• Tap bolts do not use a nut to keep them in place.bolt image by martini from Fotolia.com
  
  When you are working on any project, you want to make sure you have the proper fastening devices for the job. Tap bolts, sometimes called a hex bolt, are implemented when you want to use a bolt without affixing a nut on the end to keep it in place. You can find various sizes of tap bolt as well as a couple of different metals that are used to make these fasteners.
  
  

Definition

• A tap bolt is a type of bolt that is screwed into an already drilled hole and stays in place without the use of a nut. These bolts have a hexagon head.
  
  

Other Names

• Tap bolts are also referred to as hex bolts. They are also known as hex cap screws, tap screws and machine bolts.
  
  

Materials

• There are two metal options when choosing your tap bolts. You can choose grade 2 steel tap bolts. These have a zinc plating and are used for normal fastening and do not provide a high strength threshold. If you choose the stainless steel option of tap bolts, you fill find that these are highly resistant to rust and oxidation as well as stronger than the grade 2 steel ones. These are often used in exterior and marine applications.
  
  

Size

• You can find tap bolts in a few different sizes. You can choose between coarse or fine threads on these kinds of bolts. The grade 2 steel and stainless steel tap bolts come in 1/4-inch, 5/16-inch, 3/8-inch and 1/8-inch diameters. There are various lengths available for these bolts. You find tap bolts as small as 1/2-inch long, all the way up to 6 inches in length.