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Nuts, bolts, screws, and washers

This chapter starts with tips on drawing hexagon nuts and hex bolts and comprehensively covers, using illustrations, tables of size and explanations on usage, the majority of metric fixings and fasteners used in engineering today i.e.

A bolt, as you may recall, is a parallel-sided shaft with an inclined plane or helical groove wrapped around it. A screw bolt is similar except that its sides are tapered, not parallel. Alternatively, one could say that a screw is cone shaped while a bolt is cylindrical

 Each description evokes different mind pictures for different people—my pan probably isn't shaped like your pan, and would that be a saucepan or a sauté pan? What is a “fillister” and what does it look like, and just what exactly is a cabinet screw anyway?

 If one is very careful, a nut can be glued (cyanoacrylic adhesives are good for this) to the backside of the oversize mating hole and a so-called “machine screw” be used in place of the original screw. If one has access to the blind side, a nut and “machine screw” might be used in place of the original screw. In desperation, resort to any of a number of specialty devices intended to mount sheet metal and provide a captured machine screw joint.

Washers were originally used for three purposes—to spread the compressive load or anchoring pressure over a larger load-bearing area, to relieve friction, or to prevent leakage. Common flat washers are, as the name implies, a flat disk, usually round and with a hole in the middle, made of metal, plastic, rubber, or leather.