Sunday, December 30, 2018

Was that an American Caligraph 2 typewriter?

In a light and (then) slightly risqué comedy film, released in 1933, one of the main characters is a playwright who uses a typewriter. Perhaps to illustrate the unconventional, bohemian atmosphere he's not using a 'normal', contemporary machine, but an ancient upstrike typewriter.

Not to give away too much of the plot, but she did not keep things oiled as promised while he was away. The keys are rusty and the shift is broken, complains he. (But the bell still rings!)

This typewriter even gets a good close-up.

The machine doesn't have any recognisable decals, but it looks a lot like an American Caligraph 2 that would probably date from the 1880s. Even back then this would have been a fifty year old typewriter. Decidedly quaint looking, both for today and for a 1933 viewer.

So a small factual error; as can be seen from the impressive amount of keys, this is a full keyboard typewriter - so would not have a shift.

But then, the comments are metaphorical - the typewriter being a prop. This is after all a 'pre-code' film and one by Lubitsch at that :)

Thursday, December 27, 2018

The 1920s Electrical Outfit (reproduced)

An electric accessory outfit for use with a Meccano set was introduced in 1920 by Meccano - to introduce to boys the miracle of electricity.

The included manual explains that electricity plays a tremendous part in every-day life as "the wonderful power" that enables such things as electric light, electric trains, telephone and telegraph. It goes on to explain that even though "no one yet has been able to define it or tell just what it is", it is an amazing natural force "capable of unlimited uses".

The original 1920s Electrical Outfits were quite expensive back then, and are rare and expensive today still. So to experience today a bit of this wonder of 1920s advanced technology, a reproduction set was made. Complete with a reproduction box, manual and parts (the printing codes having been altered to clearly state it is a reproduction). The very informative primer at the NZMeccano galleries provided enough information to enable a decent repro to be made.

The parts are quite simple, but still opened up the then new world of electricity. Still have to complete the set with correct-pattern wooden spools and some cotton-covered wire, but already something can be built with it. The parts being new, there are no issues with them being rare or fragile.

Browsing the January (1928) issue of the Meccano Magazine, there's an article with an improved design coil-winder.

Using Meccano from the same era this was put together; winding a little coil on bobbin (part 301) using some lacquered magnet wire.

Not paying too much attention to the amount of turns, but just made sure that the overall resistance was not too low - the coil turned out at approximately 8 Ohms, so should be fine with a battery and also fine with a USB power-bank.

With the soft-iron pole-piece (part 308) it makes a good electric-magnet, with a short rod it's a working solenoid.

The model No. 8 in the instruction booklet is a combination of a buzzer and a tapper-key to create a small morse telegraph setup. All workings can be seen and understood - and it works too!

The buzzer can be tuned with the contact-screws and the moving strip. In this case a bit of extra weight was added at the end to lower the buzzing-frequency. The corroding effect of the making-breaking of contact does illustrate the usefulness of the special silver-tipped contact-screws part 307 - still have to create some of those.

Still to add some parts such as the cotton-covered wire and correct pattern nuts. Hex-nuts still used here, square nuts have been sourced and are on their way. More parts to follow :-)

Hands-on very basic electrics, but even something as mundane as an electric doorbell buzzer once was new and the very height of technology.

Friday, December 21, 2018

High impedance vintage headphones

Venturing into a new domain with 2000 Ohm resistance per phone.

Something new to discover in the area of vintage 20th century technology. These headphones date from the 1920s - with their very high impedance of 4000 Ohm in total they're meant to be used with a radio of the period. Most likely a crystal wireless set, or perhaps even an early (expensive!) valve radio.

This particular set of headphones survived what are probably decades of disuse in good shape with the nice leather-covered headband fine too. The metal parts clean up nicely, with the odd bend gently worked out.  The earcups are probably not bakelite, but hard rubber. Molded on the inside is the Ericsson wordmark - so these are Ericsson headphones (or at least a make that used phone speakers made by Ericsson).

Nevertheless when they arrived, the phones were broken. This is easily tested by tapping the leads on a battery - the DC pop and crackle of even a 1.5V AA cell will be clearly audible. These headphones however remained completely silent. Open circuit somewhere.

From a browse-around on the web, it becomes clear that these can often have some broken connections - generally where different gauges wire have been spliced together. Also from that browse-around, some instances where the insides get replaced by modern (cheap) drivers - sometimes not even soldered in place, but a gash sawed in the cups (<gasp>!) to get the wire through. What also is clear from some reading up, is that this type of headphones can usually be repaired - like much of the technology of the period, it should last.

Internally, the headphones have four 1000 Ohm coils all in series. By unscrewing the earcups - these come off easily - the iron diaphragms with their gasket-ring come off to give access to the inside. Methodically measuring the resistance from point-to-point, the defective coil was easily identified. Undoing the screws that hold the assembly of coils and magnet in the aluminium cup, the set of coils with the defective one was taken out for closer inspection. Clipped together to not break the connection between the pair, the paper wrapper can be gently peeled off.

Unfortunately, the start and end lead-wires were both still fine and correct - so the break must be inside the coil. (Thought it odd that, with 4 kOhm I should think that not even hooking them up to the mains could damage a coil...)

Then to proceed to look inside the coil, nothing else to do but to unwind it. With a quickly rigged-up little coil-winding tool - to not get all tangled up in the very thin lacquered magnet-wire - unwinding begins. (Coil winder made with Meccano of the same vintage - sort of a 'mechanical breadboarding' toolkit.)

Luckily after only a few meters of unwinding, another paper-tape starts to appear. The wire for this coil was apparently spliced halfway winding. Probably during manufacture, when one spool ran out and another was placed onto the machine.

When gently peeling off this paper tape, the wire-end just fell out. This very likely was the original break - some checking up with the multi-meter confirmed that the rest of the coil-windings were fine.

Gentle rub with fine-grit sandpaper to remove the lacquer, then twist the ends together. To make sure, a small drop of solder to keep it all tight, then a new paper (masking) tape to hold the connection safe. The paper-tape holding the new splice is then wrapped around the coil and the rest is re-wound too. The thicker lead-wire is spliced on in the same manner, wrapped around and held in place with a small extra bit of paper-tape. And thus a fixed coil. A little spot of paper-glue and the original wrapper is placed back too.


The lead-wires are then soldered back onto the eyelets that are screwed to the terminals in the cup and the whole assembly comes together again in its aluminium cup.

Carefully placing back the diaphragms (with gaskets) and screwing the earcups back on, the headphones then simply snap back into the forks of the headband. Making again a complete 1920s set of headphones that are now functioning fine.

These should last for decades yet - now for a crystal wireless set :-)

In the meantime; with a quick soldering of some sockets onto a 3.5mm jack the headphones can already be used with any modern music-player or phone. With the very high impedance of the headphones, the volume must of course be set high for a decent, still modest sound volume. The sound is a bit 'tinny' perhaps, but it does a very good job of reproducing the period music - voice comes through very crisp and clear. Also despite being relatively heavy and with hard earcups, they're not as uncomfortable as you'd perhaps expect.

So not quite modern 'hi-fi', but surprisingly good headphones from the 1920s.

Tuesday, December 18, 2018

Fewer damaged cases through more manuals

The increasing availability of typewriter user manuals must surely help with the preservation and use of the machines. Over the past year or so, there were a few online listings that illustrated I think a small example benefit for especially the Remington portable typewriters of the 1920s.

Over the past decades, these have mostly lost their instruction booklet and the knowledge on how to lock the carriage has been forgotten. So when the machine was 'played with', the knob would not have been pushed back into the carriage to lock the carriage and the machine would not quite fit in the case. The net-effect is usually a damaged case (distorted, scratched).

Over the last year however, a few online listings explicitly mentioned the instructions - and how the machine fits inside the case. A few, like the example July listing shown, included one or more pages printed from the scanned user manual that's available online.

So in addition to the odd 'services' that'll sell print-outs of freely available manuals, the digital files are probably being found by more and more people. And more manuals online -> better kept typewriters (again sold with instructions).  Good show, that :-)

Friday, December 7, 2018

Torn pages in the instruction manual (fixating)

Old manuals can have torn pages. All older paperwork of course can be damaged, but especially instruction manuals will be prone to tears in the pages. Also (folded) leaflets that come with machines often have damage.

A while ago I purchased this instruction manual 'Book 1' from 1924. This is over 200 pages, so a good thing that it was bound, instead of still the standard stapled booklet.

This book of models was always used very carefully. It must have been, to have survived this long in this fine condition. Nevertheless, a lot of its pages had tears - some smaller, some larger. As example, the small tear in page 115.

As the book is intended to be used again with a Meccano set of similar vintage, these tears should be stopped from becoming larger.

To fixate these tears, a very small amount of PVA glue was used. This is excellent for glueing slightly porous materials and it will not adhere to smooth, closed surfaces. As the surface to be fixed again is minute, an equally small amount of glue must be used - otherwise the moisture from the glue will wrinkle and damage the paper. Also, because it is so small a strip of glued material the extra local stiffness does not hinder the page.

Before applying with the finger or a toothpick a diminutive strip of glue, a plastic binder is slipped under the page.

This will prevent other pages from getting any glue, and the PVA will not adhere to it. (I later found out that wax-paper is generally used for this.) When the tear has been 'closed' again properly (with the right side on top, tears are rarely vertical through the paper), then the binder is closed to cover the glued page. Then closing the book ensures everything is straight and flat. (Add extra weight if needed...)

Letting it harden for a few minutes, the book can then be re-opened and the plastic binder can be taken away. The tear is not quite invisible, but it is fixated and will not tear further.

Just about every other few pages a tear was fixated this way - making the book fine to use again. Lots of little mechanical 3-dimensional puzzles.

Like a little monoplane.

Or a potato-spinner.

Fun stuff, and the instruction manual now again good to go for several more decades!