The front half is stepped inward to locate with the rear outward stepped half precisely. The center shaft is .5000 dia, precision ground, full hard O-1 tool steel. The ball universal end is machined as an intergal part of the shaft & is therefore exactly concentric. The ball is drawn down to a spring (blue) temper to accept the .001 press fit of the pin. Notice the cavity at the top of the housing where the barrel type out let valve sets. At the bottom of the housing a .1252 dia dowel pin locates both halves precisely. Also visible in this picture is the rotor & rotor mounting method used; two .250 thick hubs with 6 (6-32 SHC screws); one hub threaded & pressed on the center shaft (a coned point set screw is also used to ensure correct positioning); the other hub with clearance holes to locate squarely any rotor used. Rotor thicknes can be .1250 or .1562 & still be centered correctly.
