How were words and numbers printed onto old instrument panels?

[Simon Robinson 4Participant @simonrobinson4]

Before laser etching how would words and figures be printed onto instrument panels and dial faces like on vintage aircraft like spitfires or the cabs of old locomotives etc? They look like they are engraved into the metal or plastic but how?

[Simon Robinson 4Participant @simonrobinson4]

[bernard towersParticipant @bernardtowers37738]

The instruments I deal with (speedos and rev counters) are screen printed.

[Jeff DaymanParticipant @jeffdayman43397]

I worked early in my career at a huge US controls firm's Canadian branch plant, early 1980's. There was a department there that engraved then paint-wiped all manner of panels and tags. They made such engraving and paint wiped plates for industrial controls, valve products of all kinds, and military cockpit panels. One day I was in the department they were making a small replacement instrument panel section for the CF-100 aircraft. There were still some in service at that time with the RCAF and I was told this particular panel got abraded by a hose or pilot clothing over time, and periodically needed replacing.

Anyway, they used a manual pantograph type engraver with V shaped D bit engraving bits. There were storage cabinets with dozens of sets of guide lettering typeface blocks of different fonts and sizes. The main technician for the department was a lady called Doris, who had been doing the job for over 30 years at the time. She was very fast on all aspects of the work, and I expect she could give a CNC engraver a run for its' money in a panel making race if she were alive and at her equipment today (but sadly both she and the equipment are long gone). The other member of the department was a gent Gordon who helped with the typeface setup, proofreading the typeface before engraving, and doing the mountain of QC paperwork for the military related work.

I got to know this department when they requested some specially ground engraving points to be designed and made. I got the assignment to design the changes on the points, make the CAD and drawings for them, and coordinate their manufacture with the toolroom. When completed I walked the points over to the department and watched as Doris tested one. It worked as hoped, and I enjoyed coffee with she and Gordon and had a great chat about panel making. One important secret they let me in on was that they used Ronson lighter fluid on a lint free rag to get a crisp clean one pass paint wipe-up. Good fun.

Edited By Jeff Dayman on 05/11/2022 23:48:31

[peak4Participant @peak4]

Pantograph engraving machines in some cases I'd imagine.
i.e. Taylor Hobson amongst others.
I can even remember Timpson making labels, on laminated plastics, using smaller versions in my youth.
I've still got some of the laminate, but no machine to engrave it.

Bill

[John Ockleshaw 1Participant @johnockleshaw1]

Hello Simon, Many clock and watch dials were and are pad printed

[NealebParticipant @nealeb]

What is pad printing?

[Tony Pratt 1Participant @tonypratt1]

Posted by Nealeb on 06/11/2022 07:55:59:

What is pad printing?

Try Google for more information than you will ever want🤔

Tony

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Nealeb, Wikipedia explains Pad Printing

Regards Nick.

[Jon LawesParticipant @jonlawes51698]

For custom gauges we used letraset or pantograph engraver.

[Peter Simpson 3Participant @petersimpson3]

I spent many hours as an ICI apprentice instrument technician engraving panel labels with the pantograph engraver. As above, one of pressure gauge were usually done with letraset.

[Clive FosterParticipant @clivefoster55965]

Jon

I've always been totally in awe of folk who can use letraset and get professional results.

My efforts tended to re-define the concept of mis-aligned and it was a cause for serious celebration if all the letters were still in place after a month or so!

Clive

[Martin KyteParticipant @martinkyte99762]

Generally engraved using a pantograph and the filled with coloured wax. We used to do our panels like that in the Lab and very nice they looked too. I still have some of the wax crayons in a drawer somewhere.

Letraset worked for a while after this for one offs and then we moved to large printed labels using a UV film system. That was eventually modified to be laser printed until it was withdrawn and we have just bought a label printer to cover our needs.

On a more commercial basis screen printed panels are good for volume production and has been mentioned pad printing which I have never seen but I guess must be a kind of offset lithography but using a flexible pad.

These days it is possible to ink jet print all sorts of stuff including strange surface shapes with the inkjet head on a robot arm. I think you can even do vans like this.

regards Martin

[Lee RogersParticipant @leerogers95060]

My aunt worked in the engraving shop at Handley Pages. My first watch ,a birthday present at the age of 10 was engraved on the back with my name and address. Factories in those days had many skilled people doing the small unglamorous jobs like engraving. That the pantographs were kept busy is in no doubt , just google a picture of the Victor cockpit.

[blowlampParticipant @blowlamp]

[DaggersParticipant @daggers]

One of my first jobs in the DO was creating all of the front panel artworks for most of the UK TVs. Names like Marconiphone, Ultra, Ferguson, DER, Radio Rentals etc. The artworks were created on Bristol Board using a combination of indian ink & Letraset at 4:1. These artworks were photographed in-house and silk screens with photo sensitive coating were exposed using the negative’s and panels screened using ink.

Happy days.

[Robert Atkinson 2Participant @robertatkinson2]

Instrument panels would be engraved or screen printed as previously discussed. For actual instruments that were made in quantity the dials were often stamped out of thin brass or light alloy. The depressions for the markings were made by the die and then paint filled. Sometimes this was combined with screen or pad printing for smaller print.

On electrical instruments Hewlett Packard used to use an automatic machine to make individually calibrated scales for meters see https://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1961-03.pdf

Robert G8RPI.

[Nicholas FarrParticipant @nicholasfarr14254]

Hi, a photo of a label made from plastic laminate that peak4 mentioned earlier, this one is 106 x 23mm & 3mm thick, and has five layers, two thin black layers on the front and back, two thicker white layers under the outer layers, and a black layer in the middle, which is the thickest. This was on a steel stop log from a river basin that five stop logs were refurbished in my final day job, the brown staining on the white edges being rust. These were probably done with a pantograph engraving machine.

The electrical department in my day job from many years ago had one of these pantograph engravers, which they made labels for the control panels etc. and also made our own name discs for our isolating locks, which were used when we did maintenance on machinery.

Regards Nick.

Edited By Nicholas Farr on 06/11/2022 14:53:40

[old martParticipant @oldmart]

Instrument panels were often made from clear Perspex or Plexiglass (acrylic) sheet about 1/4" thick. As well as the holes cut for the instruments and switches, they also had several round holes for lights which could shine through the thickness of the sheet. The sheet was painted both sides, commonly grey or black and then engraved about 1/4 to 1/3 the thickness deep on the front surface. The engraving was filled with translucent white paint so that when the lights were on the figures and letters were clearly visible in the dark.

Dials for instruments were also engraved and the older ones had the engraving filled with "tru lume" luminous paint (radium mixed with a phosphorescent paint), which is radioactive and dangerous to handle because it is degenerating to dust with age.

The replacement dials and hands for older instruments are engraved with flourescent paint in the engraving. If the instruments do not have internal lights, then UV backlighting in the cockpit is used.

Modern practice is more towards silk screen printing rather than engraving.

On the instrument panels I made for the Wessex Mk3 out of 6mm acrylic at the museum, I used Letraset white characters which look good from a distance, not noticable except to close examination.

Edited By old mart on 06/11/2022 15:27:14

[SillyOldDufferModerator @sillyoldduffer]

Go back far enough and it was all done by hand. But pantographs appeared early and the Victorians were a highly inventive crew, coming up with many different mechanical ways of producing neat art-work.

Apart from one-offs and specials, I think the last hand method in common use was applying luminous paint to compasses, clocks and dials intended to be seen in the dark after a power failure. The paint contained Radium and was extremely expensive – about £43,000 per ounce if it were legal today – and applied in tiny quantities by skilled workers.

Dodgy stuff! Before the Nanny State spoiled everything by making a silly fuss about irresponsible working methods just because loads of people suffered agonizing deaths, Radium dial painters suffered an Industrial disease due to professionally licking the brush to get an extra sharp point. The paint killed its inventor too, even though he only handled it.

About 1975 I remember the Royal Navy hurriedly withdrawing a manual telephone switchboard after discovering each socket and plug being marked with a large dab of radioactive paint made operating the thing more dangerous than breaking up old fuel rods at Windscale! Fortunately, exposures were low because it was only used for emergency damage control. I don't know if any sick sailors sued the government!

Dave

[Swarf, Mostly!Participant @swarfmostly]

Swing the lamps, lads!

In 1954, between leaving school and starting college, I had a holiday job at a firm that held a contract to refurbish an Army radar, AA3 Mk7, if I remember correctly. I was the only short term employee. The various units were removed from the caravan and our job was to perform any repairs found by the incoming inspection, perform any scheduled modificationa and clean up any field modifications, paint the upper surface of the chassis with grey paint, the undersides with oil and anoint all the cableforms with a mixture of something and carbon tet! All the steel chassis were cadmium plated. I've forgotten what the 'something' was, it might have been lanolin!

Each front panel control had its individual label, engraved on the material shown in Nick's post, it was called 'Traffolyte'. We had to refill the engraving with white wax, made temporarily soft by moistening with white spirit. The labels were refitted to the front panel using bifurcated aluminium rivets which could be a swine to set by hand!!

Best regards,

Swarf, Mostly!

[DiodeDickParticipant @diodedick]

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.

[Mick B1Participant @mickb1]

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!

[Nick Clarke 3Participant @nickclarke3]

Posted by Mick B1 on 07/11/2022 09:17:29:

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.

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!

[Mick B1Participant @mickb1]

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.

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