The optimum range of hole size for blast hole drilling with DTH is 90 mm to 254 mm (3 ½”–10″). Smaller blast holes are generally drilled using tophammer, and larger holes generally use rotary machines.In other applications, like foundation drilling, DTH hammers can be used with single bit in hole sizes up to . 750 mm (30″). With multiple hammer units CD (Cluster drills) drill holes up to 70″ or 1778 mm.
As a rule of thumb, the smallest hole diameter a DTH hammer can drill is its nominal size. A 4 inch hammer will drill a 4 inch (102 mm) hole. The limiting factor is the outside diameter of the hammer, because, as hole diameter reduces, airflow is restricted. Maximum hole size for production drilling is the nominal hammer size plus 1 inch, so for a 4 inch hammer the maximum hole size is 5 inch (127–130 mm).
Choosing the right hammer is largely determined by hole size and type of rock formation. Ideally, the size of the hammer should match the required hole dimension as closely as possible, leaving just enough space for cuttings to evacuate the hole.
| Model | Thread Connection | OD(mm) | Rec.Hole Size | Shank Style | Working Pressure(Bar) |
| CD35 | API 2 3/8" Reg | φ82mm | φ90-φ105 | DHD3.5 CD35 | 1.0-1.5Mpa |
| CD45 | API 2 3/8" Reg | φ99mm | φ110-φ135 | Cop44 DHD340 CD45 | 1.0-2.5Mpa |
| CSD4 | API 2 3/8" Reg | φ99mm | φ110-φ135 | SD4 CSD4 | 1.0-2.5Mpa |
| CQL40 | API 2 3/8" Reg | φ99mm | φ110-φ135 | QL40 CQL40 | 1.0-2.5Mpa |
| CD55 | API 2 3/8" Reg API 3 1/2" Reg | φ125mm | φ135-φ155 | Cop54 DHD350R CD55 | 1.0-2.5Mpa |
| CSD5 | API 3 1/2" Reg | φ125mm | φ135-φ155 | SD5 CSD5 | 1.0-2.5Mpa |
| CQL50 | API 3 1/2" Reg | φ125mm | φ135-φ155 | Cop54 QL50 CQL50 | 1.0-2.5Mpa |
| CD65 | API 3 1/2" Reg | φ148mm | φ155-φ190 | Cop64 DHD360 CD65 | 1.0-2.5Mpa |
| CSD6 | API 3 1/2" Reg | φ148mm | φ155-φ190 | SD6 CSD6 | 1.0-2.5Mpa |
| CQL60 | API 3 1/2" Reg | φ148mm | φ155-φ190 | Cop64 QL60 CQL60 | 1.0-2.5Mpa |
| CD85 | API 4 1/2" Reg | φ185mm | φ195-φ254 | Cop84 DHD380 CD85 | 1.0-2.5Mpa |
| CSD85 | API 4 1/2" Reg | φ185mm | φ195-φ254 | SD8 CSD8 | 1.0-2.5Mpa |
| CQL80 | API 4 1/2" Reg | φ185mm | φ195-φ254 | QL80 CQL80 | 1.0-2.5Mpa |
| CSD10 | API 4 1/2" Reg API 5 1/2" Reg API 6 5/8" Reg | φ225mm | φ254-φ311 | SD10 CSD10 | 1.0-2.5Mpa |
| CN100 | API 6 5/8" Reg | φ225mm | φ254-φ311 | NUMA100 CN100 | 1.0-2.5Mpa |
| CSD12 | API 6 5/8" Reg | φ275mm | φ305-φ445 | SD12 CSD12 | 1.0-2.5Mpa |
