When you’re in need of a structural fastener that offers more muscle and adaptability than a common rivet or weld, then your choice should be a blind bolt. Developed to establish strong connections that common rivets or hex bolts aren’t capable of achieving, blind bolts have been around for decades and used for repairing and fabricating. They were developed to solve a major problem –- forging a strong connection.
Blind bolts are versatile because they can be installed from one side through pre-drilled holes and accomplishes a complete lock without access to the other side of the bolt, thus the name. They are a perfect fastener for connecting box sections and girder cavities quickly and easily with unprecedented strength.
The common Blind Bolt is installed using an adjustable wrench and flat head screwdriver, no special tools required. The blind bolt is put in to a pre-drilled hole. The solid connection is achieved through simply turning the bolt 180 degrees and the toggle will come out and you pull the bolt flush so the toggle is now set to the inside of the connection point. Hand snug the nut, and then take your flat head screwdriver and place in the groove to hold the bolt in place while you tighten with a wrench to the recommended torque value.
The grip length is the distance from the under head-bearing surface to the first thread of the shaft. The grip is the total thickness of the material being joined. The grip length should be a few thousands of an inch less than the actual grip. Each Blind Bolt will have a minimum and maximum grip range which give our bolts great flexibility for installing.
There are a number of elements that determine which blind bolt to use in a particular application. These elements include:
- Strength of the bolt required
- Clamping Thickness (Grip Range)
- Diameter of the bolt desired
- Hole Sized Drilled in Steel
It is important for you to know the clamping thickness and hole size. You also want to know the tensile strength of the bolt when deciding which one to use. The width of the bolt and the material used in its fabrication determines tensile strength.
Blind bolts come in an assortment of thicknesses and lengths. So, it is essential that you select a bolt that is large enough to perform as well as deliver maximum strength.
Another advantage of the blind bolt is that the bolt can be removed and pulled out of the structure. Whereas other products would need to be pushed into the hollow section for removal.
In many environments corrosion is a factor because of nearby water, an abundance of rain or excessive moisture. The blind bolt is ideal to use in conditions that make corrosion a possibility because they are made of materials that resist moisture.
By now, it should be apparent that you need to have knowledge of the specifications of the many blind bolts that are available. Check appropriate specification charts that give details about the blind bolts that are available.