“I cleaned everything, reassembled it, and the amplitude is terrible.” Nine times out of ten the culprit is oiling: wrong lubricant family, wrong quantity, or oil applied to a part that was still dirty. Here is the full logic, part by part.
The one principle everything follows from
The higher the speed and the lower the load, the thinner the oil must be. The heavier the load and the slower the motion, the thicker the lubricant, up to grease. That is why a balance pivot takes a very thin oil while the mainspring barrel wall takes grease. Our lubrication-points table sums it all up on one citable page.
Part by part
Balance pivots: very thin oil, half an oiler drop in the jewel's oil sink, never on a cap jewel already assembled the wrong way round. Fast train (seconds wheel, escape wheel): thin oil, a well-centred meniscus with no overflow onto the plate. Slow train (centre, third): medium oil. Pallet stones and escape wheel: pallet grease applied as a trace on three or four teeth, the wheel then distributing it — epilame treatment is recommended to prevent migration. Barrel: mainspring grease as a thin film on the wall, plus arbor and lid. Winding stem, setting lever, yoke: grease at contact points only. Automatic reversers: dedicated reverser oil, as a trace, never grease.
Quantities: the real skill
An oversized drop is worse than none: it overflows, creeps along the pivot by capillary action, reaches the roller or the hairspring, and collapses amplitude within weeks. Work with a set of oilers coded by tip diameter, under a stereo microscope, aiming for a meniscus that stays inside the oil sink. Workshop rule: if the drop touches the edge of the sink, it is too big.
The five mistakes that keep recurring
Oiling a poorly cleaned movement (oil turns dirt into paste); using a single “universal” oil everywhere; mixing incompatible families by re-oiling without a full clean; oiling wheel teeth (they are not lubricated); skipping epilame on the escapement and then wondering about migration. Add an invisible mistake: keeping oils opened years ago — horological lubricants oxidise and must be stored away from light.
Frequently asked questions
Can one oil serve the whole movement?
No. Required viscosities range from very fluid (balance pivots) to grease (barrel, winding): a single oil gives either excessive friction or a film that does not hold.
Should wheel teeth be oiled?
No. Horological gearing runs dry; only pivots, pallets and heavily loaded parts are lubricated.
How often should a movement be re-oiled?
Lubrication is renewed during a full service with cleaning, typically every 4 to 7 years depending on use. Adding oil to a running movement is a false good idea.
Building your oiling kit? Our oils and oilers sheet covers selection criteria, budget and common mistakes.