Efficient repining method by Renner

David's Email ilvey@sbcglobal.net
Thu, 22 May 2003 15:49:18 -0700


Rebushing rather than repinning at what size?  21.5?  Interesting that in
Renner's technical info they didn't mention the most important aspect, i.e.
the pin must be tight in the birdseye.

David I.

----- Original Message ----- 
From: "Isaac OLEG" <oleg-i@wanadoo.fr>
To: "College and University Technicians" <caut@ptg.org>
Sent: Thursday, May 22, 2003 12:10 PM
Subject: Efficient repining method by Renner


> Hello everyone,
>
> I received today a nice pamphlet coming from Renner Germany, that was
> send to me because I ordered a set of reamers (neat cool burnishes I
> received in fact).
>
> As I asked how they use these tools in the factory they send me the
> translation of a training that was given by a head tech for the German
> technicians in 95.
>
> A few points seem important so I will tell you about.
>
> The original pinning in Renner actions is machine done, when worn or
> too much play, we use to insert a pin one size larger (usually 1.300
> mm original, 1.325 to 1.400 in repair mode.)
> For older instruments, using oversized cnterpin is not recommended,
> but what is called "complete rebushing" is considered that mean,
> drilling or pushing out the old bushing cloth and using a new one with
> a decently pin size.
>
> The important points I notice are :
> Relative humidity in the shop and customer's place is to be taken in
> account for these jobs.
>
> When extracting or inserting a center, we may always go in the same
> direction, than originally, that is, push with the center pin
> extractor on the side of the pin which was not cut and that is clearer
> (nickel plated sometime).
>
> The use of long center pins (25 cm or approx 1 " long) is said to be a
> better solution, as the insertion of the center burnish well the
> inside of the bushing.
>
> After reaming, burnishing is of prime importance, and may always be
> done in ONE DIRECTION only, so the fiber stay neat and well oriented.
>
> A "pinning plank" is done, to be hold in the bench cauls. It allows
> the use of the long center pins it is a hardwood plank with a large
> saw kerfs on the top, and possibly a little metal plate. After the
> pointed end of the long center is inserted thru the flange and the
> Birdseye, the part is laid on the plank, and the point of the center
> is hold in a flat pliers, then pulled thru all along preferently in
> one pass (while the flange is stopped by the plank).
> if one use pre cut centers, a burnisher is to be used, but it may as
> well be used in one direction only.
>
> For complete rebushing, with new felt, the strip of special bushing
> material may be hold in a wise, and all the flanges inserted at once
> after the
> bushing have been :
> sized, passing in a little metal plate drilled with 3 different holes
> (sold by Renner - dimensions of holes on demand)
> Graphited with a first class graphite stick as the one sold by Renner
> (no joking)
> glued on the external side with hot glue - pre-glued strips as sold by
> Renner have only to be misted with a sponge.
>
> 10 hours after it is possible to cut flush and ream the new bushing
> (30 min only with the pre glued material)
>
> They give a recipe for easing the pinning with a 5% water 95%
> distilled water to be used for hammers, or 70% alcohol and 30%water
> when the pinning may be more firm as for whippen, dampers, etc.
>
> They say also it is forbidden to use any oil on the bushings, because
> it cause soft bushing felt, stain on the flanges, accumulation of
> dirt, problems when trying to repin or rebush because the felt is not
> holding on the wood...
>
> For what is worth, nowadays the fiber direction and the insertion
> direction makes a lot of sense to me.
>
> Hope you have find some interest in these so well know things !
>
>
> Another good trick :
> if the Birdseye is showing too much friction on the flange, (too
> thick) , press the flange - and work the part while pressed - with a
> "duck nose" or flat large pliers (as for dampers) that have a 3mm hole
> drilled on one side. That way the wood is burnished and friction
> lessened (the hole avoid warping of the center pin.
>
>
> Best to all.
>
>
> Isaac OLEG
>
> Entretien et réparation de pianos.
>
> PianoTech
> 17 rue de Choisy
> 94400 VITRY sur SEINE
> FRANCE
> tel : 033 01 47 18 06 98
> fax : 033 01 47 18 06 90
> cell: 06 60 42 58 77
>
> >
>
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