Suggestions:

I have you contacted Black and Decker directly?

I have you gone down to the B&D Dealer and look at the power cords in the models on display? Any similar to yours that you could order the same part number.

Have you gone down to the local tool repair man? It is possible that he has a box of cables for different brands that people have given him when they find the cost of repair of their tool is nearly as much as a new unit.

Have you checked places like ebay, or your local equivalent?

If all else fails, you could open the case and hard wiring a new male pigtail?

That was a proprietary locking cable from Black&Decker back in the 70's and 80's. Many years ago, I was able to order a 6-ft replacement cable for my drill from my local tool repair shop. The female end looks exactly like the extension cord in your photo. Perhaps that cable is still available from B&D?

Thanks for the info wolley, that's kinda what I was expecting, for it to be a long-abandoned proprietary cable. B&D seemed to have no recollection of this cable connector when I tried contacting them.

It's far too much trouble to continue looking when I can just modify the tool. I was really just hoping to maybe get a name for the cable type like "oh yeh, you need a Whatsitjack 5000" and then I could search it up and find some online store that would have like one left in stock. :P