8 years ago


  • Text
  • Fastener
  • Fasteners
  • Products
  • Torque
  • Tightening
  • Bolt
  • Rivet
  • Association
  • Mandrel
  • Industrial
Distributor's Link Magazine Spring Issue 2011 / VOL 34 / NO.2


34 THE DISTRIBUTOR’S LINK Allan Steinbock Allan Steinbock is Vice President of Superbolt ® , Inc. and has been with the company since 1984. He has a Bachelor of Science Degree in Mechanical Engineering from the University of Pittsburgh and is a member of SME and other industry specific organizations. Allan has consulted on thousands of bolting projects and has designed products for a broad range of industries. KEEPING IT TOGETHER WITH SUPERBOLT ® Tackle those challenging bolting applications with Multi-Jackbolt Tensioners Critical large-diameter bolting applications have traditionally been difficult to safely and accurately tighten. The problem is that while the strength of a fastener increases with the square of its diameter, the torque required for tightening increases at an even greater rate – to the third power. Because of this, standard nuts and bolts larger than an inch in diameter cannot be effectively tightened with hand tools. Various methods have been introduced to handle this problem – stud heaters, hydraulic wrenches and nuts, and hydraulic tensioning. Depending on the application, these can be used with success, but these methods present some of their own challenges and may not be effective in certain circumstances. Another solution to the inherent challenges of largediameter bolting is the Multi-Jackbolt Tensioner (MJT). clamping load while using only hand or air tools for installation and removal. This is a huge advantage in that you no longer need cumbersome or expensive tooling to bolt the joint. Worker safety is greatly increased, and also MJT’s boast an accuracy of +/- 5% when calibrated torque wrenches are used. Time savings is another advantage of MJTs. Even though MJT’s have several jackbolts to tighten on each tensioner, they have reduced installation times compared to other methods. The use of air tools also greatly speeds up the tightening process, and in many applications multiple workers can be used. Here’s how they work: To install, you first place the hardened washer over the stud or bolt and then thread the tensioner on, hand tight. With simple hand tools, the jackbolts are tightened uniformly. Turning the jackbolts creates a thrusting of the nut body away from the washer surface, creating bolt tension and imparting a stretch on the main thread. MJT’s flex slightly, adding elasticity to the system which helps keep the joint tight, even when there are temperature changes and fluctuating loads. Common problems such as stud seizure and thread galling are greatly reduced as MJT’s are loaded in pure tension. Instead of having to generate enough torque to tighten an entire hex nut, MJT’s break those torque requirements down by utilizing a series of hardened jackbolts threaded through the body of a round tensioner. This enables the user to generate the needed Every application is different, and it is important to find the right solution for your particular needs. Multi- Jackbolt Tensioners offer a bolting alternative that may be an ideal fit for your machinery. For more information please visit

THE DISTRIBUTOR’S LINK 35 KEY BELLEVILLES, INC. We are the largest Disc Spring Manufacturer! • Complete size range from .236” to 36” O.D. & 3” Thick • Largest Raw Material and Finished Inventory in the World • We manufacture Metric Parts to DIN Specs • Complete Line of Stainless and Inconel Parts • 10,000 Different Sizes in Stock Call toll free from anywhere in the U.S. and Canada at: Phone: 1-800-245-3600 • Fax: 1-800-847-1672 Key Bellevilles, Inc. 100 Key Lane • Leechburg, PA 15656-9531 U.S.A. Phone: 724-295-5111 • Fax: 724-295-2570 • e-mail: Visit Our Website or Call for a FREE Engineering CD

Copied successfully!


OPTION 1: Click on the share tab above, or OPTION 2: Click on the icon (far right of toolbar) and then click on the icon (top right of the page).

Copyright © Distributor's Link, Inc. All Rights Reserved | Privacy Policy