2. Yes, zip screws are actually motors. It is the simplest
type of motor. It is also a linear actuator, which is an
actuator. An actuator is a type of motor for moving stuff.
Hence, a screw is a motor. A linear actuator converts
circular motion into forward motion in a straight line. A
screw has a grooved head and a shaft with a helical
external groove.
3. The world is full of tiny linear actuators. There are two
types of screw head. The straight kind has a single
groove and is manipulated into place with a straight
screwdriver. The other type has two grooves
perpendicular to one another. This is called a
"crosshead" or Phillips screwdriver. It is used because of
its self-centering activity. You can sometimes use a
straight screwdriver to set a crosshead screw. The man
credited with its invention was Henry F. Phillips (1890 1958).
4. It is surprising how we take the crosshead screw for
granted and never give a thought to the man who
patented it. Born in Portland, Oregon, Phillips bought
the rights to the device from its original inventor, John P.
Thompson. Phillips tweaked the design and got the
patent for it.
5. One of Phillips' first customers, in 1936, was General
Motors, who put it to work on its Cadillac assembly
lines. He sold the patents to Ford Motor Company in
1945 for approximately $5 million. Phillips died in 1958.
6. Now, while a phillips head screw can be set with a
straight, ordinary screwdriver, it doesn't work very well
the other way around. A phillips head screwdriver is
useless for screwing a single-grooved screw. This is
because it can't get a grip on the single groove. Most
people give up and use a small coin, like a dime or a
British half penny if they have one lying around. A table
knife also works in a pinch if you are desperate.
7. A screw is different from a bolt, although they perform a
similar function, holding stuff together. A bolt has
external threads at one end and a head at the other. The
bolt is slipped through two holes and a nut, which has
internal threads, is wound around the external threads
until the whole apparatus fits together tightly.
8. A screw, on the other hand, does not require a nut to
hold it in place. Say you are going to hang a painting.
First, a hole is drilled, for example, in a wall. Then a rawl
plug, a screw-sized plastic is fitted into the resulting
hole. The screw is then driven in, first by hand, then by
screwdriver, but not all the way in. The painting is hung
onto the part of the screw that is sticking out of the
wall.
9. Zip screws are used mainly for sheet metal (the kind
used for ducting) and guttering. These have an especially
sharp point that is easy to pierce through thin, soft
metal. It gets its name because it zips straight through.
If, on the other hand, you want to work with a harder or
thicker sheet of metal, then you would use a TEK screw.