Monday, April 30, 2012

Mystery revealed: the Polt Silencer™

Here's the solution to the mystery in my previous post.

The object you see below is a quiet carriage return wire from my purple Torpedo. It was too loose, so it wasn't working; I took it out to inspect it before squeezing it a bit tighter so it would work again.



The principle is simple: the wire is looped around the escapement wheel; when you return the carriage, the rotation of the wheel (counterclockwise in this photo) pushes the straight arm of the wire against the dog (a tooth that engages the teeth of the wheel when you're typing). This gets the dog out of the way so that the wheel's teeth don't hit it.



I don't know when the first machine with a quiet carriage return was introduced, but in the '50s this became a frequent feature on typewriters of all sizes. With me it has become a bit of a fixation. Not only does this feature make the return quieter and smoother, but it simply seems mechanically more correct: you're not wearing down the escapement or doing unnecessary work.

Usually the sound of a typewriter that lacks this feature is a not-unpleasant "zzzzzip." In fact, many typists really enjoy the canonical end-of-line sounds: click clack click clack DING zzzzzzip. But Smith-Corona portables tend to make a nasty, rasping noise when you return the carriage. It adds a jarringly unrefined element to these generally sophisticated typewriters. I've often wished I could fix it, and after studying the Torpedo wire I decided to try adapting the principle to a Smith-Corona. I set to work with some spring wire, wire cutters, and needlenose pliers.

My first prototypes were too simple. They didn't grip the escapement wheel enough, or they were liable to be knocked out of place when the typewriter was operating. So I gradually developed a more complicated shape to account for these problems.



Here's my successful design. Meet the Polt Silencer™.



Here's what it looks like when installed. (It's designed for midsized Smith-Corona portables made from 1950 on, AKA the Super 5 line and later.) Getting it in is a bit tricky, because you have to slip it under the tabulator brake (a circular device with various springs which is attached to the escapement wheel). It works just like the device on the Torpedo: when you return the carriage, the escapement wheel turns counterclockwise and the Silencer pushes the dog out of the way, avoiding That Nasty Sound.



Does it make a difference? Judge for yourself.

Without the Silencer:



With the Silencer:




(Supermodel typewriter: Sterling Silver Surfer. Video by iPad.)

It's in the nature of the Smith-Corona design that it still offers more resistance and sound than extremely smooth machines such as Olympias, but the Silencer creates a definite improvement. It leaves me wondering why the company didn't add such a feature. In any case, I feel a great satisfaction in having actually invented a helpful typewriter part.

Will the Polt Silencer ever be available to the eager masses of Smith-Corona users? Possibly. There are wonderful machines that can be programmed to make custom wire forms. It would be so much fun to watch them produce my design!




30 comments:

  1. That is genius. Bravo, Richard Wan Kenobi!

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  2. That's quite a difference! Fallow Fields may have to license that...

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  3. (Sorry for the delete--it showed up in the wrong place.)

    So wait, that nasty bzzz noise is normal? My silent-super hasn't worked in so long that when I tried yet another hacked fix, it sounded so off that I didn't want to keep typing...

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    1. Every Smith-Corona from 1950 on that I find seems to make this unfortunate noise.

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    2. THis could be very helpful... I"d love a working SCSS again...

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    3. Would you allow a version to be made out here in the west by mine own hands in the quest of working typewriters and happiness?

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    4. Naturally! Everyone should feel free to imitate this idea, as my ™ is purely a joke.

      For perfect results, you may also want to bend the little tab that limits the movement of the dog (just before the left end of the line pointing to the dog in my diagram). It's a very firm little tab, but the tip of a small screwdriver can move it a little to the right to allow for more clearance.

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    5. I will have to try this... although I may be sending forth a video with the request of help if it doesn't work out... I really miss my silent super.

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  4. So, does the wire move to the left and the dog moves with it to disengage the escapement?

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    1. No, when you're returning the carriage the escapement wheel turns counterclockwise and the wire moves to the right.

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  5. This is great, Richard! You'll sell a million! I'll buy twelve! And no disassembly? You just slip it in place (albeit with difficulty)?

    == Michael Höhne

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    1. That's right, no disassembly is required.

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  6. Federal Law requires you to purchase a $450 tax stamp and pass an FBI background check in order to have a silencer on your weapon of choice. :D

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  7. Excellent fix! And nicely documented too. It was only when trying get my SM2 working recently that I took the trouble to peer into the escapement to see what's what. I can tell you came away with greater enlightenment than I!

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  8. How wonderfully home-brew. Before you know it you'll be creating typewriters out of twine and grit. Great job!

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  9. Smith Corona should have issued earplugs with every model 5. Is it too late for a recall to add your spring? Your next mission is to silence the typebars!

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  10. That's incredible. So, it makes you wonder if SC thought the noise was pleasantly endearing, or just didn't want to - ah - spring for the expense of that little wire thingummy.
    I'm not sure I'm ready to try this yet - I subscribe to the ain't-broke-don't-fix-it school of thought w/r/t machines. But doggone if you don't make it look simple.

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  11. This little device (the Polt Silencer) is a great example of why I like analog mechanical devices like manual typewriters, because such mechanical parts function as analog logic computers. That little bent wire functions like some sort of software would in a program:

    IF (CARRIAGE RETURN=YES) THEN (SLIDE DOG ASIDE) ELSE (LEAVE DOG AS IS)

    Anyway, great post, Richard.

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  12. I just think SC probably never thought to put a mechanism in there. Great work though!

    Hang on... is this the first engineered typewriter product in decades?

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  13. Hee Wack, Richard! My Super G sounds like a rusty crosscut saw hacking at a taut wire. Your engineering acumen has given me a new phrase: rubbing the dog the wrong way. Rob

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  14. Great work Richard.

    I will look for you on the Sharks when you start your spring factory.

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    1. The Sharks?
      Fallow Fields?
      Help me out here, folks, I am out of the loop.

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    2. It's a TV program where millionaires give people with good ideas to start a business money to do it.

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  15. Wondering if Fallow Fields might be the piece being played by what sounds like my countryman sax player Courtnay Pine... behind the spring fabrication tools.

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  16. Nicely done, sir! I love mechanically-oriented posts like this. Picked up some new terminology that I hadn't known before, learned something new about Smith-Coronas, and got to see your fine handiwork in action. I'll have to file this one away in the back of my brain.

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  17. what type and gauge wire was that? did you temper it at all? (and sorry to ressurect an ancient thread, but this is relevant to a similar pursuit of my own) thanks!

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    1. I was very unscientific about this. I didn't temper it, and unfortunately can't give you the characteristics of the wire. It was a length of wire intended for jewelry.

      Hope to hear about your own project sometime.

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