified vs. unmodified...
inside shot after machining...
weld yoke comparison to modified pipe...
unmodified 3.5" sch40...
weld yoke inside of unmodified yoke for comparison...
modified vs. unmodified...
inside shot after machining...
weld yoke comparison to modified pipe...
