Just grabbed one. Overall length 83 mm. Max OD, wheel end, 30.8mm. This section is 20mm long. Reduces to 25mm for 40mm to suit ID of chainwheel ball race, with a couple of flats to locate in suspension lug. Then reduced diameter and threaded for remainder of length,
My records show sleeve nut 67 6074 is threaded CEI 7/8" X 20 TPI
Measured with the cheapest Chinese plastic caliper. As usual, do your own research as to accuracy of offered information.
Internally, machined to match wheel spindle, which on Plunger bikes extends the whole width of the wheel/hub assembly. Counterbored at the wheel end to a depth of 17mm. ID here matches major diameter on wheel spindle, 22.3mm. ID then reduces to the threaded end, reduced spindle OD given as 9/16". Spindle nut 67 6073 is 9/16" X 20 CEI
Swarfy.