Some time ago, we bought in a 201 for parts and as usual, one of the first things I did with it was to cut the motor plug off the lead. I was about to chuck it in the appropriate spares bin when I noticed that it had been modified …
See that black lump between the two screw heads, and the square thing sticking out above it in the picture?
Well, once I’d removed the two screws and pulled the queerthing up so it photographed clearly, that’s what it looked like!
That’s it from the other side, and yes, it is indeed on the end of a couple of earth wires.
So, somebody has first of all laboriously made that little widget from steel strip. They’ve then opened up the cable entry hole in the Bakelite plug body so it will take two three-core cables instead of the usual two twin-core ones. Having stripped all six wires at the right length for four of them to connect to the three contacts inside the plug body, they’ve then pushed the two earth wires back outside and soldered them to the widget.
After that, all they had to do was find a couple of skinny bolts longer than the original ones with which to fasten the two halves of the plug body together (and that in itself is no mean feat), then put a dab of black paint on the solder to make it all look prettier. Et voilà – an earthed machine plug.
But what, you ask, does it earth to? Well, given that the socket on the machine into which the plug plugs is made of Bakelite, the answer is the that it earths to the only thing it can do – the screw which holds the socket onto the motor mounting bracket!
Comme ça …
That’s the best snap I could manage, but hopefully you’ll see that as the plug in the foreground is pushed into the socket in the background, the tag on the widget slides under and against the head of that fixing screw.
Now, if only it had occurred to me, I could have put the meter across that little lot and seen just how good that earth actually was in view of the number and nature of the contacting surfaces between the earth pin of the 13amp plug on the end of the mains lead and the body of the 201 itself. But it didn’t. Occur to me, that is. So I didn’t. Meter it.
Presumably our hero connected both earth wires because the one that didn’t go to the mains plug went to a metal-bodied foot controller rather than the usual vintage Singer Bakelite one, but who knows.
Whatever, as far as I can see, this is the only way you can earth (or more accurately “earth”) a classic vintage Singer electric and retain the original motor plug and socket. Quite why anybody would want to embark on this task in the first place is way beyond my understanding, but if I wore a hat, I’d certainly take it off to whoever had the patience and the determination to complete it.