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