> 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 > > >
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