I was wondering what the bore size is off the 60C01 clutch gear as I was unable to find it anywhere. Also, what is the pitch of such gear?
Outer (hub): 6.8 mm/.268 in./ 17/64 in.
Inner (shaft): 4.9 mm/ .193 in./ 25/128 in.
Teeth (key): 3.32 mm/ .1305 in./ 17/128 in.
-These are close/approximate, not exact due to the tolerances and/or wear. I measured 4 different gears with a digital caliper and the measurements were all within .10 mm of the listed measurements. The measurements even varied slightly within a single gear depending on side and orientation.
Also, I think you can find the answer to your second question about pitch here: "What is the "Module" of a LEGO gear?"
Had to buy one to check the specs. The Bore size is just under 4 mm (~3.5 mm) in diameter. Without the teeth of the clutch it is just under 5 mm.