FOR DIY PROJECTS! Common Types of Fasteners – Bolts and Screws Identification List Hex, Wood, Sheet Metal, Machine, Socket (Allen), Lag, Carriage Read more: http://removeandreplace.com/2013/12/20/cheat-guide-chart-for-fasteners-bolts-screws-washers-nuts-and-drive-identification-charts/#ixzz31FseO56C
Just stick a few long bolts and matching nuts and washers in a bag. They screw them on and take them back off. They try to see how many nuts will fit on one bolt. They can make a pattern (one washer, one nut, one washer, one nut).