In Rectangular Hollow Solid Materials (RHS) construction, the hollo bolt (TM) was developed to attach materials such as steel I-beams to this hollow but strong material. Hollo bolt fasteners are used around the world to construct multi-story buildings, bridges, overpasses, and other applications where hollow metal solids are joined. Find out more about how the hollo bolt works below.
Flow drilling is the process of drilling a hole through hollow structural materials, such as rectangular steel tubes, without removing any of the metal. The hole is automatically sealed around its edge because it is made. A tool called a threader winds a thread around the circumference of the hole, allowing it to accept a standard threaded stud as a fastener.
The Hollo Bolt
The Hollo-Bolt assembly has 3 parts, the cone, the body and therefore the threaded bolt. It is pre-assembled and comes during a wide selection of sizes for various fastening requirements. The Hollo Bolt is made of mild steel, with a zinc coating to prevent corrosion. Custom Hollo Bolts can be manufactured from high quality stainless steel. The Hollo Bolt also can be made with a socket or button head, or a countersunk screw head. Hollo Bolts are manufactured in a variety of strengths to provide greater structural integrity than other types of fasteners.
High Clamping Force Hollo-Bolt for Structural Connections
Hollo-Bolt, the first bolt for steel offers a faster alternative to standard SHS/HSS connection methods like welding or through-bolting, enabling contractors to scale back construction time and labour costs.
Hollo Bolt Sizes
Hollo Bolts are produced in sizes from 4 1/2 cm (1 3/4 inches) to eight cm (3 1/4 inches) long.
The larger sizes M16 & M20 (5/8” & 3/4”), are optimised for structural connections and feature a patented High Clamping Force (HCF)mechanism to produce three times more clamping force than the same sized product without the mechanism.
Hollo Bolts Advantages
Due to the consistency of Hollo Bolts, a typical size is often chosen and used throughout the development project, saving time and inventory costs. Hollo Bolt fasteners also minimize the amount of welds that has to be accustomed join metal to metal, reducing costs and increasing worker safety.
Insert Hollo Bolt
The Hollo Bolt is inserted into the holes drilled by flow in both the structural material and therefore the article to be fastened, up to the collar of the bolt. The hex head of the bolt protrudes past the collar. Hollo bolts can be inserted at any material angle from 30 to 90 degrees.
Tighten the Hollo screw
The Hollo Bolt is tightened by placing an open end wrench around the collar to keep it stable, and connecting an appropriately sized torque wrench to the hex head to tighten it. An electric key is being developed that can perform both functions at the same time. By applying torque to the hex head, the flanges on the body of the Hollo Bolt open, anchoring the fastener deep into the hollow structural solid material.
Sealing the Hollo Bolt
Various sealants have been developed for Hollo Bolt to reduce water penetration. Information on these is available from the manufacturer, Lindapter.
How many Hollo screws to use
At least 4 Hollo screws are required to attach a plate to a hollow structural solid. Typically, 8 Hollo screws are used, in a 2 column format, depending on the width of the plate. Measure carefully when placing Hollo Bolts through adjacent faces of the structural hollow solid in order that the bolts don't get contact with one another.