Originally Posted by Jamesbeat

Absolutely agree.
I'm actually from England (moved to the States about five years ago) and the rules are a lot more stringent there, probably because mains voltage is 230-240v.
I believe that thrift stores in the UK have to have electrical devices tested before they can be sold, and they tend not to bother. I don't think a metal-cased sewing machine would pass.

It's all about condition of the insulation, and I'm not for a moment trying to start people panicking.
Your machine is safe as long as you know to regularly check the insulation.

I feel that I will sleep better at night if I ground my machine, so I'm going to do it. I live in an apartment, and my machines are in their cabinets in the living room. I can't secure my machines from my daughter. I remove the needle after every use, and fold the machine into its cabinet when I'm not using it.
As an added level of safety, I'm going to ground it too.

I'll post pictures of my modification so that people can copy it if they are so inclined.