Nuts Bolts Screws, Washers and other temporary fixing devices obviously go together with taps and dies. This is a temporary means of fixing objects together.

Nut and bolt

I think I've got a screw loose!

These are of varying lengths and diameters but are all basically the same shape. The head of the bolt is usually hexagonal as is the nut. The length of the bolt  is in two parts, the thread which usually takes up less than half of the length and the shank which is a plain piece of the length of the bolt without a thread. These should be used for connecting pieces of work which have a thickness slightly more than the length of the shank. Holes are drilled in the job so that the bolt passes through, then the nut is screwed on and acts like a clamp to press the pieces of the work together. At this point when the nut is tightened the underside of the head damages the work and for this reason a washer is placed under the bolt head and under the nut If bolted pieces are subject to vibration (cars) then spring washers are placed under the head of the nut. These provide a backwards pressure on the nut and prevent it from coming loose.

Flat washer

Single coil washer

There are two other devices which can help if vibration is a problem.
The coach bolt.
The half locking nut.

Double coil washer

The Coach  Bolt was developed for use when metal was being bolted to wood. The bolt head is rounded and this prevents it from being removed from one side (security) and just underneath the head there is a square part to the shank. When the bolt is tightened the square part of the shank  pulls into the wood and prevents it shaking loose.

A half locking nut is tightened onto the bolt, then the nut is tightened onto the bolt, then the half locking nut is unscrewed back onto the nut which prevents the nut from working loose.
All the components above need a spanner for tightening.

Machine Screws
These are threaded all the way down their length. They have a variety of head shapes so they can be inserted with a screwdriver, (slotted head) Allen  key (socket head) or not have a head so they can be under the surface (grub screw).

Wing nut
These are used when it is only necessary to tighten objects finger tight.

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