Broach roughness - Was: Repining flanges

[Isaac OLEG]

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Hello,

Is not roughening with a file adding thickness to the iron wire , not as
much as with a brass center pin but certainly a little ?

My process involve the use of 2 medium files (with crossed lines) and the
thickness certainly grows, I am able to obtain sometime a "one tool does it
all" while controlling the thickness with a micrometer, but it is not really
accurate, more is the use of a center pin wire as a burnished.

I don't  understand how you can obtain a tool that is at the same time a
reamer and a burnishes.

With a center wire (we buy these in 50 cm length) rolling between 2 files
the size grows from one to  2 sizes, depending of the files used.
As these clog and are to be roughened again the tool is changing size and
strength and I have to make new ones on a regular basis.

So I have to develop a feel for the efficiency of the tool, if I do pinning
regularly I keep it, if I don't for some time it takes 10-15 pins to find
the good method.

I am very interested in your broaches, but the sizes seem to differ from the
metric sizes we are used too, so I should make some on metric wires myself.

I've been using piano strings for that, but they are not straight enough
mostly, and some sizes are not common.

How large is the roughened part on your broaches ?

Thanks in advance

Greetings

Isaac OLEG


Isaac OLEG

Entertain et reparation 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

  -----Message d'origine-----
  De : pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org]De la
part de Donald Mannino
  Envoye : dimanche 13 avril 2003 05:48
  A : Pianotech
  Objet : Re: Broach roughness - Was: Repinning flanges


  John,

  I used to do it with the edge surface of a large bastard file, roll the
wire on the workbench, changing the angle to randomize the marks in the
wire.

  I believe Schaff's machinist rolls the wire on a coarse grinding wheel,
but I am not sure.  The Schaff ones are usually perfect.

  Don


  At 03:57 PM 4/11/2003 -0300, you wrote:

    Hi Don,
    Would you enlighten us, on the method used to make the roughness on the
broaches?
    Thank you.
    Regards,
    John M. Ross
    Windsor, Nova Scotia, Canada
    jrpiano@win.eastlink.ca
      ----- Original Message -----
      From: Donald Mannino
      To: Pianotech
      Sent: Friday, April 11, 2003 3:29 PM
      Subject: Re: Broach roughness - Was: Repinning flanges


      Clyde,


      You are right - the old APSCO broaches were really nasty, with the
rough area knurled and much too agressive.  Hopefully Schaff threw them all
out when theybought APSCO, but I don't realyl know.  The rough area is
supposed to be subtly rough, with something like the grit of fine sandpaper,
maybe 320 grit or finer.  The point is that the felt should not be chewed up
when reaming, and the reaming area should not be larger than the smooth
area, or the smooth area would not do a good job of burnishing the cloth.


      If the broach gets clogged up, the cloth has very likely been
lubricated with something that has become gummy.  I run into this sometimes,
and it immediately throws up a red flag.  If the cloth is gummy and sticky,
there's a very good chance that reaming and repinning is not going to be a
permanent solution.  The gumminess will rear it's ugly head again, and the
action will go sluggish.  In this case you might consider cleaning all the
bushings with naptha, then keeping a cloth nearby to clean the broach
occasionally.


      With clean dry bushing cloth, a quick tap on the edge of the workbench
is all that is needed to shake out any wool dust that has accumulated on the
broach.  I have had broach sets that were used to do many, many sets of
action parts that kept working like new.


      Don Mannino


      At 06:45 AM 4/11/2003 -0400, you wrote:
        Friends,


        I discovered quite by accident at a PTG convention, when looking
over tools,
        that the rough part of broaches can be quite different.  I have used
the same
        set for years, and the rough part is not rough enough to "clog up."
They
        always worked fine for me.


        But I came across a set that was so rough that it looked to me like
they stood
        a good chance of removing too much felt.  I would be afraid to use
them unless
        someone else looked at them and said, "Oh, yes, that's the way my
set is, and
        they work fine."  I'm not going to buy such a set just to try it
out.


        Regards,
        Clyde


        David Love wrote:


        > In the process of repinning the action using broaches, I found
that the
        > roughened part of the broach kept clogging with felt which reduced
it's
        > cutting efficiency.


        _______________________________________________
        pianotech list info: https://www.moypiano.com/resources/#archives

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