the fitter at work showed me a trick where u turn the speed way down and put the die on the end of the bit your tapping
then u use the thingy that holds the drill bits so the die has keeps a bit of pressure behind it and then the die feeds itself on!!
not sure if it will work too well on big threads though
could u have run a drill through the whole axle and then used threaded bar or long bolt (say m10?) down the guts of it?
the bolt