Elna Supermatic

This machine is from the hoard I'm supposed to fix and sell (I'm doing the responsible thing and not selling during the lockdown). There are four Elnas from around that time and three are like this one.

I've sort of given away the ending there. It didn't look anywhere near that good before I did my thing.
After the cleaning and oiling, it was making this thumping noise. It took about twenty minutes to realise that this is an Elna and therefore has a drive rubber on the motor (see the post from a few years ago on the Lotus).
I removed the hand wheel and sure enough there was a rubber wheel. This one was longer than the Lotus one but very similar.
I had a couple of 50c rubber bumpers left so drilled one with a hole much smaller than the motor shaft. Removing the existing rubber was not easy. You have to drive a pin out while holding the motor still. I jammed a very large screwdriver against the rubber to give it a bit of resistance.

Drive rubbers in foreground. Original is black

The replacement must have a small hole because there is only the pressure of the shaft stopping it from spinning, so to make this work, the rubber needs to take a lot of effort to push onto the motor shaft and you should also minimise the effort needed to turn the machine over.
If you find that this doesn't work, get something higher, so it matches the original and that you can make a very small hole for the pin to go back.

One rubber bumper in place

It works beautifully for me. The way to avoid the problem is to use your machine every now and then.
Oh and here's the 1962 manual I scanned and made into a PDF. It's made to be printed double-sided A4. Original size was approximately US Legal, so if you scale it up it'll be about the same as the original.