Regulation Versus Adjustment

In careful trade usage, 'regulating' a watch means altering its average rate — making a fast watch run slower or a slow watch run faster — typically by moving a regulator index that effectively changes the hairspring's active length, or, in a free-sprung movement, by adjusting small weights on the balance rim. Regulation addresses only the watch's mean daily rate; it says nothing about how consistently the watch holds that rate as position, temperature or state of wind change.

'Adjustment', by contrast, is the broader and more skilled work of making a watch's rate consistent despite those varying conditions, and is where a genuinely high-grade movement is distinguished from an ordinary one. A movement 'adjusted to positions' has been tuned (through poising the balance, correcting escapement geometry and, historically, selective work on the hairspring's shape) so its rate varies as little as possible between orientations such as dial up, dial down, crown up, crown down, and crown left or right; a movement 'adjusted to temperature' incorporates or is tuned around compensation for how temperature changes the hairspring's elasticity and the balance's dimensions, covered in more depth in the dedicated temperature-compensation lesson.

It follows that a watch can be well regulated (correct on average, over a full day, in whatever position it happens to spend most of its time) while being poorly adjusted, so that it gains noticeably in one position and loses in another with the errors merely averaging out; conversely, a well-adjusted watch that has drifted slightly from correct regulation is a comparatively simple fix, whereas fixing poor adjustment usually means returning to bench work on the escapement or balance rather than a simple index movement.

Historical movement markings reflect this distinction precisely: 'adjusted' claims (with a specific count of positions, and sometimes temperature and isochronism as additional named criteria) are a grading statement about the movement's engineering and the care taken in its original finishing, not a statement about its current condition, which may have changed with wear, magnetism, or a careless prior service — a point developed further in the lesson on reading auction and dealer descriptions critically.

Understanding this distinction lets a reader correctly interpret both a watchmaker's service report and a historical grade claim; performing either regulation or adjustment on a real movement is skilled bench work requiring training and a timing machine, and is outside the scope of this conceptual lesson.