How were words and numbers printed onto old instrument panels?

Some dials for aircraft had the numbers etc painted by hand with RADIUM paint to make them luminous.

This was done (usually) by women using kid's water colour brushes, which they licked to sharpen up the tip.

It is arguably the cause of the biggest occurrence of radiation induced cancers in the UK. I have seen photographs of the affected tongues and nearly lost my lunch.

More recently, radiation surveys at Dalgety Bay, Fife, which were looking for signs of "leakage" from sub overhaul work at Rosyth found radioactive particles on the foreshore - these were the remains of dials from aircraft scrapped from the former Royal Navy aerodrome at Donibristle.

The last proposal that I heard was to re-landscape the eroded foreshore and put up a notice advising people not to eat the sand. I am not a Health Physicist, but I think the danger from dog dirt on the beach is greater.

Dick

p.s. The same? Paint was used for the same purpose in the Westclox alarm clocks we all had before electronic clocks were available. They all went in landfill when worn out.

Around 1980 I was a Tool Designer - mostly machining jigs, assembly fixtures and press tools - in a teleprinter factory.

Most identification plates and some laminated labels were done on a Taylor-Hobson pantograph machine which rotary-engraved characters an logos from a scaled-up master. Dunno how the latter was made but suspect spark-eroder or mechanical diesinker.

Letters and special characters on key buttons were 'hobbed' - hugely different from the same-named gearcutting procedure - by injection gang-moulding sprues of the characters in higher-melting point plastics, then mounting these in parent moulds and moulding the keybuttons around them in contrasting coloured lower-melting point materials.

Later, working in an aircraft parts manufacturer, there was a specific craftsman kept on well past normal retirement age because he could paint tiny serial numbers on the rims of multiway connector casings for missile wiring looms. These were then varnished over the top, and it was evident from some traceability enquiries that they could survive the use of said missiles.

It used to amaze me that the man's hand might tremble holding a cuppa or a sandwich, but he could paint his numbers in characters a couple of millimetres high with almost printlike precision on a spherical-radiused surface!

Teaching at a large College the first and second generations of computers for student use were IBM machines. The keyboards on these were clattery devices where the key tops were made like this - basically like sticks of rock where the black letter went right the way through.

It was the custom when these became dirty for the technician to wipe them over with alcohol and they came up a treat!

When Amstrad PCs came out at a far more reasonable price these were bought in quantity and everything was fine until the first one became dirty. The keyboards on these machines had silk screened letters and with a couple of wipes of the alcohol the letters disappeared leaving a clean and fully working keyboard where all the keys were blank!

At a mechanical controls company I worked in in the late '70s, logos and symbols were heat-stamp printed in white on pull-knobs for bonnet-releases, valve lifters and suchlike. It was cheap, tacky, and it looked it.

Back in the 1970s I worked for a contract company called Waverley Electronics (later bought by Ultra) in Weymouth, handling a lot of Royal Navy equipment, developing and selling its own-design sidescan-sonar (for sea-bed mapping) and building wardrobe-sized 'Vero" rack cabinets of monitoring instruments for the giant floating cranes in the burgeoning North Sea oil industry. These informed the crane-driver of the immediate wind and wave conditions.

Most of the labelling we needed do was on a Rank-Taylor-Hobson pantograph engraver, and I was one of its operators for a time. This was used not only for lettering but also cutting out the specially-shaped holes in aluminium panels for 'D' and other form connectors. That entailed a roller follower round a scaled-up, bas-relief "negative" of the hole, fabricated from aluminium plates. Drilled holes in the pattern gave the screw-hole centres to "engrave" through the work-piece.

The side-scan control panels were of stainless-steel. I forget if we used carbide or HSS steel cutters to engrave them; or if in fact we had them screen-printed.

We used thick enamel paints for filling the letters, applied with a strip of stiff card.

The worst material I engraved was some sort of rigid plastic. I have no idea what it was but it emitted a colourless fume with a faint, sweetish smell, and although in small volume, giving me a very unpleasant choking sensation.

The oddest task though was to cut two very fine slots in a piece of bronze strip for another piece to lock into, like the familiar assembly method on tinplate ware. After much head-scratching in the metalwork shop I said I'll try engraving it. It worked, using a cutter ground to a much finer than normal point on the proper engraving-tool grinder, and with a bit of experimenting on an off-cut.

'

The oil-trade work, and some other items, were finished for us by a contract painter who also screen-printed the labels on the gloss magnolia; to, so specified the drawing, "Exhibition Standard". Would have gladdened the heart of the most meticulous judge at "The Fosse" , they would!

'

We encountered the edge-lit displays on a piece of RN equipment we overhauled. These were if I recall, "Test Set, ASDIC" units; built so all the bits dangled inside from an inner lid of a pressed-steel and welded box built like a concrete khasi. As one of the inspectors told me, these things have to be not only storm and shell-shock proof, but also Jolly Jack Tar proof.

The meters and switch labels were below a thick acrylic sheet with bevelled-edge cut-outs milled around the outlines of the parts to be lit; and illumination was from low-voltage lamps at various points around the sheet.

''''

Who mentioned 'Letraset' a while back? I think Waverley Electronics' drawing-office did use it from time to time.

I made extensive use of it at home, when for four years, I was Wessex Cave Club Journal Editor, and the last to use a mechanical typewriter before I handed over to the first of the computer-wizards.

My predecessor had used ordinary draughting stencils for headings etc; and the result is tidy but a bit spindly and bland.

I used a lot of literal cut-and-paste, from photocopies of 'Letraset' master-sheets of the magazine's various section headings, plus the same transfers for making up the unique article headlines. A framing template from acrylic sheet, type-setting rule and blue pencil completed the formatiing tools. (Yes, really a blue pencil. Used lightly, the faint markings do not show on the printer-shops' litho-plates.)

I enjoyed doing it - it was certainly creative!

...

Though another digression I will mention one Waverley Electronics unique task which the edge-lit displays reminded me we did. It was among some 'WE' work for the CEGB laboratories at Marchwood; and was an instrument to photograph random, very short, infrequent transients, in some system I know not of what.

The heart of it was a camera aimed at an oscilloscope screen, triggered by the transient, via a control circuit.

To enable accurate focussing and contrast to sufficient detail while excluding external light, the instrument included a "light funnel" linking the screen to the much smaller camera lens. It was a sheet-brass funnel of rectangular section of appropriate dimensions, internally silvered if I remember rightly. Within this, in full contact all round, was a polished, acrylic pyramid-frustrum that was the light-guide itself.

I never saw it in operation, but I understand it worked perfectly!

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