Boretti interchangeable boring gauges SUB17W 50-230 mm

Built with high-quality material and a very low coefficient of thermal expansion which, together with the special transmission system, enables very high measurement precision. For thousandth measurements, the influence of temperature (e.g. hand heat) is decisive and causes errors; in the BORLETTI-SUBITO boring gauge, since the materials are temperature-stabilised, these errors are reduced by 1/10 compared with normal boring gauges and are therefore practically zero.

The absence of play in the transfer of the feeler movement to the indicating instrument, obtained by means of the circular segment, is decisive for ensuring precision.

The instrument repeatability is 0.0005 mm. Linearity over the entire travel of the moving feeler is 0.002 mm max. The instrument mobile centring bracket has a spherical sector configuration and this facilitates insertion even if the instrument is not perfectly aligned with the bore.

The instruments with measuring range from 4.5 mm to 20 mm have both fixed feelers and the measuring feeler with hard metal tips. Upon request, centring brackets with hard metal contacts can also be supplied. They can be used in the inspection room, for measuring individual parts, for series part checking, for measurements during machining on machine tools. To facilitate instrument set-up, it is recommended to mount the comparator on the relevant support without performing final locking, and to carry out this operation at the time of instrument calibration, which is easily done using a workpiece with a bore assumed as the reference sample; or by using a suitable instrument (micrometer or other). The boring gauges are supplied in wooden cases without a comparator. For thousandth measurements, the A1, CM1 comparators are recommended; for centesimal measurements, the SC001 comparators. Since it is a comparative instrument, it is necessary first to zero it using the special ATA support, zeroing rings, or by means of sample parts.