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SPRING 2019

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Distributor's Link Magazine Spring 2019 / Vol 42 No2

70 THE DISTRIBUTOR’S

70 THE DISTRIBUTOR’S LINK Anthony Di Maio Anthony E. Di Maio attended Wentworth Institute and Northeastern University. In 1962 he started working with Blind Fasteners as Vice-President of Engineering & Manufacturing for two blind rivet manufacturers. He has been Chairman of the Technical Committee of the Industrial Fasteners Institute (IFI) and is still involved in the writing of IFI specifications. In 1991, he started ADM Engineering and is working with Fastener Manufacturers developing new fasteners and special machinery. He can be reached at ADM Engineering, 6 Hermon Ave., Haverhill, MA 01832; phone and fax 978-521-0277; e-mail: tdimaio@verizon.net. RADIAL GROOVES ON MANDRELS Many people have asked me “why do blind rivet manufacturers add radial rings, Grooves or serrations to mandrel diameters of blind rivets.” These radial grooves are added to the mandrel circumference to ensure that the griping jaws of the blind rivet setting tool do not slip when setting the blind rivet. These radial grooves are put on the mandrels of high tensile blind rivets such as stainless steel and structural blind rivets. The radial grooves on the mandrel ensure that the pulling jaws will grip the mandrel, by the teeth of the pulling jaws are in the radial grooves of the mandrel. The pitch between the radial grooves match the pitch between the teeth of the pulling jaws, thus giving the pulling jaws a good grip on the mandrel of the blind rivet. Even if the pulling jaws are slightly worn, the teeth of the pulling jaws will still grip the radial grooves of the mandrel. Jaw Compression Spring Jaw Case Jaw Pusher Pulling Jaws Nose Piece FIGURE 1 The pulling or griping jaws of the blind rivet setting tool must first grip the mandrel diameter and then, as the setting tool starts to pull the mandrel, the pulling jaws penetrate the mandrel for a locking grip. The pulling jaws have a 10 degree angle on their outer surface and they are in a 10 degree tapered hole. The more the pulling jaws pull the mandrel, the deeper the jaws penetrate the mandrel. The pulling jaws must first grip the mandrel with the teeth that are on the pilling jaws. The first initial griping is done by the sharpness of the teeth of the pulling jaws and allows the pulling jaws to penetrate the mandrel when the setting the blind rivet. If this initial griping does not occur, the pulling jaws will slip when the rivet setting tool attempts to set the rivet. CONTRIBUTOR ARTICLE Fig 1 Fig 2 FIGURE 2 The higher the mandrel tensile strength, the harder the surface of the mandrel. Structural blind rivet and all stainless and stainless body and steel mandrel blind rivets all have high tensile strength mandrels. Radial grooves on high tensile strength mandrels, lengthens the setting life of the pulling jaws. Annealing (Heat Treat) Blind Rivet Bodies Annealing (heat treat) blind rivet bodies is important when manufacturing blind rivet bodies. When rivet bodies are produced, either stamped from sheet stock or extruded from wire, a large amount of work hardness is created in the formed rivet body. CONTINUED ON PAGE 134

ZAGO MANUFACTURING INC. DEALING WITH PRESSURE THE DISTRIBUTOR’S LINK 71 21 East Runyon Street, Newark, NJ 07114 TEL 973-643-6700 FAX 973-643-4433 EMAIL info@ZAGO.com WEB www.ZAGO.com Engineers are often unclear about the utility of selfsealing fasteners versus ordinary screws, nuts and bolts. Why use a more expensive sealing fastener when a standard fastener or a non-grooved fastener with an o-ring or washer will do? The reason - pressure. Pressure is everywhere. Even at sea level atmospheric pressure is equal to 14.70 pounds per square inch or 1.03 kilos per centimeter. Inside equipment, particularly hydraulic and pneumatic equipment, pressure rises quickly after activation. Similarly, as an airplane rises in the air, outside pressure increases; and as a robot dives below the surface of the sea pressure increases precipitously. Standard fasteners simply cannot withstand this pressure. Leaks of gases and liquids are sure to follow leading to equipment failure and environmental degradation. A mechanism is necessary to counteract this pressure. The best possible mechanism to prevent leaks due to pressure, and the infiltration or egression of liquids and gasses, is a fastener with an O-ring and a groove. Using a simple o-ring or washer to seal, without a groove to calculated to relieve pressure will inevitably lead to equipment failure. An accurately engineered groove will absorb the pressure within and outside of equipment that is applied to the o-ring causing the o-ring to spread and penetrate any open space where leaks might occur. The demand for sealing fasteners has never been greater. As equipment becomes more expensive and sophisticated, the need to keep it contaminant free is critical. Also, as environmental concerns grow, the need for an environmentally sustainable solution to equipment failure is paramount. ZAGO self-sealing fasteners are sustainable in the broadest sense of the word. They are conflict mineral free, ROHS and REACH compliant, as well as compliant with California proposition 65. They are the ideal solution for long term industrial and mechanical sustainability and ideal for sealing electrical enclosures and equipment subjected to the elements. At ZAGO we are the acknowledged leader in the manufacture of self-sealing fasteners with over 25 years of problem solving engineering experience. BUSINESS FOCUS ARTICLE ZAGO MANUFACTURING INC

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