Understanding the principles of torque is much more involved than simply cranking down on a nut until you hear a click. However, old school instruction on torque might have been just that—once you hear the click, the bolt is properly torqued. But is it?

Torque CertificationRecognizing a need for more training in the area of torque within many industrial markets, Snap-on Industrial has developed a torque certification pro-gram. The goal of the program is to ultimately give technicians the training and education they need to understand all facets of the use of torque wrenches, making them more effective and proficient on the job. The tooling manufacturer has partnered with the National Coalition of Certification Centers (NC3), which is a network of education providers and corporations that supports and validates new and emerging technology skills in transportation, aviation and energy industry sectors, to help facilitate torque certification as well as curriculum certifications in other areas including diagnostics, vehicle information systems and multimeters. The role this type of certification brings to indus-trial markets is conformity and an across-the-board standard for the partnering technical schools to teach in-depth instruction on tool use as well as theory and application. Upon completion of the torque certifica-tion course, technicians become certified in the proper use of torque products—making them more produc-tive and well-rounded professionals. The certification courses in torque and other disci-plines serve as an enhancement or accent to the cur-riculum taught in today’s technical classroom and labs; they’re not an add-on, but rather an integration of the most current technology to provide students and technicians real-world experience. The torque certification is a 24-hour course divided into three areas: theory, application of torque and cor-responding safety steps and proper hydraulic torque. Theory goes into the basics of what different fasten-ers do, how to identify bolt grades, metal grades

Andy Lobo, Director of Product Management and Development

Snap-on Industrialwww.snapon.com

Understanding the Principles of Torque

June 201298 Fastener Focus June 2012

and the science and math that’s at work in fastener protocol. The second section is the application of torque, which shows technicians how to use torque tools, how to make proper calibration equations and how to make wrench adjustments. Additionally, stu-dents have access to a test bench where they actually apply torque techniques, processes that are analyzed by a dedicated computer system integrated into the workbench.The third module is dedicated to hydraulic torque application. This course work is for really large fas-teners, some of which must be torque in confined spaces. The application of hydraulic torque requires its own skill sets including knowledge of hydraulic systems, proper fastener fitting for these specialized applications and large-fastener/equipment safety considerations.

Torque in ActionThe physics of torque involves a twisting or wrench-ing effect exerted by a force acting at a distance on a body, equal to the force multiplied by the perpendicu-lar distance between the line of action of the force and

Technician applying proper torque in a critical application.

June 2012 Fastener Focus 99

measurement; follow calibration schedule and guide-lines for torque wrench.

SummaryThere is a perception that applying torque to a fas-tener is intuitive, anyone can do it. Well, anyone can do it, but the ability to do it properly is what makes the difference. Torque certification aims to give technicians a comprehensive understanding of torque—and the ability to properly apply it on the job. The certification is being offered at technical schools across the country including Lakeshore Technical College, Cleveland, WI, USA; Gateway Technical College, Kenosha, WI, USA; and the multi-campus Frances Tuttle Technology Center in Oklahoma. Being certified in torque gives technicians the added training and awareness that will pay dividends down the road in higher equipment uptime and reduced maintenance costs. For additional information contact the author at Andrew.r.lobo@snapon.com

Company Profile...Snap-on Incorporated, located in Kenosha, WI, USA, is a leading global innovator, manufacturer and marketer of tools, equipment, diagnostics, repair information and systems solutions for profes-sional users performing critical tasks. www.snapon.com

The Revolution Has Begun!

Replace Your Old Flywheel

Rivet Machines

Headquartered in Aurora, IL, USA, Valley Fastener Group, LLC, is your single-source supplier of cold formed fasteners, rivets, weldnuts, rubber parts, springs, rivet machines, tooling, automation and related engineered solutions. Our customers look to us for innovations related to using and installing fasteners. Along this theme, we introduced our new Revolu-tion Rivet Machine, the latest in impact riveting and clinching. With no linkage and no flywheel, the Revolution Rivet Machine features fewer moving parts than competitors’ “old fashioned” flywheel rivet ma-chines. Fewer moving parts means reduced wear on system components, less operating costs and longer machine life. Available in bench-top or pedestal style, the Revolution Rivet Machine can also be utilized in fully automated work stations. The level of rivets in the track is monitored electronically, permitting rivets to feed from the hopper only as required, preventing jam-ups. Featuring a compact solid steel (not cast) design, this modern cam-operated machine provides a smooth, fast cycle (1/3 second cycle time) and features stan-dard an 18" (457 mm) throat depth. The simple and easy-to-use Revolution Rivet Machine requires no oil, grease or lubrication. Super quiet, the machine runs on single-phase 110 VAC with no air required. The user simply plugs the machine in and begins to clinch rivets, eyelets, or other clinch type fasteners. The standard 8" (203 mm) hopper incorporates a lined backing plate for reduced wear. Engineered for easy maintenance, reduced wear and reduced jams, the Revolution Rivet Machine is easily the most flexible assembly machine on the market today.The machine is capable of clinching very small diam-

Hal Stetson, Vice President Valley Fastener Group, LLC

www.valleyfastenergroup.com

Revolution Rivet Machine from Valley

Fastener Group features less moving parts,

unlimited throat depth and the mechanical advantages of CAM

technology.

February 200776 Fastener Focus

eter on up to 1/4" (6.4 mm) steel semi-tubular rivets as well as a variety of sizes of solid rivets.After you have looked at the Revolution Rivet Machine, you will realize that the old-style flywheel machines are a thing of the past.

Expansions Fuel Growth at Valley Fastener Group...With two recent expansions, the Valley Fastener Group, LLC is uniquely positioned to offer its customer base an expanded line of special cold formed fasteners and rivets. Additionally, it pro-vides customers with global sourcing and blended programs, rubber parts, weldnuts, springs, en-gineering and technical assistance, assembly equipment and outsourced fastener assembly. Valley Fastener Group corporate and the Valley Rivet Division are located in Aurora, IL, USA. Cold headed special fasteners and screws are produced at the Forgo Fastener Division facility in Melrose Park, IL, USA.Forgo is currently adding 4000 ft2 (370 m2) to its production facility.The North Coast Rivet Division located in Elyria, OH, USA, recently completed a 4000 ft2 (370 m2) expansion. All group divisions work closely with customers to ensure that the best solutions are specified for their applications. www.valleyfastenergroup.com

the center of rotation at which it is exerted. In other words, torque is a measure of how much force acts on an object that causes that object to move. When torque is applied to a fastener, essentially what is happening is that the fastener is stretching ever so slightly as the nut is turned. The fastener is being elastically pulled (or stretched) in one direction as the nut is turned. Tension in the fastener increases as the nut is turned and friction under the head of the fastener holds the fastener in place.As torque is being applied to a nut from a torque wrench, technicians can feel when the targeted torque pound setting is nearing due to the amount of effort needed to turn the wrench. This point of the torque process is where technicians can get in trouble by applying too much torque to a fastener.For example, if a technician keeps cranking after the targeted torque setting is reached, the fastener can be permanently deformed and elongated, i.e., stretched beyond its limits. This is called the yield phase. If using an electronic wrench (such as Snap-on’s Tech-wrench) or a dial wrench during the yield phase, the technician may notice a decrease or leveling of indicated torque as the nut continues to be turned. When this occurs the bolt needs to be replaced. Even a little turn of the torque wrench can cause the fastener to be stretched beyond its limits. That’s why technicians need to turn the torque wrench slowly, es-pecially when the targeted torque setting is in range, so as to not over torque the fastener.Subsequently, an under-torqued fastener can also pose problems. Vibrations can occur when a fastener is under torqued and not properly secured. The fas-tener could start to come loose from the nut over time, compromising the integrity of the assembly. Also, some fasteners do develop microscopic cracks dur-ing the manufacturing process. Vibrations can cause the cracks to grow and cause damage to the fastener.

Before torque is applied to fasteners and bolts, techni-cians should ensure they are well cleaned and dry. Most torque recommendations are based on clean and dry specifications, meaning the fasteners are clean and dry. If fasteners or nuts are dirty from rust, paint, etc., they should be cleaned with a wire brush or replaced. Fasteners that are clean and dry can hold a higher tension per ft-lb of torque than one that’s dirty. Check with a manual for specific torque specifications prior to applying torque to a fastener. Other techniques to be aware of when applying torque: always follow the recommended torque sequence; don’t use a torque wrench to break a bolt loose, use a breaker bar; hold the torque wrench in the center of the handle for proper use and accurate