Started work on mating the Land Rover shaft to the Corsa shaft.
As mentioned this will be pinned, welded and press fitted.
Measuring the torque on the standard Land Rover steering it can be as high as 30Nm, this is worst case with the vehicle stationary, tyres down at around 20psi and a firm grippy surface. If the power steering is working then this max torque figure will be very much less and obviously when driving even lower still.
The plan is to join the two shafts you see below.
The top one is the Corsa shaft that has been removed, you can see some splines on it, this shaft was pressed into the small stubby shaft below and welded together, none of the parts are hardened. I want to fit the longer Land Rover shaft seen below into the small stubby one.
Land Rover shaft has been roughed out, the turned down part will be pressed into the Corsa part.
If I can get an interference fit of 0.02mm the joint should be capable of transmitting over 200Nm of torque. Once assembled this will also be drilled and pinned, a 4mm diameter silver steel pin should give me a safety factor of 4 so I will put in a couple just in case. Finally where the shafts butt up to each other they will be TIG welded together.
The challenge will be getting the two shafts pressed together with a 0.02mm interference fit, plan at the moment is to put one in the oven at 200 c and the other in the freezer then assemble in a hydraulic press, think I will try a dummy run first just to make sure I can do it without undue distortion.