Cleaning and Lubricating a Movement

A movement is cleaned for one reason and lubricated for another. Cleaning removes what should not be there — oxidised oil, metal wear particles, dust. Lubrication puts back a controlled amount of what should be. Doing either without the other produces a watch that runs and then stops early.

What old oil actually does

Watch oil does not simply wear out. It oxidises, thickens, and then dries into a varnish that holds abrasive debris in suspension against the pivot it was meant to protect. A pivot turning in dried oil and ground metal is being lapped, not lubricated. That is why a dirty movement wears in proportion to how long it is left dirty, not to how much it is used.

The visible signs are easy to miss. Oil that looks wet may already have lost its properties. What you look for under magnification is discolouration, a ring of dried residue around a jewel, and any debris in the oil sink.

The cleaning sequence

The lubrication sequence

Oiling is done in a specific order because later steps obstruct earlier ones. Oil the barrel first and the escapement last; oil what is being covered before you cover it.

1. Barrel — grease on the barrel wall, thin film only, and a drop on the arbor bearings.
2. Lower main plate jewels — oil the sink, not the hole.
3. Wheel train — centre, third and fourth wheel bearings, in assembly order.
4. Winding and setting parts — light grease where specified, sparingly.
5. Pallet fork bearings and pallet locking faces — last, and minimally.
6. Never: the hairspring, the balance rim, or the impulse faces of the pallets.

Grease versus oil

Grease is used where oil would be flung off or squeezed out: the barrel wall, gaskets, and slow heavily loaded parts of the winding mechanism. It stays in place and supports loads an oil film cannot. In the barrel it lets the mainspring slip smoothly instead of juddering — but too much and the spring drags in a viscous bath, which is a measurable loss of amplitude.

Half of watchmaking is knowing where not to put oil.