... of criteria: bit diameter, skirt length, skirt diameter, wall thickness, gauge clearance angle, face design and button insert types.Thread button ... are interchangeable with Atlas Copco’s COP32 34 44 54 64 84, Ingersoll-Rand ‘s DHD3.5,DHD3.5HD,DHD ... as the leading manufactureof the overburden drilling systems,Prodemo’s PCS Concentric Overburden Drilling Systemm, PESEccentric Overburden Drilling System ...