Seems as though every time I need a three-pronged plug all of mine have sprouted legs and ran off. So, the other day I picked up a few more at the store. None of them seem to fit my cords. The blades will not go in all the way. Are there different sizes of three-pronged plugs and I happened to grab the wrong sizes?
I got tired of this as converted power tool plugs to 20 amp design. Spare plugs stayed in drawers and universal sockets and receptacles made for hassle free connections even with factory 15 amp molded plugs.
What cords are you trying to fit them in? Maybe trying to fit new plugs into old, old outlets? They do seem to have changed the prongs a bit more, and made one prong even wider than it used to be.