Pin size formula for shaft diameter size.

Does anyone know of a formula for correctly choosing the diameter of a cross hole in a shaft to hold lets say a gear or bushing. Lets assume I have a 1" diameter shaft and I would like to put a sprocket on the shaft and use a cross pin (Roll, Straight or Taper) to hold it perfectly stationary. I have been through my Machinist's Bible and can find nothing. I would assume 25 to 30% of shaft diameter would be normal but was just assuming there must be standard table or formula out there somewhere to act as a guide.

Thanks for any help

I didn't find anything on pin size relative to shaft dia. either. Key/keway sizes are ~4:1 . Because a key generally has more shear length, you may want to be a little strong on the pin dia. If there is high force (torque) on the joint maybe more than 1 pin if there is enough length in the joint.

Dick Z