A bolt is a threaded fastener with a head, designed to be used in conjunction with washer(s) and a nut. Bolts come in many different types and sizes, depending on the situation. Generally speaking, I like working with either 1/2″, 5/8″ or 3/4″ hexagon headed bolts when working with support / framing (i.e. decks, joist-sistering, etc.). Since I work with lumber, I choose to work with a partially threaded bolt vs a fully threaded bolt which is geared towards working with metal.
Because today’s lumber comes from young trees, they tend to be soft so I make sure I use larger washers on both sides (washer with a head + washer with a nut) I believe it to be more secure than using a lag bolt or screws.
As far as the material type is concerned, I found this information from BoltProducts.com:
- Stainless steel bolts: Common choice of hex screws since they don’t need any coating and are corrosion resistant.
- Carbon steel bolts: The most common hexagon screw head bolts are zinc plated for added corrosion resistance.
- Alloy steel bolts: These types of hex bolts are made to withstand an enormous amount of pounds per square inch. They are coated with either cadmium or zinc plating to protect them against corrosion.
An online merchant called BoltDepot.com has tons of useful information, including some nifty size guides that can be printed out. Check them out below: