Naw not infinitely adjustable so much as -finely adjustable-,
after crude ball park adjustment for initial fitting.
Vernier cam sprockets similar usage.
Definitions of vernier on the Web:
* French mathematician who described the vernier scale (1580-1637)
* vernier scale: a small movable scale that slides along a main scale; the small scale is calibrated to indicate fractional divisions of the main scale
* A secondary scale with finer graduations than the primary scale of a measuring device; the vernier measures between graduations of the larger scale