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.

Bernina 740 Industrie

This machine was found on Gumtree and was in Melbourne but it was the start of December and I was driving down there (it's 1,750 KM from me) for the holidays. The guy kept it for me and had thought I'd driven down just to get the machine and was driving back immediately, bless him!
Can't believe that it was advertised for 3 weeks without any other offers.
It's a 1967 Bernina 740-11 industrie. It had some surface rust from sitting outside, but overall is in excellent condition. Almost identical to the favorit, except for the needle, motor (clutch motor), bobbin winder (external) and knee lift (in the bench). The clutch motor looks almost new and the rest looks in excellent condition.
The first thing I noticed was how fast it is. He plugged it in to test and it went through that test fabric in about a second.

Bernina 740 Industrie

It didn't come with many accessories or any spare bobbins (and they're not common or cheap - got mine from Cyndy). The machine has a full rotary hook (hence the speed), loads the bobbin from the back and uses the industrial (round shank) version of the common domestic needle - 16x231/1738/287WH.
It had a lot of issues. After checking the wiring and cleaning the motor, the machine's timing was seriously out. The needle was timed to hit the bobbin case every time. Not sure why the previous owner didn't just get it fixed but the problem was that the needlebar height, hook timing and feed timing were all massively out of adjustment. I suspect the previous owner, an electrical engineer, had bought it to sell on and doesn't know anything about sewing machines - There were two empty ten packs of needles and a broken one up the spout. It took a while to fix it all but she now sews a perfect stitch. The ultimate test was a tiny stitch with an embroidery stitch.

Nicely balanced at last!

It has a full rotary hook, vertical bobbin with a reversed bobbin case (inserted from the back).
 I'm really happy with this, and it should get well used at my place, especially now we have this plague and the caregivers need us to make them scrubs.