Regularly maintained machines can still give you a nasty surprise.
Before starting my latest project I thoroughly oiled my Singer 15K treadle, taking particular care to oil all the accessible points revealed when the rear inspection plate is moved. I also made sure that I oiled the felt oil reservoirs at the top of the needlebar and presser bar and the ones that are reached through the holes next to the spool pin. These two previous posts show my 15K hand machine, which has exactly the same innards. The mechanism was in a different position, which explains why the photos seem so different.
So I have been quilting happily over the last couple of weeks, and everything seemed fine until last night. Suddenly the machine started labouring, sounding as though it hadn't been used for aeons and I had just brought it home from a second hand shop.
A good half hour was spent checking the machine to find which particular spot needed oiling. It was a real puzzle, because there was still plenty of oil in evidence from the last time. Eventually I realised that the noise was coming from the U-shaped junction on the left in the photo above, where a shaft that goes down the pillar to the base of the machine joins the horizontal rod that is turned by the wheel. In theory the oil reservoir should keep this joint well lubricated.
The right side of the joint was fine. However, to the left, where indicated by the knitting needle, it was bone dry, as if it had completely missed the last oiling. Needless to say, I have slathered the machine in oil, and it is running like a train again.
Why did it dry out so quickly? I'm not sure. Either I have been using the machine more than usual (I didn't think I was); or, the oil reservoir no longer wicks as it should; or, perhaps because of the U-shape and the position of the needle when the machine is not in use, the oil has a tendency to drain away. Who knows? Who cares? The problem is fixed, and I know what to look out for in the future.