Hi, good morning,
The best thing to do for this machine is take it to a local Vacuum cleaner repair shop, most of them also make repairs on sewing machines;-)
They can source the part for you and replace cam and worm drive easily.
This part is extremely difficult to get on your own if you are not a sewing machine technical unfortunately as they don't typically sell this to the end user.
I would check locally for a shop near you for this operation for many other reasons as well;-)
In any case, I will stick with you until this is complete.
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