5 Metaphors for screws

The cotton screw was the thing they pressed cotton bales in.

An ordinary screw with two blades is a short piece of a screw of two threads.

Q.What is the nature of Beattle's screw? A.Beattie's screw is an arrangement of the screw propeller whereby it is projected beyond the rudder, and the main object of the arrangement is to take away the vibratory motion at the stern,an intention which it accomplishes in practice.

Q.And seeing that the vessels are of the same mould and power, so that neither can derive an advantage from a variation in that condition, does not the preponderance of the screw vessel show that the screw must be the most powerful propeller? A.-No, it does not.

I cannot say that he had yet come to understand the mechanical power so thoroughly as to see that the lever and the wheel-and-axle are the same in kind, or that the screw, the inclined plane, and the wedge are the same power in different shapes; but he did understand that while a single pulley gives you no advantage except by enabling you to apply your strength in the most effective manner, a second pulley takes half the weight off you.

5 Metaphors for  screws