Generally, in the majority of applications, the reliability of the joint is dependent upon the bolts ability to clamp the parts together. Adequate clamping prevents relative motion between parts of the joint and leakage from joints containing gaskets. Measuring a bolts clamp force is difficult, especially under production assembly conditions.

The clamp force generated by a bolt can be indirectly controlled by regulating the applied torque. This method, known as torque control, is by far the most popular method of controlling a bolts clamp force. The initial clamp force generated by the bolt is frequently called preload.

There is a link between the torque applied to a bolt and the resulting preload. A problem exists in that friction has a large influence on how much torque is converted into preload. Besides the torque required to stretch the bolt, torque is also required to overcome friction in the threads and under the nut face. Typically, 10% to 15% of the torque is used to stretch the bolt. Of the remaining torque, typically 30% is dissipated in the threads and 50% to 55% under the nut face. Because friction is an important factor in the relationship between torque and preload, variations in friction have a significant influence on the bolts preload. Different bolt surface finishes generally have different friction values.

The torque required for a socket head screw will not be the same as that required the same size standard hexagon bolt. The larger bearing face of the standard bolt will result in an increased torque being required compared to a socket headed screw. This is because more torque is being dissipated between the nut face and the joint surface.

Stresses indicated into a Bolt: When a bolt is tightened the shank and thread sustain a direct (tensile) stress due to it being stretched. In addition, a torsional stress is induced due to the torque acting on the threads. These two stresses are combined into a single equivalent stress to allow a comparison to be made to the bolts yield strength. In order to effectively utilize the strength of the bolt, yet leave some margin for any loading the bolt would sustain in service, an equivalent stress of 90% of yield is commonly used. It is this approach that is used in this guide.

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Mountz, Inc. introduces a new line of cordless screwdrivers to the lineup branded FlexPower by Mountz. Built for torque control and durability, the cordless torque tools are built around the 10.8V and 14.4V high capacity lithium-ion battery platforms. These rugged cordless assembly tools increase productivity and enhance product quality through precision torque control and user comfort. The cordless screwdrivers are ideal for applications where air or electric power is not easily accessible. The cordless torque screwdrivers automatically stop when the preset torque has been reached.

In the demanding fastening applications where speed and maneuverability are key assembly requirements, the cordless tools operate at lengthy periods between charges and are flexible for tight space applications. The FlexPower battery screwdrivers feature an ergonomic hand grip designed to improve control and reduce fatigue in long run applications.

The cordless screwdrivers are built with LED indicators that provide an audible and visual alarm signal for the operator as he/she achieves the preset torque value. The LEDs will provide a signal to the operator if the preset torque was not achieved, as well as provide an early warning of a low battery. Mountz, Inc. has improved the technology of cordless screwdrivers with an unique mechanism designed to automatically shut-off the tool when the battery has less than 25% of the charge, ensuring the quality of the fastening torque.

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Every year, Mountz Inc. donates turkeys to local charities before Thanksgiving. With the holiday season closing in fast, Mountz Inc. donated 25 turkeys to Most Holy Trinity, a local church in San Jose, CA. It is because of our community we are able to become successful and we want to give our thanks to them.

“It is the responsibility of any business in its community to give and to encourage its employees to give to those less fortunate. If one cannot give monetarily, one can give time, one can sweep the closet or cupboard for extra clothing or canned food – something that can be used by those in need.” said Brad Mountz, President & CEO of Mountz, Inc.

We hope that our donation to our local community will create warm memories of this holiday season and also help them through the current difficult times. Mountz Inc. wishes everyone a safe and cheerful Thanksgiving. Happy Thanksgiving everyone!