Alesametro subito 280-410 mm

Built with high-quality material and a very low coefficient of thermal expansion which, together with the specific transmission system, enables very high measuring accuracy. In the case of thousandth measurements, the influence of temperature, for example hand heat, is decisive and leads to 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 accuracy.

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

The instruments with a measuring range from 4.5 mm to 20 mm have both fixed feelers and the measuring feeler with hard metal tips. On request, centring brackets with hard metal contacts 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 the final locking, and to carry out this operation when registering the instrument, which can be done easily 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, A1 and CM1 comparators are recommended; for hundredth measurements, SC001 comparators. 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 workpieces.