Field notes (March)
4 March
Spent the morning at the bench with the regulator movement that came in last week. The mainspring had lost roughly a third of its tension, which explains the four-minute drift the owner kept writing to us about. Cleaned the pivots, re-oiled the third wheel, and left it running face-up overnight to see whether the rate settles on its own before I commit to replacing anything.
9 March
Rate held at +2.4 seconds a day in three of the five positions, which is closer than I
expected after so little intervention. The remaining drift shows up crown-down, so the
balence staff is the likely culprit rather than the
escapment itself. Ordered a replacement staff from the workshop in
Neuchâtel and noted the serial in the ledger. If the new staff does not bring the
positonal variation under a second, the whole train comes apart
again and I start from the barrel.