Or “It’s yer brushes, lady”, depending on how thick the carpet is in the shop. If there is one.
But what does it mean? Well, first off we need to know what brushes are. They are bits of carbon on the end of little springs, and here’s a picture of two pairs of brushes from vintage Singer motors. The top pair are more or less new, and the bottom pair are past their best before.
The motor on your vintage Singer has two of those brushes, and their purpose is to conduct electricty from wires which don’t move to a bit of the motor which does, in order that the motor might turn and drive your sewing machine. That particular moving bit of the motor is called the commutator, it’s a kind of rotary switch made of copper segments, and it lives on one end of a shaft at the other end of which is the little pulley with your drive belt on it. Those springs push the carbon against the commutator, which is whizzing round at a fair old rate when you step on the go-faster pedal, so not surprisingly the carbon very slowly wears away.
How it works in practice is that the brush itself and its spring live in a square brass tube with a closed end against which the spring presses, and that fits in the motor like this …
It’s held in place by that curved bit of phosphor bronze, to bottom end of which is soldered that wire with the hairy insulation on it, which as far as we’re concerned here goes to your foot pedal. That’s how your expensive electricity gets from there to the rotating commutator, which is that copper-coloured segmented thingy under the end of the brush.
It’s a bit of a pig to photograph clearly, so here’s a slightly different view at no extra charge …
So now you know far more about Singer motor brushes than most people do, and if you run a vintage Singer electric, sooner or later this new-found knowledge will come in handy. How so? Well, when one day you notice that your machine is making a funny metallic noise and your investigations confirm that it’s coming from the motor, you won’t need me to tell you that it’s yer brushes. They have worn out, and if you keep trying to run your machine like that you will do it No Good At All.
New brushes are readily available online at £3.50 or so a pair including p ‘n’ p, and it’s not a big job to change them. So, you ask, is it a DIY job then? Well, if you’re possessed of an ordinary screwdriver, common sense, patience and an affinity for things like this, I can’t see any reason why not. If you look at the back end of the motor, you’ll see at the top and at the bottom a screw head hiding down a hole. Undo the top one, take it out and you’ll see that a section of the casing lifts off, revealing exactly the view in those pictures above.
What you need to do is ease that square brass holder out, taking care not to let the brush and spring drop into the innards of the motor. Having successfully extracted the brass thingy and removed the spring and dead bush, take a Q-tip, soak it in lighter fuel, meths, vodka or even WD-40, stuff it up the open end, pull it out and marvel at the amount of carbon dust that was in there. Repeat as necessary, but it doesn’t have to be clinically clean. Then insert your nice shiny new brush and spring into the brass thingy, and reassemble right way round. Which, though not difficult, is admittedly easier said than done the first time you try.
But fear not, because if you screw up, you have these pictures to refer to, and you also have a real life example of the correct assembly.
Oh yes you do.
You haven’t touched the bottom one yet and that’s identical …