Sheldon created a great resource, but you should remember he was mainly dealing with Americans new to our type of bike, their native crankset is the 2 piece. So he was totally correct, but if you can't support the crank, support the bottom bracket, so that the force of the hammer is not lost in the frame and wheels. I have never seen bottom bracket bearings, cups or axles damaged by careless hammering, only by water which can cause the balls to split. It is better to press the cotters in, or out, if possible, but the whole essence of the bicycle before about 1980 was it's simplicity.
I have responded to a US request on "oldroads" for information on adjusting a raleigh rod brake!