The Bolt page needs to be extended to include common cases; the sort of stuff that normal readers of news:uk.D-I-Y already know approximately.
Terminology : difference between bolts and screws (nouns), the terminologically-unfortunate fact that small bolts are commonly tightened with screwdrivers.
Sizes : B.A. not yet fully extinct; metric sizing; deciding the sizes of a screw-hole (in wood?)
Can it be rightly said that anything that uses a nut must be a bolt or a stud or the threaded end of a rod? If a threaded joiner does not use a clearance hole, must it be a screw?
Use and names of washers - plain, wavy, gnarly, solder tags.
It might be interesting to give the sizes of the smallest and largest bolts that are regularly manufactured and/or used in an ordinary home!