Repinning

[Don_Mannino@yca.ccmail.compuserve.com]

     Henry and others,

     Here's my outline for the show and tell portion of my PTG class:

     Tools:
        Center Pins (sizes 18-24)               Center pin punch
        Center pin vises (2)            Spring type gram gauge
        Micrometer                      Flange screw holder
        Side cutting center pin cutters
        Broaches, available from Schaff and APSCO.

          This class is primarily intended to show my method for
     recentering complete sets, but the techniques are also useable when
     repinning the occasional bad center.
     Method:
     1. Remove parts from rail(s).
     2. Evaluate needs (tight, loose, fit in birdseye).
     3. Punch out all pins, separate parts.
     Keep parts in order on bench, the un-bushed parts away from you and
     the bushed parts closest.
     4. Decide which size pin you want to use.  Usually 1/2 size larger
     than the old, but sometimes the same size will work.  The deciding
     factor will be whether the pin is tight in the birds-eye, then whether
     it is tight enough in the bushing.  Be careful - if the pin works
     loose in the birds-eye all the good center pin fitting will be wasted!
     Put a pin of the chosen size in a pin vice.
     5. Select the broach 1 size too small (it should be roughened
     already).  Put it in a pin holder leaving enough smooth pin for the
     flange to pass onto.
     6. Push the first flange on and off the broach once.
     7. Try the fit with the sample pin, use the gram gauge if it seems
     close.
     8. If too tight, run it on the broach a few more times (use your
     judgement) until it fits the pin.  If this requires too many passes,
     or if this broach won't make it fit right, get the next larger broach
     and try again.  The type of cloth and it's age will determine which
     broach and how many passes it will take.
     9. When you have reached the level of friction you are after, pin the
     parts together and try it with the gauge again.  Then test for play or
     sponginess.  You may have to make it tighter than ideal, or even treat
     it with alcohol/water in rare cases (mainly with poor quality cloth).
     Keep in mind that humidity does change the friction some.  Very high
     humidity may add 2 grams of friction, very dry may subtract 2 grams.
     Also keep in mind the location of the piano.
     10. When satisfied with the fit of the first flange, run the next one
     on the broach until it feels like the first.  Try to count the number
     of passes over the rough part of the broach.  When reamed, put the
     parts together, trim the pin, and test the friction again.
     11. Move on similarly until you feel secure with the reaming process.
     12. Ream the rest of the flanges without putting the parts together.
     Slide the flange on the broach, count the passes over the rough part,
     feel the friction on the smooth part, and test with the sample pin
     every now and then.
     13. Assemble the parts with pins, test the friction by hand or with
     the gauge.
     14. Replace parts on the rail, travel and space as necessary.

     Note: When reaming, the affect of the reaming decreases with each pass
     of the rough part of the broach.  The first pass may remove 3 grams of
     friction, the second 1 gram, and the rest hardly any.  Therefore, the
     use of a smaller reamer with many passes will tend to give more
     consistent results.

     Drop me a note if you have any questions.

     Don_Mannino@yca.ccmail.compuserve.com