One of the reasons that my last bought vintage sewing machines are Elna Supermatic is that it can sew pattern stitches. For doing this you need to have cams. The cams they called Elna disks.
I think that when they buy an Elna Supermatic sewing machine they could choose between 6 or 7 different pstterns/Elna disks, but in the years after with new models of the Elna sewing machine they develped many more. The new Elna disks do match the older Elna Supermatic.
Now I have three sets of Elna disks: two from the sewing machines
The third set of Elna disk is from a newer special set of cams. I have bought it at eBay.
In the special set all the cams are double cams, while in the sets from r´the Elna supermatic sewing machines are both single cams and double cams.
I do not know yet how the cams – the Elna disks – are working inside the Elnagraph. The Elnagraph was the name on that mechanism that one could use the Elna disks. The Elna sewing machines could be sold without the Elnagraph, if the buyer wants that. Then the Elna sewing machine was a straitstitch sewing machine, but when you wanted it you could have change it to a zigzag and pattern sewing machine with the Elnagraph.
What the company did was making a packet where the buyer could choose (or the money did…?) between diffent levels of functionality with the possibilities to upgrade.
HM_sewing 