In this work an optical instrument for measuring tilt is described. The device is compact, requires no special handling
and can measure variations in tilt of the order of 0.5 arcsec, although this value can be suitably modified by changing
the setup parameters. The instrument was developed as a tiltmeter using a liquid surface as reference surface. The
inclination is obtained by measuring the longitudinal displacement of a laser beam after being reflected from the surface
of the liquid. The application of the instrument for measuring the tilt of the spindle of a polishing machine of large
dimensions is presented.