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From the upright to the steering arm, there will be bolted connections to attach the two together rigidly. The tie rods will have rod-ends (spherical bearings) or clevises as the connection point depending on what is needed, same with the center link. The centrelink will be connected to the rack using either a rod end (and bolted) or using a set screw and jam nuts. Past the firewall, there will be a female spline rod to connect with the male spline end of the rack. Connected to the female spline will be a male spline rod, connected to a u-joint (to allow for tilt adjustability of the steering wheel) along with a tilting mechanism similar to the one shown below. Lastly, there will be a male spline connecting steering wheel to the u-joint with a telescoping mechanism (will probably require a female spline with a slide fit and pins for adjustability). The column will be held up using a mounting jig with a collar and L bar with a shear pin (to allow for collapse).
Fixture
For the steering shaft, a two-piece collar should be used to hold together the majority of the shafts due to their superior holding power to set screws (distributed forces vs point forces). As well, the shaft material will not affect the holding power of collars whereas set screws should be harder than the shaft material so when it is properly tightened, the set screw should actually indent the shaft (Source).