Product Description
The 40–42 mm four-tooth tapered button family covers two closely spaced hole gauges for mine headings, utility holes, and rock excavation with tapered-rod equipment. It gives a crew a defined diameter choice without changing the basic four-contact impact structure. Selection should follow the construction drilling application archive and the rock description in the medium formation archive. These gauges do not confirm that either bit fits every nominally tapered rod, and they are not suitable for drilling unsupported loose fill.
The source states a carbide button bit, four teeth, and a tapered connection. An alloy-steel body supports the fixed carbide contacts and transmits impact through the socketed end. The 40 and 42 mm options may support different hole plans, but the filename does not supply the taper angle, socket diameter, skirt profile, or button placement. Treat the products as one documented family with two verified gauges, not as interchangeable parts. A mating-rod sample or dimensional drawing is required before either size is released to the field.
Apply 1,000–3,000 lbf/in of bit diameter and 25–60 RPM. Use lighter initial loading when starting the hole, crossing joints, or changing between the 40 and 42 mm gauges, because contact and return behavior can differ. Medium and hard rock are suitable planning classes; abrasive intervals require frequent gauge checks. Flow remains unspecified because the correct air volume depends on rod bore and hole conditions. The explicit limitation is the absent taper standard. General drilling references are available from the IADC.
