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History of Action Plastics?

  • 1.  History of Action Plastics?

    Posted 02-14-2013 19:52
    Was called to look at a Heintzman Elgin today, which contains plastic jacks and backchecks. These pieces are all crumbling with age, and would need to be replaced to make the instrument playable again (whether this should, and actually will happen, with the associated costs, is another question...)

    At any rate, I checked the date on the instrument; the serial number corresponds to a production date of 1949. I thought there might be a mistake, that plastics in piano actions would not have appeared that early. But after a quick search of past threads on this site, I found a few other references to instruments of similar vintages with plastic action parts.

    This makes me wonder, when were plastics first introduced into piano actions, and by whom? What sort of plastics (Bakelite? Nylon?) were initially used, and what makes today's plastics so much better than the early materials, which are now succumbing to the ravages of time?

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    Ian Gillis
    Chester Basin NS

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  • 2.  RE:History of Action Plastics?

    Posted 02-14-2013 21:28
    Ian, I don't have first hand knowledge of plastic dates, but my experience with them indicates they were popular from about 1949 to 1956.
    During the 70's and beyond I have heard reports that the crumbling was due to too much catalyst in the mix that caused the plastic to continue to harden long after its manufacture.  I can't imagine that today's material would suffer the same problem.

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    Thomas Gorley
    RPT
    Los Altos CA
    650-948-9522
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  • 3.  RE:History of Action Plastics?

    Posted 02-14-2013 21:30
    Ian,

    Here is an excerpt from Stay Tuned, The Plastic Piano - An Introduction by Bill Calhoun:
    "... Plastic has always been one of those new materials, ever since the industry started using celluloid in the 1870's.  The chemistry behind various plastics was not well understood then, and innovation relied on experimentation, sometimes with terrible results.  There were three prominent plastics disasters in piano manufacturing history.  The first was with PVC, used in the 1940's and 50's to make action parts.  Molded PVC parts were successful at first, but as the plastic aged, it tended to spontaneously disintegrate.  This effect would take several decades to manifest, so that left a lot of time to build plenty of pianos with PVC action parts, all falling apart now. ..."

    As to types of plastics used since day one, go to  The History of Plastics .


    Keith McGavern, RPT
    Shawnee, Oklahoma, USA
    tune-repair@allegiance.tv



  • 4.  RE:History of Action Plastics?

    Registered Piano Technician
    Posted 02-15-2013 18:18
    I wouldn't take Bill Calhoun as an expert, as there are several inaccuracies in his blog (eg, Kawai actually made plastic action parts at least in the early 80s, not just 90s, and the plastic jack Calhoun talks about was probably Yamaha's - which was and is "better" because it is lighter, and moves faster, so they say). Thus I am skeptical of his claim that the early piano plastic (as in the elbow and other parts that shatter) was PVC. It is possible he is correct, but I would want it on someone else's authority, and with some references. The explanation I have heard, for whatever form of plastic it is, said that the solvent that made it possible to mold the plastic, and gave it strength and some flexibility, evaporated over the years, leaving a brittle substance. Makes sense, but doesn't tell us the chemistry. PVC can certainly be made strong and flexible, witness plumbing pipes.

    Kawai's plastic is ABS, Acrylonitrile butadiene styrene, though the current formulation includes carbon fiber. Wiki says ABS is harmed by sunlight - not a likely problem with a piano action, except under extraordinary circumstances.
    Fred Sturm
    University of New Mexico
    fssturm@unm.edu
    http://fredsturm.net
    "The true sign of intelligence is not knowledge, but imagination." - Einstein
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  • 5.  RE:History of Action Plastics?

    Posted 02-15-2013 05:50
    There are few instances of the use of plastics in the UK but one piano manufacturer immediately springs to mind - and that one, most interestingly, is Irish. This company named Lindner manufactured both Grand and Upright pianos with totally unconventional designs. Though I have only come across one example of their baby Grand I was intimately involved with one of their small Uprights - as owner. This piano I had condemned with good reason since the keys were falling out. But what was really interesting was the Company's new approach to old conventional designs. For a start the metal frame was pre-constructed from lengths of iron welded to shape - like farm machinery. Then the keyboard was totally new in concept - the keys were made of hollow plastic with many adjustment and insertion points. For example the 'touch' was adjusted by a plastic screw right through the end of the key. The key frame was  made from channelled extruded alloy . The balance rail was particularly interesting since there were two channels - one for the Sharps and the other for the Naturals for fixing points. Clock spring was used as the pivotal point in each key and each end of a length of clock spring was inserted into a plastic connector - both connectors were different. The one which was inserted into the key was round, split at both ends - one to take the spring, and had 'tines'' to lock it in place in the hole in the underside of the key. The other connector was more interesting and looked as though it had been cut off from a length of extruded plastic in the form of a capital 'R'. This was pushed into the appropriate channel of the balance rail. This form of fixing was common to all action parts for the main action rail was also of extruded alloy with channels for: Damper 'R' flange, Hammer Butt flange and Lever flange. Note - these flanges were simply pushed into place and could be slid side-ways - both action parts and keys - for lining up purposes. The action parts were of alloy  - the Lever being bifurcated to take the 'tape' - which wasn't tape but woven nylon cord terminating in a 'cap' to be pushed on to its bifurcated part of the Lever. The other bifurcation took the check block. I think you have another name for Lever in the US. The other interesting point is - there were no scres in the action at all. The action was captivated in place by spring clips at each end. Another interesting aspect was that by removing the two pedal rods and two bolts the whole keyboard could be hinged down - rather like a 'ships' piano. When I condemned this Lindner it belonged to a friend who was Head of Music at a Prep School. The tonal quality of the piano was exceptional but the piano was let down by disintegrating keys and action parts. Being a very small piano I was able to put it in the back of my Estate car and take it home. I had a new keyboard made by Fletcher & Newman and the piano was back in business. However the action problems wouldn't go away so easily and I sold it for a profit to a dealer. Another interesting afterthought about this Irish Company was that when in the 60's (I think) they went into liquidation or sank in the bog - or whatever they do in Ireland - they paid off their workforce in Pianos......  (and, of course, it could be true!) I just wish I had some photos of it! The concept would astound you.  Michael (UK)

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    Michael Gamble
    semi retired
    Brighton
    01273813612
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  • 6.  RE:History of Action Plastics?

    Registered Piano Technician
    Posted 02-16-2013 17:37
    There was an American piano with an all-plastic action, Thomas by name, "Manufactured by Thomas Organ Co., division of Warwick Electronics, Sepulveda, California." I have a bad quality xerox of a manual describing it and giving instructions for maintenance (the words are clear, but most of the illustrations, the photos, are pretty worthless for any detail at all). Sounds very much like the Lindner: light weight (under 300 lbs), plastic keys that (it describes) don't ride on a pin, but on a "small steel spring." Everything is screw adjusted (key height and dip), frames all aluminum. Reverse crown soundboard, soundboard and pinblock "impregnated" with epoxy. It looks like (in one of the bad photos) the key bed can hinge down. Lots and lots of details of how this was a revolutionary design (including a reverse thread tuning pin - not sure why they thought that was a good thing). I believe the plastic was the same as the kind that became brittle, and they disintegrated, from stories I have heard. I never saw one.

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    Fred Sturm
    University of New Mexico
    fssturm@unm.edu
    http://fredsturm.net
    "The true sign of intelligence is not knowledge, but imagination." - Einstein
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  • 7.  RE:History of Action Plastics?

    Registered Piano Technician
    Posted 02-16-2013 17:47
    Fred,
    I had a Thomas piano for awhile.  Part of the reason I took it on as a project was that my first mentor, Jim Jeffers, RTT, was involved in the production in the Republic of North Ireland.  In your manual, if it shows two men lifting the piano, one of them is Jim.

    It had a sweet tone and the keyboard was hinged so that it could fit inside the knee board for shipping.

    Very creative methods of adjusting lost motion, key dip, key height etc.  Thomas was creative.

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    Larry Messerly, RPT
    Bringing Harmony to Homes
    www.prescottpiano.com
    larry@prescottpiano.com
    928-445-3888
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  • 8.  RE:History of Action Plastics?

    Posted 02-16-2013 17:54
    Sounds like it was a stencil piano made by Lindner.
    The wippen/whippen was just a stamped out piece of aluminum, bent to work. The action tape was a piece of cord with a dab of hot melt glue holding it in place.
    Some innovative ideas, but unfortunately, Mickey Mouse manufacturing, with apologies to Mickey.


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    John M. Ross
    Ross Piano Service
    Windsor, Nova Scotia, Canada
    jrpiano@bellaliant.net


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  • 9.  RE:History of Action Plastics?

    Registered Piano Technician
    Posted 02-16-2013 18:45
    I guess from the action diagram that the wipp had a piece of aluminum as its "structural" basis, that served as the check and spoon as well, with a separate protrusion of aluminum serving as bridle. It seems to have had plastic molded to it in the place where it attached to the flange (that snapped into a slot in the rail), and a piece of plastic that served as the heel and to attach the jack. Looks like the damper lever was also probably aluminum. The hammer butt and catcher, as well as its snap in flange, were plastic, with wooden shank and hammer molding. The keys also rode on a sort of flange that snapped into the balance rail.

    So is this one instrument with three names, Thomas, Lindner and Rippen? Or were there competing designs?

    I'll take my manual to the university next time I'm there and scan it, and then post it when I get a chance. (Easy and fast to scan on the copy machine, but what I have is two sided and folded, so putting it back together in a file that makes sense will take some time).

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    Fred Sturm
    University of New Mexico
    fssturm@unm.edu
    http://fredsturm.net
    "The true sign of intelligence is not knowledge, but imagination." - Einstein
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  • 10.  RE:History of Action Plastics?

    Registered Piano Technician
    Posted 02-19-2013 14:34
      |   view attached
    Here, as promised, is the Thomas Piano manual I have scanned and turned into pdf. Really fascinating reading (at least I find it so). I am sorry the photos are such poor quality. I have what is probably a photocopy of a photocopy. BTW, the RLC written in script on the first page is R. L. Coberly, who taught at Grayson County College, and from whom I got this document.

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    Fred Sturm
    University of New Mexico
    fssturm@unm.edu
    http://fredsturm.net
    "The true sign of intelligence is not knowledge, but imagination." - Einstein
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    Attachment(s)

    pdf
    ThomasManual.pdf   3.23 MB 1 version


  • 11.  RE:History of Action Plastics?

    Member
    Posted 02-19-2013 14:38
    awesome.  thanks Fred!  Great bedtime reading.



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    Anne Acker
    Anne Acker Early Keyboards
    912-704-3048
    a.acker@comcast.net

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  • 12.  RE:History of Action Plastics?

    Posted 02-24-2013 07:21
    Yes, Fred, thanks for posting the pdf. This is SO similar to the Lindner Irish piano - even to the bifurcation of the lever. I was very intimately concerned with my Lindner and marvelled at the original thought which had gone into its design and manufacture. There was hardly any component which had not been considered, modified and improved  over the bog-standard upright. I say bog-standard as mine was Irish. I didn't know, though, that the centre pins were solid silver! One amazing feature was the lack of any screws in the action. Everything was press-fitted into grooves in the main action rail. But it was too advanced for the materials used. The leg of the 'R' shaped flanges broke off rendering the whole piano useless. The keys broke occasionally and their pivot springs more than occasionally. I found a source of clock spring and chopped it into suitable lengths to replace them. The unfortunate thing was to try getting those 'R' flanges out of their slot in the balance rail without breakage in order to replace that spring. Another thing I didn't know was the 'thread' on the wrest-pin was, presumably, a Left-hand thread. I wonder why? To get at the wrest pins the whole top of the piano needed to be lifted off - like a long wooden box - to reveal all the innards. I'm amazed no-one has taken advantage of the progress in plastics and revisited this design.  Michael (UK)    . 

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    Michael Gamble
    semi retired
    Brighton
    01273813612
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  • 13.  RE:History of Action Plastics?

    Registered Piano Technician
    Posted 02-27-2013 10:32
    A couple things that occur to me about the reverse thread on the tuning pins:

    If you installed the strings onto the pins, pins already pounded into the block, inserting wire into the becket, you could make the coil and the pin would rise out of the block matching the coils descending toward the block, if that makes any sense. IOW, it could be a production thing, that kind of syncs with the picture in the manual of the tuning pin and pinblock, where the coils are right up against the "upper pinblock."

    In any case, as you tightened the pins, the coil would not approach the pinblock as in the standard design, but would stay equidistant from the block. Which makes it possible to have the coils closer to the block, meaning less flag-poling.

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    Fred Sturm
    University of New Mexico
    fssturm@unm.edu
    http://fredsturm.net
    "The true sign of intelligence is not knowledge, but imagination." - Einstein
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  • 14.  RE:History of Action Plastics?

    Member
    Posted 02-16-2013 18:25
    Fred, that sounds like a Rippen portable piano. Aluminum plate, fold-down keybed. Good for a yacht. I scrapped one, one tech took the plate for decoration, another took the action and keys. I kept the knee board and use it as a portable work table, I place a moving pad on a grand lid, then the board... perfect for field regulation/repair.
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    Regards,

    Jon Page