... pre-support, slope stabilization , coast, mine, Structure of self-drilling bolt I. Self-drilling hollow anchor bar Outer sidediameterAverageInternaldiameterEffectiveexternaldiameterAver.eff.CrosssectionalareaUltimateloadcapacityYieldloadcapacityAveragetensilestrengthRmAverageyieldstrengthRp0 ... , coupling, spherical nuts, plates, and stopper. MAXDRILL Self-drilling Rock Bolt/ rock anchoring