I sew nearly every day in the afternoons. I have an older but sturdy sewing machine right next to my computerized model in my studio. When I sit down to sew, all the children come to be with me. They take turns on the old machine. Even my 3 year old boy takes his turn.
Are you wondering if it's safe? There is a danger involved, but death or permanent maiming is unlikely. That makes it safe in my book. I do talk to them about how to respect the machine and where to place their fingers. I wedge a dry dish sponge in the foot pedal to make speed sewing difficult. I'm also right there beside them, though usually working on my own project. Their favorite thing is to sew on lined notebook paper to see if they can stay on the lines. They have gotten better at controling the machine than most adults.
Heather sat down to sew last night and I paused to watch her for awhile in awe. Look how professional her hand placement is. She's 5! She was concentrating very hard and turning her paper in strange loops. I wondered what she was doing--she wasn't staying on the lines. But I said nothing and just watched.
After a while she stopped with a satisfied look and a happy smile.
I'm not sure I could do that as well!
And I guess this shows my philosophy of parenting. If it's not illegal, immoral, damaging to property, deadly, or permanently maiming--I let them go for it. And I remember my mom's famous phrase she told me as a girl when I asked if I could do something..."Just clean up after yourself."