particle board

[David ilvedson]

> Date:          Sat, 20 Sep 1997 08:17:45 -0700
> From:          Delwin D Fandrich <pianobuilders@olynet.com>
> Organization:  PianoBuilders/NW
> To:            pianotech@ptg.org
> Subject:       Re: particle board
> Reply-to:      pianotech@ptg.org


It seems to me that some sort of a machine threaded insert might 
be the answer where wood screws are used in MDF.  

David ilvedson, RPT
Pacifica, CA

>From a manufacturers point of view MDF does have a number of 
advantages.
> It is consistent in dimension and working characteristics. It's easy to
> work with_it machines well, albeit with the requirement of carbide or
> diamond cutting tools. As your father pointed out it is reasonably
> "strong" and stable. Used correctly, it doesn't warp or twist (much). It
> takes glue well. And, perhaps best of all, it is environmentally sound
> in that what would otherwise be wood scrap can be used in its
> manufacture. In fact, I'd go so far as to say that without the use of at
> least some MDF, the piano industry would be out of business by now.
> There simply isn't enough solid wood left in our forests to go around. I
> live in what used to be a huge temperate rain forest. It seemed
> inexhaustible. It wasn't. 
> 
> On the down side, it is heavy and it is highly susceptible to (dare I
> use the word again) creep under load. This combination makes its use
> problematic for one of the most logical applications in piano
> building_the grand lid. I've already seen too many sagging lids on
> pianos whose owners leave the lids open consistently. And you ever tried
> to lift an MDF lid on a seven foot piano by yourself? No. Of course you
> haven't. You're still here and able to read this.
> 
> But perhaps its most significant limitation for pianobuilders is its
> dislike for conventional fasteners. Try using a common wood screw and
> you're fresh out of luck. It is not possible to use even a specially
> designed MDF screw in the stuff more than once or twice. This is the
> characteristic that probably offends most piano technicians and limits
> the stuffs usefulness in pianos. We need the ability to disassembly and
> reassemble the piano repeatedly during its lifetime. This is not
> generally a requirement with other types of furniture so you don't hear
> as many cries and moans from that segment. If the fastener issue is
> adequately dealt with MDF can be used effectively in many applications
> in the piano. Unfortunately, as often as not, plain old screws are used.
> (In fairness here, I should point out that I'm not all that familiar
> with the specifics of how MDF is used by manufacturers like Yamaha or
> Kawai today. I do know that they also have a dark past. One hopes
> they've seen the light.) 
> 
> 
> --ddf
> 
> 
>