Norbar Torque Tools in Aerospace and Aviation

Norbar Torque Tools Ltd.
Beaumont Road
BANBURY
OX16 1XJ
United Kingdom

Tel: +44 1295 753 616
Fax: +44 1295 753 643

email: pbrodey@norbar.com
web: www.norbar.com

The aviation industry indirectly brought about the creation of Norbar and continues to be a key market. The Rolls Royce Merlin engine that powered most of the Allied fighter and bomber aircraft in World War Two can perhaps lay claim to being Britain’s first massed produced, high precision machine. It was recognised that having honed the cylinder bores, this precision could be undone through the uneven tightening of the cylinder head. Torque tightening was therefore specified and Bill Brodey, co-founder of the North Bar Tool Company (Norbar), was commission by the Government to start manufacture of torque wrenches in England in 1943.

Norbar now supports the aerospace industry with a range of products and services, across the world and within: airlines, aircraft manufacturers, aircraft maintenance facilities and research organisations.

Torque Wrenches

Norbar torque wrenches are recognised throughout the world for their quality and precision. Torque wrench spare parts are freely available and Norbar distributors exist in most countries, qualified to repair and calibrate the tools.

Norbar wrenches are designed to hold their calibration over many thousands of cycles. However, when they finally do require adjustment, this can normally be achieved without completely dismantling the wrench. This is unlike the so called ‘rocking cube’ mechanisms favoured by many manufacturers in which the ‘cube’ will at some point have to be replaced. The ‘cube’ mechanism also makes it virtually impossible for a wrench to hold its calibration simultaneously in the clockwise and anticlockwise directions. Most Norbar wrenches achieve anticlockwise torque control simply by ‘pushing through’ the square drive in the ratchet head. The mechanism always works in the same direction and so only requires calibration in one direction.

Where Norbar utilise plastic handles on their wrenches, those plastics are always selected for resistance to aviation hydraulic fluids. All Norbar wrenches are tested for corrosion resistance in hydraulic fluid before release onto the market.

Torque Multipliers and Pneumatic Torque Wrenches

Norbar’s hand operated Handtorque™ torque multipliers and pneumatic Pneutorque® wrenches span a torque range from 100 N.m to 100,000 N.m (approximately 70 to 70,000 ft.lbs). Although many of Norbar’s multipliers have a torque output too high for most aerospace applications, there are certain niche applications in which quality torque multipliers are invaluable. One of these is the attachment of helicopter rotor blades and Norbar has built up extensive experience, mainly with Boeing Chinook helicopters serving with the British and Dutch Air Forces.

Other ideal applications are aircraft wheel rim bolting, high torque turbine applications and undercarriage removal/replacement.

Torque Measurement and Calibration

Norbar torque calibration instruments are trusted to be the equipment of choice for air forces, airlines and OEMs around the world.

Norbar’s torque measurement range starts with simple to use but accurate testers that could be sited line-side in production facilities or in aircraft hangers. Their main purpose is for performing regular torque wrench confidence checks. The range progresses in sophistication and accuracy through to instruments that are suitable for the fully equipped torque calibration laboratory.

Many aerospace customers wish to have control over the entire calibration hierarchy for their torque calibration equipment. Norbar have supplied many airlines with beam and weight calibration master systems for the calibration of torque measuring devices.

All Norbar transducers up to 6800 N.m (5000 ft.lbs) are supplied with a UKAS accredited calibration certificate. Since 2004 the National Institute of Standards and Technology (NIST) have confirmed to the FAA that certificates issued by UKAS accredited laboratories, UKAS being a member of the Mutual Recognition Agreement (MRA), can be regarded as equivalent to NIST traceable.

Norbar is also UKAS accredited for the calibration of electrical torque indicator displays. Issuing the display with its own calibration certificate ensures that each element of the system is fully traceable and interchangeable.

Torque Calibration Services

Norbar have now set up torque calibration laboratories accredited by the local standards body in: UK (UKAS), Australia (NATA), USA (NVLAP) and Singapore (SINGLAS). A laboratory has also been set up in Shanghai, China with accreditation expected in 2009. The laboratories are equipped to the same standard as the factory based laboratory ensuring consistency and repeatability between the laboratories. All of the laboratories operate to BS EN ISO/IEC 17025:2000 which sets standards for the technical competence of laboratories.

Ultrasonic Stress Meter – USM-3

In certain critical bolting applications, factors such as friction or joint geometry are such that the measurement of applied torque alone will not provide the degree of accuracy necessary to control the preload of the fastener. In such applications, ultrasonic measurement of fastener elongation and/or load has frequently proven to be the most accurate, reliable and cost effective solution.

The USM-3 uses state of the art hardware and software to provide a complete system for measurement, recording and control of fastener tension in the most demanding applications.

Norbar Torque Tools Ltd.
Beaumont Road
BANBURY
OX16 1XJ
United Kingdom

Tel: +44 1295 753 616
Fax: +44 1295 753 643