Madeleine trumped by Ruby Loftus

Trefolex and Tufnol ride again in Mechanical Engineering 101.

Famously, the hero of Marcel Proust’s multi-volume novel, “A la Recherche du Temps Perdu”, found that memories of a period many years before were triggered by a smell and taste of tea and a dipped madeleine.

Immediately the old gray house on the street ….. rose up … and the entire town, with its people and houses, gardens, church, and surroundings, taking shape and solidity, sprang into being”

Risking the bathetic after such a graceful idea and prose, The Lad found the opposite the other day: smells from his youth were triggered by this striking picture. It had been featured in a recent exhibition, Women War Artists (now closed), at the Imperial War Museum, London – website .

Reduced Ruby
IWM2850 Dame Laura Knight - 'Ruby Loftus screwing a Breech-ring'. 1943, Oil on canvas


Instantly, the workshop with its high roof appeared; it’s the Fifties. Machine tools are ranked in bays each controlled now by an apprentice in a white boiler suit. Each bay patrolled by its white coated Instructor. There was the low rumbling of the milling machines, the hum of the lathes just like the one in the picture, the hiss of the grinding machines. Equally pervasive was the smell of cutting oil and often the raw, burning smell of machined Tufnol – a composite material of linen and resin – still going It seems, [ ].

But if it is a really vile smell you are after then it is in the fitting bay in the corner of the machine shop. Here are the benches and vices where there was hammering and a continuous swish of filing. There, on the bench were the pots of Trefolex, a thread-tapping paste, green coloured and with a vile stench. You can still get it today [ ] though they may have got rid of the smell by now.

The Training School entertained both Trade Apprentices and Technical Apprentices. The Trade Apprentices were being aimed at careers as skilled machinists; whereas the Technical Apprentices were intended for the draughtsman’s career. Notice the suffix ‘man’. No women or girls then in the Fifties: they were all long gone after the Second World War. Not even an office girl. “Disturb the youths, you know”.

But, contrary to the popular vision, the Training School does not represent the milieu of the professional engineer. It is Mechanical Engineering 101 where, then, he or nowadays often she discovers the basics before moving on. The mechanicals move on to design or work on new products for the machines to make, the production guys to introduce better machine tools or ways of dealing with difficult materials.

It was here, in the Training School, that The Lad first tried cutting an external screw thread on a lathe with a single point tool. He found it difficult while the Trade Apprentices seemed always only to thrive on the challenge. Then they moved on to using the same technique to cut an internal thread. This is what Ruby Loftus in the picture is doing: under intense pressure in War time using the high skill of cutting what would be a buttress thread for a breech block of an artillery piece.

This magnificent picture though is much more interesting than just for the memories of The Lad. The picture is, most importantly, but also so powerful, painted in 1943 the middle of the War, shows only a one male, a single small figure in the distant background. The thunder on the Home Front had changed everything. The painting of this picture shows that the changes were so radical that they had to be recorded. It was a peak in women’s employment never reached again even today. However, almost 70 years later, girls and women do take their proper place as apprentices and professional engineers.

The dignity of Ruby and her concentration on the complex machine and work piece stands four-square with the haughty gaze of Henry VIII in Holbein’s painting.  The painter was Dame Laura Knight who had, pre-war, specialised in painting dancers and circus performers. . Though less important, The Lad believes this powerful painting is also the most accurate, realistic canvas of a rare subject – a snippet of Production Engineering. Unless, that is, someone else knows better.

There is the contained poise and tension of the lean of Ruby. It is that of a dancer yet with stillness. Countering the figure of Ruby and closely observed, are the dark, gleaming masses of the lathe: the tool post, the carriage and the tail stock. The tools are there too: a scraper to remove burrs, an internal calliper for measurement, parting–off tools and tool holders and a ring spanner for the bolts on the carriage.

Ruby is gazing intently at the spot lit tool. It is cutting the thread inside the breech ring during the very brief period as the tool passes from the side of the work piece nearest her out of the side within the rotating chuck. Her hands are not just supporting her but a part of her vital control of the machine. She rests the fingers of her left hand on the tool post to check and confirm the faint, continuous, humming vibration showing that all is well with the single point cutting tool. Her right hand performs the same check on the gearbox driving the feed screw and confirms that the carriage is moving. That same right hand was also well placed to switch off the drive to carriage and work piece in an instant when it left the inside surface of the work piece before reversing it back out in the same helical groove of the buttress thread but with a slightly deeper cut.

Now, in the Twenty First Century, a CNC Turning centre does it all more quickly, just as accurately but with less involvement of a human operator – male or female.


Engineering is one of the three drivers in the advancement of the human race. This blog aims to give to career seekers and also to the general public a taste of how this might be so. They are not well served by the current media. It is an engineer posting: not a ‘scientist’. It describes real professional engineering as it is in the real world usually in the present and occasionally as it was in the recent past.

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