Originally Posted by
FBinNY
The key to hammering a pin out is to ensure that 100% of the energy goes into moving the pin.......That first requires that the crank is supported against a high inertia object (anvil) so it cannot move when struck, and roll with the punch, so to speak. Proper support also ensures that none of the hammer's energy goes to the bearing.
+1 At the risk of being repetitious, I'll also emphasize the absolute need to support the crank arm with something solid if you are using a hammer to 1) absorb the hammer blow, 2) prevent bending the spindle, 3) prevent bending and distorting the frame's bb shell. A length of steel pipe, say 3/4" diameter or so, stood vertically on the floor and solidly shimmed so it fully supports the crank arm with the cotter head centered over the opening is a good way.