Nā ʻāpana DTH puʻe makani haʻahaʻa a haʻahaʻa
Pono oHFDluʻu ʻana
Hana ʻia ka drill bit me nā mea hao, ʻoi aku ka lōʻihi o ka lawelawe ʻana a ʻoi aku ka kiʻekiʻe ma mua o nā huahana like, a ʻo ka drill bit e haki i ka pōhaku ma ka hopena a me ka ʻoki. ʻO nā bit drill HFD he kūpaʻa ʻaʻahu ikaika a kūpono ia no ka wili ʻana ma ka palupalu a me ka paʻakikī (9-grade drillability of rock, hard rock drilling), i hoʻohālikelike ʻia me ka bit maʻamau, ʻoi aku ka nui no ka wili ʻana i ka pōhaku papa 6-8 he koʻikoʻi ka hopena.