I'm only a hobbyist with a Warco Minor mill with an MT3 spindle so I don't know which 40 taper they are; could be 40 INT, BT40, SK40 or ISO40, I'm afraid I don't know which., had them in one of those 'big boy' taper tooling collet racks next to a Bridgeport, so I'm guessing they were still in use.
eBay