Tag » Calibration

NORBAR: A POTTED HISTORY (PART 2)

Picking up were part one left off, another Dr. Merritt design was the ‘Slimline’ torque wrench mechanism. Prior to the ‘Slimline’, all Norbar torque wrenches used an external, break-back mechanism. The ‘Slimline’ was the first Norbar design to completely contain the mechanism within the body tube of the wrench, hence the ‘Slim’ reference. The ‘Slimline’ torque wrench was launched in 1963 and some models remain in production today. Variations in this mechanism underpin most of Norbar’s current torque wrenches.

Norbar has manufactured torque testers for almost as long as they have manufactured wrenches. The earliest types employed a simple spring balance attached to a pivoted bar. The next evolution was to utilise a hydraulic cell and hydraulically activated gauge. The ‘Static Torque Meter’ was much more compact than the earlier versions and were easier to use because this system avoided the needle fluctuations of the spring balance type. This product enjoyed a near 50 year life span before finally being rendered obsolete by electronic measurement methods. The first reference to a Norbar electronic torque analyser is dated 1967. The display unit, incorporating an analogue gauge similar to a Voltmeter, was attached by a cable to a separate, strain gauged torque transducer. Forty five years later, this essentially remains the method of measuring torque although the electronics are now based on single-board computer technology with such features as colour display and touch sensitive screen.

1969 was a landmark year and saw the company’s first address change bringing with it the official change in name from ‘The North Bar Tool Company’ to ‘Norbar’ (which had previously been used as a telegraphic address). The new premises on Swan Close, Banbury, were originally 9,000 sq.ft but were extended twice before being outgrown and Norbar moved again to Beaumont Road, Banbury in 1984. A major extension to this site in 1989 took the floor area to 45,000 sq.ft and further extensions and mezzanine work give a current day total of 52,000 sq.ft of production and office space.

In November 1989, Norbar became the first torque tool manufacturer in the United Kingdom to have a torque laboratory accredited by the governmental, third party body ‘NAMAS’ (National Measurement Accreditation Service). In 1995 the non-profit distributing private company UKAS or United Kingdom Accreditation Service was formed and took over this accreditation role. Norbar’s laboratory, number 0256, has an accredited calibration scope from 0.005 Nּm to 108,500 Nּm. We recently blogged on our calibration laboratory here.

Since 1996 Norbar has been establishing overseas offices for the purpose of product distribution and service. Norbar Torque Tools Pty. Ltd in Australia was the first and was then followed by the United States, New Zealand, Singapore and China. On 1 January 2012, Norbar’s wholly owned trading and service company opened for business in Mumbai, India. The companies in Australia, USA, Singapore and China each have a calibration laboratory with a similar scope of ability to the UKAS accredited laboratory in the United Kingdom. Each of these laboratories has accreditation by a local third party body; NATA in the case of Australia, NVLAP for USA, SAC-SINGLAS for Singapore and TAF for China.

And this concludes our potted history so far, the rest they say is history.

By Neil Brodey, Managing Director of Norbar Torque

DO TORQUE WRENCHES NEED TO BE WOUND BACK TO ZERO AFTER USE?

Anyone working in torque will have been taught to wind their torque wrench back to zero after every use.

Certainly, if the wrench is wound back at all it should not be adjusted below the minimum scale marking (usually 20% of maximum) – never to zero as this can adversely affect the calibration of the wrench. Beyond that, our position on this topic has been that it really depends on the application. We have thousands of Production Type wrenches in service that are left at their setting for months on end without a problem. Whilst the occasional user should adjust back to the minimum scale setting after use, if you use the wrench in an environment such as a commercial garage, the choice is yours. Either way is acceptable.

However, to test the position we have taken on the winding back question, we carried out tests over the past month. While we have not tested enough wrenches for this to be conclusive proof, the results provide some interesting insight into the debate. The test was designed to show the effects of leaving a torque wrench wound up at 100% of full scale against one wound down to 20% of full scale.

Firstly, four wrenches were taken from our production line and our calibration lab took results. Two wrenches were then left wound up to maximum and two wound down to their minimum scale setting. After 24 hours the calibration lab took further results, and again after a week, then again after one month.

The most significant result from the test is that all of the wrenches remained within tolerance, regardless of whether they were left at the minimum scale setting or at their maximum. The wrenches left wound to maximum did move more but the change happened quickly, within 24 hours, and then they stabilised.

We acknowledge that we took a small sample and the result almost poses more questions than it answers. For example, what happens to the same wrenches in 6 months and twelve months? How does a Norbar wrench compare with our competitors in this regard? These are tests that we will do and, no doubt, we will be returning to this subject.

For now, the test has not changed our view and our advice is this. If it is convenient to wind your torque wrench back to its minimum scale setting then you should do so but never wind it below the minimum marking on the scale. If winding back is inconvenient because you are using the wrench very frequently, then this will not damage your Norbar wrench. Other factors in the way that torque wrenches are used and sometimes abused will have a far greater influence on calibration and the final torque delivered to the fastener than whether the wrench is left ‘wound up’.

If you want to continue the discussion further, don’t hesitate to comment below or tweet us here and join us on Facebook here, and we’ll talk torque!

By Philip Brodey, Sales and Marketing Director

TOUR DE TORQUE – TORQUE CONTROL FOR HIGH PERFORMANCE BIKES

The importance of setting the correct torque when assembling equipment cannot be overemphasised. If you need an example of how important it is to set torque at precision accuracy, you actually need look no further than the common bicycle.

Old ‘bedstead’ bikes were generally easy and quite inexpensive to fix and an over torqued bolt might result in a stripped thread, simply requiring a trip down to the local bike shop or ironmonger.

However, those days are long gone and cheap and easy maintenance is a thing of the past because a revolution has taken place in the materials used in cycle manufacture. Heavy steel frames and components have been replaced by aluminium, carbon fibre, titanium and ultra-thin section steel tubing.

Bikes that are as light as those currently ridden in the Tour de France, such as one of Mark Cavendish’s specialised Venge bikes, are now within reach of amateur racers and keen leisure cyclists – note the next cyclist you see when stopped at a set of traffic lights.

Today’s bikes have the required torque stamped on their critical components. Clamping down too hard on carbon bars will crack them but insufficient tension in the bolts may result in the bars moving in the clamp. A torque wrench is becoming an essential component in the cyclist’s maintenance kit! Long gone are the days of the Penny Farthing – the correct application of torque is vital to engineering performance when it comes to bicycles.

At Norbar we demand the same consistent levels of quality and accuracy when manufacturing a 200 Nּm Norbar torque wrench as we do in the production of more specialised equipment. All of our tools are designed and manufactured in house and supplied with traceable calibration certificates. Accuracy and traceability help us to ensure that internationally recognised standards of quality and reliability are maintained for equipment used worldwide and across every industry sector – whether on a deep sea pipeline or a Trek Madone 6 Series.

By Philip Brodey, Sales and Marketing Director

Norbar Torque

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NORBAR: A POTTED HISTORY (PART 2)

DO TORQUE WRENCHES NEED TO BE WOUND BACK TO ZERO AFTER USE?

TOUR DE TORQUE – TORQUE CONTROL FOR HIGH PERFORMANCE BIKES

Norbar Torque

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Tag » Calibration

NORBAR: A POTTED HISTORY (PART 2)

DO TORQUE WRENCHES NEED TO BE WOUND BACK TO ZERO AFTER USE?

TOUR DE TORQUE – TORQUE CONTROL FOR HIGH PERFORMANCE BIKES