Short of paying about $800 for a pair of custom shafts, the other option was grafting the Mini & Toyota shafts together - a method I've seen in various engine swaps that provide a reliable solution, but I assume as long as the drivetrain is not abused.
I cut the factory shafts and machined them to size in the lathe. The Mini shafts weren't too bad but the Starlet shafts were HARD. Even with carbide inserts on the lathe, I could only cut 0.1mm at a time so 4 hours later, I had two pieces for either side of the car. This pin arrangement kept everything aligned once they were lightly pressed together.
I was planning on getting a pro welder to weld the shafts but after consulting with a workshop, we discussed the process they used and I could probably do it myself if I was confident enough with my welding (that's a yes). To give it the best chance of success, it was suggested to preheat the shafts to at least 250degC to minimise the temperature difference between the area being welded and the rest of the shaft base material, and this would help the entire shaft cool at a similar rate therefore helping to lessen shrinkage stresses that can lead to cracking and distortion. After welding was complete a SLOW cool would be required, NOT quenching.
I tested/confirmed the correct settings on the MIG welder on the leftover shaft pieces and then with my pizza oven cranked to 300DegC
the shafts were preheated and the V groove area filled with welds.
Each shaft was put back the oven and allowed to slowly cool to over 4-5 hours. Once cooled, the welds that sat proud of the shaft surface were then machined off
I then made a custom 3mm thick sleeve to be welded on over the join area and also drilled some holes in the sleeve for plug welds. The reason the sleeve in the photo below is so short is that there is only about 40mm between the inner and outer CV boots, otherwise I'd have made it longer.
I repeated the same preheat, weld, cool-down process for welding the sleeves and used the lathe to clean up the shaft afterward. These sleeves may not be necessary, but it was simply an attempt to provide more strength to the join areas. Once completed, the runout was checked and came in at a very acceptable 0.008in / 0.21mm
After a quick paint job, I gave all the parts (with brand new outer CVs) to a workshop to assemble.
_________________
-Alan
I blame my dad for my love of minis. I think I was conceived in the back seat of one
I also blame my Dad for me being 6' 1" - not really the optimum height for driving a Mini.