down scaling | Model Engineer
Fastenings are not so difficult. Most won't be far off the 3.5 / 5 ratio, though you'd probably want to use screws with size-smaller heads in many areas for appearance or accessibility - a spanner takes up a lot of room! A rough guide to the right area is to assess the nut and bolt sizes in full size, and bear in mind they had to be manipulated by blokes with spanners. Looking at preserved machinery, a lot of the ordinary fastenings were no more than perhaps 3/4 diameter; much above an inch was usually for major, fitted bolts holding parts like cylinders to frames; or specials on marine-engi...