Plate - Grinding

[Joe & Penny Goss]

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
>