How to address hammer misalignment?

[wolverine2013]

Hi everyone,

Working on a Mark 1 (20-1974) 88-key with significant hammer alignment issues and curious whether this is normal and how others approach repair?
- ~60 wood hammers appear to have been glued in to the plastic hammer arm at an angle (ranging between 1/64 to 7/64")
- Hammer flange drill hole alignment along the action rail appears to vary front to back creating variability in hammer height and slight misalignments in strike line.

Picture below shows the misalignment with the green line highlighting the edge of the plastic arm and red line for the wood hammer.

I've repaired ~40 of the hammers by clamping the hammer perfectly flat and heating the plastic arm close to the plastic/wood connection.  The repair seems to have completely corrected in nearly all hammers, but would love to know if others have had success with other methods and/or know the long term implications of reheating the plastic.

[pianotuner steveo]

This sounds like the best solution for the issue. It is pretty common. I see acoustic pianos, some fine quality, that have hammers glued in crooked too. ( usually just a few at most)  Those are wood to wood, but piano techs also use heat to loosen glue and straighten the hammers.