Fastening Nuts and Bolts: The Basics

A screw with bolt and washer.

Nuts and bolts are the basic building elements that hold materials together. While you may think that such hardware would require no explanation, their proper use is not as obvious as it seems.

To begin with simple definitions, nuts are internally threaded, thick-edged fasteners. They're usually hexagonal in shape and designed to tighten or assemble with at least, but not limited to, two components. They work in coordination with bolts, which are externally threaded shafts of varying lengths and thicknesses. A third component—washers—are generally used along with a nut and bolt fastening. When using nuts and bolts, most important is that you make sure the threads match each other when fastening them together.

When twisting the nut onto the bolt, you can feel it when the grooves line up inside the bolt. To get an exact fit when purchasing nuts and bolts or matching them up, there is a formula that is used throughout the industry.


For example, a bolt with the series of numbers ¼-20 x ¾ means the bolt has a diameter of a ¼ inch, 20 threads per unit, and is a ¾ inch long. Other readings include #4-40 x 1, with the #4 as the diameter. For metric readings, there will be an ‘M’ preceding the first number.

Steps for Fastening Nuts and Bolts

A piece of wood with a hole being drilled into it.

Bolts, nuts, and washers come in a variety of sizes (width and length), types (standard and locking) and styles, but the basic steps for fastening the trio together is generally the same process. For this project, we’ll use an example of two 12-inch pieces of wood each with a hole drilled completely through the material near the top that needs to be fastened together with a bolt.

Step 1

The first thing to do is select the type and the size of the bolts, nuts, and washers that are appropriate for the example project. Determining factors include the type of material used for the example project, the type of fastening/connection that is needed, how strong the bolt needs to be to secure the connection, how many nuts, bolts, and washers are needed, or any specific manufacturer requirements that may be necessary. These are just a few of things to consider when you do an actual project. If you aren’t sure about what type or size is correct, ask a qualified representative at a home improvement center for help.

Step 2

Select a bolt and a washer. Slide the washer onto the end of the bolt and push it as far as it will go until it reaches the head of the bolt.

Step 3

Using the example project of two wood pieces, place the two pieces side by side and align the drilled holes so the bolt can be inserted between the two to make a connection.

Step 4

Take the bolt with the washer in hand and push the threaded shaft through the hole in the first piece of wood and continue pushing on through the second hole. The one piece of wood will have the washer and bolt head protruding from its hole while the threaded end of the bolt will be protruding from the hole of the second piece of wood.

Step 5

A pile of hardware.

Take another washer and place it on the threaded shaft protruding from the second piece of wood. Push the washer all the way up until it is flush with the wood material.

Step 6

Place the nut on the end of the threaded shaft. Be sure the washer is aligned properly with the threads on the bolt and then begin to twist it clockwise until it reaches the washer. Tighten the nut with your fingers to secure it.

Step 7

Complete the fastening process by using a wrench that fits the size of the nut. Place the wrench on the nut and tighten it firmly so there is no wiggle room between the nut and the washer.