Boretti SUB7W/SP parallel surface boring gauge 18-50 mm

Used for measuring square bores and extruded profiles, including at great depths.

Built with high-quality material and a very low coefficient of thermal expansion, together with a special transmission system, to achieve very high measuring accuracy. For thousandth-millimetre measurements, temperature influence (e.g., hand heat) is decisive and causes errors; in the BORLETTI-SUBITO boring gauge, temperature-stabilised materials reduce these errors by 1/10 compared with normal boring gauges, making them practically negligible.

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 accuracy.

The instrument repeatability is 0.0005 mm. Linearity over the entire travel of the moving feeler is 0.002 mm max. The instrument’s mobile centring bracket has a spherical sector configuration, which makes insertion easier even if the instrument is not perfectly aligned with the bore.

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