That butt hook key you refer to is actually called a "gib key". The best method I have found to remove one is with the use of a slide hammer with a vice grip attachment. n1. Replace the adjusting screw of a set of vice grips with the slide hammer adapter. n2. Clamp the vice grips onto the sides of the gib key head securely. n3. Using either a stick welder (7018AC rod seems to work best) or a wire feed welder...weld the jaws of the vice grip to the head of the key securely. Take you time and do a good job, this is the most important part of the operation!! n4. After letting the parts cool for a few minutes thread the slide hammer onto the adapter_vice grips. n5. Apply pulling pressure in a straight line with the key and start hammering with the sliding weight. You don't have to use a great deal of force...start gently and build up until the key pops free. The gib key is tapered and once is starts to move will come out quickly so be careful you don't injure yourself if the key pops out suddenly. The heat of the welding seems to expand the key slightly and as the key cools it shrinks back from the hub and shaft making it easier to remove. The vice grips will ruined (I usually pick up a few old ones at farm sales just for this purpose),and usually the key will be too. But that is a small price to pay compared to having to break the pulley and replace it or spending hours drilling the key out. Good luck! Doc
