screws Flashcards
what type of screws are there
self tapping screws
wood screws
machine screws
what does self tapping screws do
cut their own threads
what does self tapping screws require
a plain hole before use
what is self tapping screws used for
metals and plastics
what does self tapping screws usually have
coarse thread and a tapering diameter
what is wood screws a form of
self-tapping screws
what is required with a wood screw
pilot hole for the shank and possibly a countersink
what are machine screws used for
metal objects or plastics
what does machine screws relly on
-the hole they are being inserted having a threat cut internally
- have an evenly pitched thread and a constant diameter - typically 2mm - 20mm
what do bolts have
a plain shank between the head and the thread
how do you use a bolt
a bolt is inserted into a hole that is slightly larger than itself and the screw threads are secured into a nut with a washer in between
what is the shape of a nut
plain hexagonal
locking nut
what does a wing nut do
allows the joint to be tightened without tools
why are washers an esential part of a boted joint
help to prevent damage to the components being joined
some prevent loosening of the connection
what are the most essential washers
plain and spring washers
