How were words and numbers printed onto old instrument panels?

[Nigel Graham 2Participant @nigelgraham2]

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!

.

[Author]

Posts