Contamination is one of the most common causes of bearing failure and the cause is generally straightforward: the presence of foreign objects inside the bearing. In most cases, contamination will leave visible surface marks such as pitting, scoring or scratches. However, users should not assume that there is no contamination based purely on a visual inspection, especially if the operating environment is one where fine mists of fluids or superfine dust particles may be present. We can advise on initial bearing selection to protect from contaminants in the first place, and we can provide testing as required to ensure long service life. Failure prevention is far cheaper than replacement.

Brinelling is damage to the bearing raceway. It is most commonly caused by incorrect installation or incorrect replacement of a bearing, sometimes when a thrust force has been applied either deliberately or inadvertently. Generally, brinelling can be recognised by tiny indentations on the shoulder of the race which correspond to the location of the balls. Users should beware that one direct cause of brinelling can be hammer blows to the bearing, or a shock load exerted on a static shaft. We can advise on ways to identify potential causes of brinelling on your project and help you manage them out of the equation.

Since the experiment, no media outlet has managed to track down Mr A B, but if he were alive today he would be a relatively skinny 78-year-old who holds the record for the longest fast ever recorded.

Potassium is an electrolyte that is crucial to the proper working of the heart, as it helps the muscle tissue surrounding the heart to contract properly. Without it, Mr A B would have certainly died of heart failure, as his body would eat into the muscle tissue that kept his blood pumping.

For those of you wondering at home – and I know some of you would ask – Mr A B defecated extremely infrequently during his fast, popping off to the loo just once every 50 days or so.

Thanks to his insistence on fasting, and regular medical check-ups, he was able to achieve what no experiment could ethically test. He proved that if you were heavy enough, the human body could survive off its own body fat for extended periods of time (albeit with strict medical supervision).

By examining the wear path pattern in a bearing that has been removed from service, it is possible to obtain an idea of the conditions under which the bearing has been operated. By recognising the difference between normal and abnormal wear on the pathway we can ascertain whether or not the bearing has been used properly

Although he did not eat any food, he frequently drank water, and for the first 10 months of his total starvation, the researchers gave him yeast and multivitamins every day to prevent critical nutrient deficiencies from killing him.

Preventing failure could see a reputation preserved, lives saved, or simply the avoidance of inconvenience and unnecessary cost. It may sometimes be all of these things at once, so understanding the causes of failure and taking sensible preventative steps should always be regarded as vital.

Incredibly, when researchers checked back with Mr A B five years after the conclusion of the experiment, he had only regained 7 kilograms, and had no ill effects from the entire year he went without food.

In a static bearing, damage to bearing rings which is caused by vibration is what causes damage known as false brinelling. It can be caused by the machine in which the bearing is installed, and sometimes it can also be caused during the transportation of the equipment itself. Users should watch out for indentations on the axial and circumferential parts of the raceways. It may appear very similar to brinelling, but false brinelling is readily characterised by the degradation of the material as a result of a combination of both mechanical and chemical action.

Whilst variables will always apply due to the presence of different application and immediate environment values, the history of the bearing is “written” in the metallurgy.

But there was only one problem. No scientific journal or university in the world – even in the mid-1960s – could ethically allow their researchers to purposely starve a person for as long as possible.

"The average non-obese 70-kilogram male carries about 8,000 kilojoules of energy in glycogen, and about 400,000 kilojoules in his body fat," wrote Kruszelnicki.

At the 100-day mark, or roughly 15 weeks, the doctors noticed that his potassium levels were reaching near-critical lows, and consequently supplemented his yeast and multivitamins with a potassium supplement.

After an astonishing 382 days – or one year and 17 days – Mr A B had reduced his bodyweight from 207 kilograms to just 82 kilograms, a massive loss of 125 kilograms.

Despite this man weighing an enormous 207 kilograms, the staff at the hospital advised deeply against total starvation (for rather obvious reasons). But the man persisted, saying he was going to starve himself anyway, and that they may as well monitor his health along the way.

Dr Karl Kruszelnicki, on his blog Great Moments in Science, theorised that the average male could live off his body fat alone for a couple of days (if you really, really had to).

For the first seven days of his fast, he lived in the infirmary, surviving off nothing but water and multivitamins. After seven days he was sent home to consume food, but he carried on fasting in his own apartment, only coming in to the hospital regularly to have his carbohydrate metabolism, blood glucose levels and blood pressure levels checked.

Almost all of Mr A B's daily energy requirements were taken from his vast fat stores which, as it turns out, even relatively lean people can survive on for extended periods.

Carter Manufacturing LtdUnit 7 Isis Court, Wyndyke Furlong Abingdon Business Park Abingdon, Oxford United Kingdom, OX14 1DZ

Unsurprisingly, there are many ways in which a bearing cage can sustain damage, but amongst the most common causes are excessive wear, lack of lubrication, excessive vibration and overspeeding. If you have experienced cage damage previously then talk to us, we can usually isolate the cause and recommend the most efficient remedy.

Irrespective of whether it is caused by adjacent component failure or simply the build-up of static, electric arc erosion occurs when a current passes through a bearing and is broken at the contact point between the races and rolling elements. In turn, this can result in high temperatures at localised parts of the bearing which can result in surface pitting on the contacting faces. We can advise on how to avoid this occurring in your project.

Here at Coach, we come across some pretty extreme diet routines on a weekly basis. But nothing – and I mean nothing – comes close to an unnamed Scottish man in 1965 who lost weight by surviving off nothing but his own body fat for over a year.

If one side of a bearing is not properly aligned in relation to the other, the path of the balls or rollers will run from one side of the race to the other, and it will do this around one half of the circumference on the non-rotating surface. The rotating ring will also most likely have a wide roller path, which can often result in frictional forces producing a temperature high enough to either disrupt the efficiency or destroy the lubricant.

That was until 1965, when in the middle of a Scottish summer a morbidly obese man walked into the Royal Infirmary in Dundee and told the doctors he was going to starve himself to lose weight.

The origins of this epic fast are as curious as the story itself. Since the end of World War II, and faced with incredible numbers of starving people in Europe, the scientific community became engrossed in discovering just how much, or how little, food someone could eat before negative effects were felt.

Instead, the man was referred to as "Mr A B", and at just 27 years old, was far younger than any other patient who had come to the infirmary suffering from morbid obesity.

Just two tablespoons of nutritional yeast provides a person with 60 calories, 5 grams of carbohydrates and 9 grams of protein – including all nine amino acids, which the human body cannot produce on its own.

At Carter, we draw on many years of experience as a “go to” source for bearing failure analysis across the widest range of critical applications. Some of our customers are in industry, some build and maintain commercial airframes and powerplants, and some operate in the defence, nuclear, space or cryogenics industries. When a bearing failure occurs, they know to reach out to Carter to determine the problem and provide a detailed report with meaningful steps forward for future prevention. We can assist by providing users with the expertise and knowledge of failure modes, and we also have the testing facilities and equipment to ensure that users avoid the inconvenience, unnecessary cost (or worse) that bearing failure can cause.

This type of failure evidenced by a flaking of the raceway.  In short, fatigue failure is a result of a weakening in the grain of the bearing steel. It usually starts invisibly to the eye beneath the surface and then migrates to the raceway. This may be normal near to the end of the life of a bearing but it can occur quite readily at any point in its life as a result of excessive loads being applied. We can assist at the design stage to help you be sure to specify bearings that are truly up to the projected static and dynamic loads expected, and thus help prevent fatigue failure from ever occurring.

Proper lubrication is vital to bearing life. If a visual inspection shows any change in the colour of the grease, or if it smells burnt, it indicates a potential lubrication failure which will lead to a failure of the bearing. If a Lithium-based grease has been used, the surface may become brittle and can shine like a varnish: tapping it with a sharp instrument may shatter it. If the bearing is running in an oil bath and insufficient fluid is reaching the races, they may be dry to the touch and possibly ‘blued’. Any of these signs warrant detailed examination immediately.

Although the entire experiment was documented, analysed and monitored by researchers (and consequently published in a ground-breaking research paper), thanks to doctor-patient confidentiality (and personal preference) the man was never named, and no ID photographs were ever taken.

The reason doctors administered yeast is simple – it was his only source of protein, and without it, the body starts eating its own muscle tissue. Without any form of protein at all, the man would not be able to "direct" his body to consume his vast amounts of body fat as fuel, and would die within weeks.

(It must be noted, however, that the research published in the Postgraduate Medical Journal focused purely on the physiological effects of his fast, and not the way it changed his psychological connection to food – which must have been substantial.)