teflon flange and bushing

Phillip Ford fordpiano@earthlink.net
Sun, 15 Dec 2002 20:48:49 -0800



>  I might be reluctant to use plastics in a piano that was meant to last a
>long time since I don't believe there is yet a track record for longevity
with
>the plastics available now.

Kawai has been torture testing ABS flanges for nearly 30 years. The first 
ones installed still test stronger than new wood. I'd guess it was probably 
fairly safe by now, since pianos don't last longer than that anyway... right?

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I wasn't aware of that.  30 years is a pretty good life expectancy for an
action part that gets regularly used and serviced (and replaced).  So, this
shouldn't be a limitation.
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>         In regard to the question of teflon flanges with teflon bushings 
> - if you're
>making the flange out of teflon why do you even need a bushing?  Just drill
or
>ream the hole to the proper size for the pin.  This would seem to speed
things
>up in the assembly process.

Teflon is too soft to work as a flange, and when a ham handed field tech 
butchered one, the whole flange would have to be replaced - and they'd be 
slippery and hard to handle. <G>

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I agree about the slippery part.  There'd be a lot of flanges lost under the
bench <G>.  I'm not sure about the soft part.  See:

http://www.dupont.com/teflon/chemical/properties.html

The numbers look like they might be in the hardwood and felt range.  Also,
there are many polymer formulations containing teflon that aren't pure teflon
that would probably work.  As far as ham handed technicians the same would
apply to felt bushings (hey, there's always a number 25 pin if you messed up
the last three attempts).  If you messed up one attempt at repinning you could
try it again several times with the teflon flange as well.  And a teflon
flange should be as easy to replace as a felt bushing.  Also, I was thinking
of this more as an application for low end pianos where the cost of assembly
is a primary consideration.  After they're put together there doesn't need to
be any service, right?
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>I'm surprised some manufacturer hasn't thought of this already
>(maybe they have and I don't know about it).

They did, but decided against. Didn't you get the call?

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I'm always the last to know.
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>As to the comment that all wood parts would have to be made of ABS (or other
>plastic), why?  Why can't you mix?  Some parts could be plastic and some
parts
>wood, as seems appropriate.

You can. It's done, and it seems quite appropriate. Shanks are still wood, 
even if the rest of the action is ABS.

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Wonder why they don't like ABS for the shanks?
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>         About the Kawai actions with ABS parts?  I have not seen one of 
> these yet.
>What sort of bushings do these use?

Bushing cloth, like wood ones (only less trouble). They're very nice actions.

Ron N

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I'm going to make it a point to look for one.

Phil F
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