Yes - thanks Joe - my most profound apologies to "Al Jolson" AlanD (who's memory & spelling is pretty atrocious at the best of times and who's spell checker does not have "Jolson" in it anyway) >-----Original Message----- >From: owner-pianotech@ptg.org >[mailto:owner-pianotech@ptg.org]On Behalf >Of Joe & Penny Goss >Sent: Sunday, August 23, 1998 1:15 PM >To: pianotech@ptg.org >Subject: Re: Plate - Grinding > > >ALAN, >Do you mean Al Jolson? >Joe >---------- >> From: Alan W Deverell <aland@casa.co.nz> >> To: pianotech@ptg.org >> Subject: RE: Plate - Grinding >> Date: Saturday, August 22, 1998 6:48 PM >> >> Peter & Others - I might have added (although most may >already know): >> >> 1) Cast Iron is quite brittle - surface defects in stress areas can >> lead to fracture cracks - can lead to eventual breaking of the >> casting. >> >> 2) Cast Irons is NOT very ductile - do NOT hammer or >subject to high >> impact/shock loadings (drop on to a concrete floor). There is an >> exception to this, in that, "peening" a welded crack to unify the >> stresses introduced by welding - but this is the preserve >of a skilled >> cast iron welder). >> >> 3) If you progressively "drill out" a line along the 25mm >you wish to >> remove (as someone suggested) you MUST ensure that you >grind away the >> drillings so as to ensure a clean uniform blended (fettled) surface >> conforming to the sculpture of a GOOD plate design, >otherwise, if the >> are any loadings throughout the area removed then the >caution of "1)" >> above may be revealed. >> >> 4) Some Piano Castings are pretty rough and "fettling" of >the castings >> not properly undertaken. I believe that tidying up with a >die-grinder >> etc. (as described below) is often appropriate/essential to a >> professional re-build before the plate is re-painted. >> >> 5) The invasion of Cast Iron dust included the human skin >etc., so, if >> face, scalp, hair and hands etc. are not covered then you will >> certainly require to take a shower otherwise you may look like Al >> Johnson, or some other character out of the Black & White >Minstrels. >> >> AlanD (who has often looked like Al Johnson but never sung >like him) >> >> PS - Not sure if Belgium knows about Al Johnson and the >"Black & White >> Minstrels" >> >> >-----Original Message----- >> >From: owner-pianotech@ptg.org >> >[mailto:owner-pianotech@ptg.org]On Behalf >> >Of Peter Kestens >> >Sent: Sunday, August 23, 1998 7:17 AM >> >To: pianotech@ptg.org >> >Subject: Re: Plate - Grinding >> > >> > >> >Alan, >> > >> >Thanks a lot for your information. I hope it all will work well. >> >Peter >> >-----Oorspronkelijk bericht----- >> >Van: Alan W Deverell <aland@casa.co.nz> >> >Aan: pianotech@ptg.org <pianotech@ptg.org> >> >Datum: vrijdag 21 augustus 1998 1:37 >> >Onderwerp: RE: Plate - Grinding >> > >> > >> >>Although I have never had to remove as much as 25mm >(1"), my work on >> >>Older Cast Iron Plates has all been done with the aid of >> >the following >> >>equipment: >> >> >> >>1) Tool Makers Die Grinders (electric or pneumatic) fitted with >> >>appropriate "Mounted Points" up to 1" diameter and shaped, using >> >>"dressing tools" to suit the "re-fettling" job. >> >>2) Angle Grinders (electric or pneumatic) fitted with >> >appropriate grit >> >>disks and sanding pads. >> >>3) Sanding "bobs" (mounted in electric or pneumatic >drills) to level >> >>some of the surface markings. >> >>4) Hand sanding using cloth backed "emmery paper" strips. >> >> >> >>Any good engineering supply shop should be able to >advise you in the >> >>selection of all the gear. >> >> >> >>I recommend that you practice the skills on something unimportant >> >>before you begin in earnest and that you ensure that the >> >25mm you wish >> >>to remove is NOT going to compromise the structural >integrity of the >> >>plate. >> >> >> >>Warning - Cast Iron DUST, produced by these methods, is >> >VERY invasive >> >>and it is essential to wear appropriate breathing >apparatus, safety >> >>glasses and ear muffs etc. and to vacuums clean/sweep up >afterwards. >> >> >> >>AlanD (who learned these basic skills, 25 years ago, porting and >> >>polishing the cylinder heads of racing engines) >> >> >> >>>-----Original Message----- >> >>>From: owner-pianotech@ptg.org >> >>>[mailto:owner-pianotech@ptg.org]On Behalf >> >>>Of Peter Kestens >> >>>Sent: Friday, August 21, 1998 8:12 AM >> >>>To: pianotech@ptg.org >> >>>Subject: plate >> >>> >> >>> >> >>>Hello, >> >>> >> >>>I'm "truying" to rebuild an old (ugly) german piano to a >> >>>(less or more) >> >>>decent one. Lets say I do it as an exercise. >> >>>For this, I've rescaled the old stringscale but I've also to >> >>>make a totally >> >>>new bridge because the program (=Parsons) showed strings >> >>>that are about 30 >> >>>mm to long (and this means inharmonicity is very bad). I >> >>>also have to remove >> >>>some metal from the plate: the new bridge comes about where >> >>>two screws now >> >>>fasten the plate. There is place to make new screw-holes 25 >> >>>mm higher but >> >>>what is the most easy way to remove about 25 mm of metal >> >>>without to much >> >>>damaging the plate. The screw-holes are for the moment >> >>>left and right >> >>>from the treble bar from the plate. Thanks a lot for your help. >> >>> >> >>>Peter >> >>> >> >>>KESTENS.P@DEBCOM.BE >> >
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