Glad you got it fixed. I also found that there is no universal spec for speaker posts. I had spades that worked fine on most speakers but wouldn't fit others (Paradigm runs big). I am not talking by a lot though, maybe 1/32- 1/64 too small. Just enough so the spade doesn't slide on.
If you have to do this again next time try using an appropriately sized drill bit that is just slightly larger than the spade. Hold the uncut round end perpendicular to the spades "tongs" and gently tap the rod in with a small hammer till the tongs spread and the drill rod almost bottoms out. This method is a lot faster and neater than filing and it will not damage the plating (if plated). I would not be concerned about cracking a quality spade. If your spade is made from hard brittle brass it should be upgraded anyway.
If you have to do this again next time try using an appropriately sized drill bit that is just slightly larger than the spade. Hold the uncut round end perpendicular to the spades "tongs" and gently tap the rod in with a small hammer till the tongs spread and the drill rod almost bottoms out. This method is a lot faster and neater than filing and it will not damage the plating (if plated). I would not be concerned about cracking a quality spade. If your spade is made from hard brittle brass it should be upgraded anyway.