I've never checked but I assume that they are all a standard size on the threads.
I second the motion for an easy-out. As it comes out tho (before the last thread disengages) wipe it down to remove any metal shavings. You shouldn't have any problems. Good luck.
My bad - they come in SAE & metric - Look here:
http://www.toolprice.com/category/as...reasefittings/