Fastener Guides
Notes for engineers and buyers specifying custom screws and bolts.
Types of screwsTypes of screws and bolts explained: machine screws, hex bolts, socket head cap screws, thread-forming screws and set screws, plus head styles, drive types and thread types.Bolt property classesWhat bolt property classes 4.8, 8.8, 10.9 and 12.9 mean, how to read tensile and yield strength from the numbers, stainless steel classes A2-70 and A4-80, and selection notes.Fastener finishesCommon fastener finishes compared — zinc plating with trivalent passivation, black oxide, nickel, zinc flake and passivation — plus hydrogen embrittlement and thread-fit notes.