Checkers Auto Parts has this universal type of battery terminal shown in the top picture which will fit any size cable. Almost any auto parts store will carry this item. Simply cut off your existing damaged terminal with a hack saw near the end of the terminal. Then strip a portion of the insulation from the cable, clean the cable itself with a sharp blade, then fasten the cable to the new terminal. Make sure this is done with that battery cable disconnected from the battery first. Don't do this with that cable still hooked up to the battery. I believe you said this was your positive side cable. Before you do anything, disconnect your negative cable first. Anytime you do anything with your electrical system, always disconnect your negative battery terminal first. Now, in your case, you will be making repairs to your positive battery cable, so, disconnect your negative terminal first, then disconnect your positive terminal. After your repairs are completed, connect your positive ternimal first, then connect your negative terminal last. Always in that sequence. The reason for this is because, if you hook up your negative cable first, then you hook up your positive cable, and while tightening your positive cable your wrench comes in contact with any part of the cars body, this will create a very large arc, which will cause some type of damage to your new cable or battery pole. I know you mentioned that your bolt keeps spinning. You will have to find a way to remove that bolt safely. What ever you do, do not use heat or anytype of flame near your battery, it could explode. Most batteries contain acid inside which is highly toxic and the fumes could ignite if flames are present. If you have not removed the damaged cable yet, and find it near impossible to get the bolt removed, you could use a dremmel tool with the small grinding wheel which I use shown in the lower picture. I have the 90 degree attachment installed on my Dremmel tool shown in the picture, which you don't need. You can just use the shaft that will accomodate the grinding wheel and attach it directly to your dremmel tool. The grinding disk are approximately 7/8" of an inch in diameter. You could cut the bolt in half at the center of the terminal by using this tool. There is usually a small gap there (between the terminal that compresses the battery pole) where the disk will fit and be able to get at the bolt. Grind half way through the bolt, then spin the bolt, then grind the other half. This will prevent you from grinding too deep into the terminal. You want to stay away from the top of the battery as much as possible. If you decide to do this, be sure to get a towel or rag, and soak it in water, then squeeze out most of the water so it's not dripping wet, and cover the battery completely, preventing any sparks from the tool disk landing anywhere on the battery. Good luck, Tommy.