It's really the duty of a good dealer to make sure your spade lugs are sized appropriately...yet few will bother, as it takes time and sometimes work on the customer's part to check their post dimensions. I'll put my customers through the check, but they don't end up with the problems you are having now. On the used market, it's sort of 'buyer beware'.
If they are a light enough gauge or soft enough metal, you can gently bend the prongs outward enough to make them wide enough to slip on your posts. Keep the prongs flat so they don't buckle. Heavier duty spades might have enough metal on them to be filed open a little bit...just 1/32" on each side should do it.
If you change your spades. I wouldn't use the vise grip method...better to use a real crimper designed for the job. Then you also have the issue of shrink tubing, if you want them to look neat. Many people find their first termination job alot trickier to do well then it might appear, so before you hack the old ones off, think it over.
There are some pretty good adaptors sold by AudioQuest & Apature...it's the same part, and sold perhaps under other names as well. It is a banana that bolts on to 1/4" posts. Could be a good way to go.
Jeff Delman
Value Audio
