Crown EIS 43-R32.BS MX 747.00

New, not used, drill bit, pin bit, d. 43 mm, thread R32, 7 hemispherical pins, front 2 x Ø9 mm, peripheral 5 x Ø10 mm. Angle of inclination of peripheral pins 35?. The flushing holes are 3. Length of the crown - 116 mm. Weight 0.7kg. Confirmed durability of the crown when drilling massive rocks represented by quartzites, with the presence of chloritisation and sericitisation, hidden crystalline structure, hardness coefficient f = 17-18 on the scale of Prof. Protodyakonov. Protodyakonov, on drillability - X, difficult to drill, difficult to explode, moderately abrasive (III class), with mineralisation in the form of phenocrysts and veins of pyrite, less often galena-sphalerite-chalcopyrite-pyrite composition, drilling SBUBoomer 282 - not less than91 spurometer. Persistence is confirmed by the Act (Protocol) of tests at the mines of mining enterprises, approved by the first head.