OK... it looks like my comments didn't go over as expected.
Here's what I MENT to ask "randwolfe" to do as a "mental exercise".
For bolts mechanical & structures engineers will think like this...
NOTE: NOT considered in the following discussion are non-structural [light duty] “screws” or “cap-bolts” with very-long or full-threaded shanks intended for simple fastening and mechanical parts installation/clamp-up.
BASIC TYPES: "Conventional" threaded bolts, threaded lock-bolts [Hi-Lok Style], Swaged-collar Lock-Bolts [Stump & Pin-Pull, sometimes called "rivets" in the specs], Jo-Bolt style Blind-Bolts [threaded core-pin to pull swaged-collar] and Pin-Pull Lock-Bolts [deformed shank, formed-bulbed-tail].
RATING: Shear, Tension, Shear-Tension, nominal-use or high-reuse/reinstallation and fatigue.
STRENGTH: 75/90/125/145/160/180/200/220/240(+)-KSI [FTU and/or FSU]
ALLOY: aluminum, brass/bronze/monel/Cu-Be, steel, CRES, A286, Titanium, Inconel 718, MP35, etc,
FINISHES: bare, passivated, phosphated, cadmium-plated, nickel-cadmium plated, chrome-plated, aluminum coated. Note: Cad-plated parts most-likely have post-plating chromate treatment.
TEMPERATURE AND ENVIRONMENT: NOTE... Materials, finishes and locking-patch element material dictate temperature use limitations, typically: Cryogenic [below -100F], -65F [nominal minimum] up-to +250F, +450F, +600F, +900F, +1200F, etc. Dissimilar material interface and specific environments must be considered, such as propulsion VS mechanical VS fixed-structures. Also must consider affect on electrical conductivity... especially where bonding and grounding for EE-EL systems and/or lightning-strikes are required.
Protruding Head Styles: none [Hi-Lok Style], Intrnl Hex, Hex, Hex-domed, 12-Pt, spline, W/WO shoulder washer, tension or reduced shear head, low/nominal/deep “height”.
Flush Head: Tension [full depth], Shear [reduced depth], Domed-Flush, 81/100/120 deg CSK angle and various internal drive-recess styles such as None [HL style], Stndrd-X, Offset-X, Dovetail, etc…
Head-to-shank fillet-radius treatment [forged/machined, cold-rolled and/or ground/polished] and fillet-radius size are affected by head style and performance requirements: IE: small/ground/polished fillet for shear rated or Large/rolled/polished fillets for tension/fatigue rated.
Shank style: NAS518 nominal and nominal-oversize diameters, NON-NAS518 diameters, straight-shank or tapered-shank [IE: Taper-Lok style]; and stepped [shouldered]
Threads: long-thread [~1.7xDia long, +/- 0.3xDia], for tension rated nut &/or good grip-length allowance, or short threads [1xDia +/- 0.3xDia] for light-weight [thin] shear nuts. Thread spec & quality, IE: fine, coarse, rolled, ground, proprietary style, etc… Note: for Hi-Loc style there will be an internal Hex-drive in the thread-tip.
OH Yeah… almost forgot the locking features(?): “None” [plain bolt], drilled-head and/or drilled-threads [for lock-wire or cotter-pins]; added patch-locking element embedded in the threads; and self-locking bolts [IE: positive pin-ball-lock or ring-lock impedance].
Probably missed a few minor aspects... but I think this covers the major categorizing elements
Now: anyone care to try a similar categorizing exercise for “Washers”, “Nuts”, “Pins”, etc??????
Regards, Wil Taylor