Electric irons are made of iron, and since iron is a good conductor of electricity, if you touch it with your bare hands you would get shocked. Plastic doesn't conduct electricity and is one of the best insulators, so it would be safe to use plastic handles while ironing. Even if the ironing machine isn't electric, the machine is bound to get heated, and if you touch it to use it, you would burn your hand, so no matter the type of ironing machines, you always need a plastic handle.
A person who plans machines is called an engineer. People who make them can have a number of titles including mechanic and millwright.
A compound machine.
Circular is one type. There are manual and hand crank knitting machines.
An ironing board cover that is only fabric would be more of an insulator between the wood or metal surface of the ironing board. An ironing board cover with a foam backing and an aluminum type fabric on top would be both an insulator as well as a conductor of heat, to have heat distribute more evenly through the item being ironed.
Calpurnia is referring to the act of ironing or pressing clothing made from linen fabric. Linen is a type of cloth made from the fibers of the flax plant, and it typically requires ironing to remove wrinkles and create a crisp appearance.
Crowbars are a lever.
lever
A lever.
make stuff
The main thing that I remember about the clothes in the fifties is natural fibers (ahhhh) and ironing (oooh).
the types of machines are simple machines and compound machines