How to choose a right screw bolt?

What are the types of screw bolts?
Wood screw bolts are usually made of steel. Brass, nickel, bronze, or copper screw bolts should be used if there is potential for corrosion. For optimum performance, you need to drill it first.

Use sheet metal screw bolts to fasten pieces of metal together. Sheet metal screw bolts form threads in the metal as they are installed. There are several different types. Pointed panhead screw bolts are coarse-threaded that are used in light sheet metal. Blunt panhead screw bolts are used for heavier sheet metal that are available in gauges from 4 to 14 and lengths from 1/4 inch to 2 inches.

Partial roundhead screw bolts have finer threads in soft or hard metals. Self-tapping roundhead screw bolts are used for heavy-duty work with thick sheet metal, which are available in diameters from 1/4 inch to 2 inches and in lengths from 1/8 to 3/4 inch.

Machine screw bolts are blunt-ended screws used to fasten metal parts together. They are also made with coatings, such as brass, copper, nickel, zinc, cadmium, and galvanized to deter rust. Machine screw bolts have four basic types of heads, that are, flathead, oval-head, roundhead, and fillister-head.

Lag screw bolts are heavy-duty fasteners, driven with a wrench and used for fastening. The anchors are inserted into holes drilled in the masonry. Then the lag screw bolts are driven firmly into the anchors.