4-Inch DTH Hammers
Drill King’s 4-inch DTH hammer lineup delivers high-frequency impact and dependable penetration across construction, water well, and geotechnical work. Available in three shank configurations — A40I (IR340), A40Q (QL4), and A40S (SD4).
Bit Range
4″–5″
(101–127 mm)
Impact Frequency
1,350 bpm
Working Pressure
150–350 PSI
SHANK SUPPORT
IR340, QL4, SD4
Why Drill King?
Custom Bits
Whether it’s a new gage diameter, face profile, button layout, or something else entirely, Drill King provides quick turnaround custom bits.
Shank Flexibility
Three models — IR340, QL4, and SD4 — cover the most common shanks ensuring compatibility with existing equipment
Maximized Uptime
All Drill King hammers support field servicing through our repair and rebuild kits, so the hammer never leaves the jobsite.
Versatile Pressure Range
A40 hammers operate from 150–350 PSI (10.3–24.1 Bar), providing efficient performance at low pressure and high-speed penetration at 350 PSI.
High-Impact Frequency
At 1,350 blows per minute, our A40 hammers deliver consistent energy transfer to the bit for faster penetration in hard rock.
Extended Component Life
Premium alloys and wear-resistant surface treatments extend tool life and reduce operating cost.
Technical Specifications
Select a model to view its full parts list, dimensions, exploded-view diagram, and air consumption profile.
HADK- A40I
Top Sub Connection
2-3/8 API REG PIN
Eff. Length
36.41 in / 924.8 mm
OD
3.86 in / 98 mm
Hammer Weight
84 lbs / 38.1 kg
| No | Part Name | Qty | Part Number | 1 | Top Sub | 1 | HPDK-A4002 |
|---|---|---|---|
| 2 | Top Sub O-Ring | 1 | HPDK-A4003 |
| 3 | Choke Set | 1 | HPDK-A4008 |
| 4 | Check Valve | 1 | HPDK-A4007 |
| 5 | C.V. Spring | 1 | HPDK-A4009 |
| 6 | Spacer Ring | 1 | HPDK-A4005 |
| 7 | Make Up Ring | 1 | HPDK-A4006 |
| 8 | Air Distributor | 1 | HPDK-A4010 |
| 9 | Air Dis. O-Ring | 1 | HPDK-A4011 |
| 10 | Cylinder | 1 | HPDK-A4012 |
| 11 | Piston | 1 | HPDK-A4014 |
| 12 | Wear Sleeve | 1 | HPDK-A4001 |
| 13 | Piston Ret. Ring | 1 | HPDK-A4017 |
| 14 | Bit Bearing | 1 | HPDK-A4020 |
| 15 | Bit Ret. Ring | 1 | HPDK-A4018 |
| 16 | Bit Ret. Ring O-Ring | 1 | HPDK-A4019 |
| 17 | Drive Sub | 1 | HPDK-A4022 |
| Complete Hammer | 1 | HADK-A40I | |
| Sealkit (Items 2, 9, 16) | 1 | HPDK-A40SEALKIT | |
| Top Sub Connection | 2-3/8 API REG PIN |
| Eff. Length (in / mm) | 36.41 / 924.8 |
| OD (in / mm) | 3.86 / 98 |
| Hammer Weight (lbs / kg) | 84 / 38.1 |
| Piston Weight (lbs / kg) | 16.3 / 7.4 |
| Working Pressure (PSI / Bar) | 150-350 / 10.3-24.1 |
| Application Bit (in / mm) | 4-5 / 101-127 |
| Rotation Speed (RPM) | 20-45 |
| Make-Up Torque (lb·Ft / N·m) | 2000 / 2712 |
| Rotation Torque (lb·Ft / N·m) | 600 / 815 |
| Frequency (blows / min) | 1350 |
Exploded View — A40I (IR340)
HADK- A40Q
Top Sub Connection
2-3/8 API REG PIN
Eff. Length
39.2 in / 995.6 mm
OD
3.86 in / 98 mm
Hammer Weight
86 lbs / 39 kg
| No | Part Name | Qty | Part Number |
|---|---|---|---|
| 1 | Top Sub | 1 | HPDK-A4002 |
| 2 | Top Sub O-Ring | 1 | HPDK-A4003 |
| 3 | Spacer Ring | 1 | HPDK-A4005 |
| 4 | Make Up Ring | 1 | HPDK-A4006 |
| 5 | Choke Set | 1 | HPDK-A4008 |
| 6 | Check Valve | 1 | HPDK-A4007 |
| 7 | C.V. Spring | 1 | HPDK-A4009 |
| 8 | Air Distributor | 1 | HPDK-A4010 |
| 9 | Air Dis. O-Ring | 1 | HPDK-A4011 |
| 10 | Cylinder | 1 | HPDK-A4012 |
| 11 | Piston | 1 | HPDK-A4014-Q |
| 12 | Wear Sleeve | 1 | HPDK-A4001-Q |
| 13 | Piston Ret. Ring | 1 | HPDK-A4017 |
| 14 | Bit Bearing | 1 | HPDK-A4020-Q |
| 15 | Bit Ret. Ring | 1 | HPDK-A4018-Q |
| 16 | Bit Ret. Ring O-Ring | 1 | HPDK-A4019 |
| 17 | Drive Sub | 1 | HPDK-A4022-Q |
| Complete Hammer | 1 | HADK-A40Q | |
| Sealkit (Items 2, 9, 16) | 1 | HPDK-A40SEALKIT | |
| Top Sub Connection | 2-3/8 API REG PIN |
| Eff. Length (in / mm) | 39.2 / 995.6 |
| OD (in / mm) | 3.86 / 98 |
| Hammer Weight (lbs / kg) | 86 / 39 |
| Piston Weight (lbs / kg) | 16.3 / 7.4 |
| Working Pressure (PSI / Bar) | 150-350 / 10.3-24.1 |
| Application Bit (in / mm) | 4-5 / 101-127 |
| Rotation Speed (RPM) | 20-45 |
| Make-Up Torque (lb·Ft / N·m) | 2000 / 2712 |
| Rotation Torque (lb·Ft / N·m) | 600 / 815 |
| Frequency (blows / min) | 1350 |
Exploded View — A40Q (QL4)
HADK- A40S
Top Sub Connection
2-3/8 API REG PIN
Eff. Length
38.48 in / 978 mm
OD
3.86 in / 98 mm
Hammer Weight
86 lbs / 39 kg
| No | Part Name | Qty | Part Number |
|---|---|---|---|
| 1 | Top Sub | 1 | HPDK-A4002 |
| 2 | Top Sub O-Ring | 1 | HPDK-A4003 |
| 3 | Spacer Ring | 1 | HPDK-A4005 |
| 4 | Make Up Ring | 1 | HPDK-A4006 |
| 5 | Choke Set | 1 | HPDK-A4008 |
| 6 | Check Valve | 1 | HPDK-A4007 |
| 7 | C.V. Spring | 1 | HPDK-A4009 |
| 8 | Air Distributor | 1 | HPDK-A4010 |
| 9 | Air Dis. O-Ring | 1 | HPDK-A4011 |
| 10 | Cylinder | 1 | HPDK-A4012 |
| 11 | Piston | 1 | HPDK-A4014-S |
| 12 | Wear Sleeve | 1 | HPDK-A4001-S |
| 13 | Piston Ret. Ring | 1 | HPDK-A4017 |
| 14 | Bit Bearing | 1 | HPDK-A4020-S |
| 15 | Bit Ret. Ring | 1 | HPDK-A4018-S |
| 16 | Bit Ret. Ring O-Ring | 1 | HPDK-A4019 |
| 17 | Drive Sub | 1 | HPDK-A4022-S |
| Complete Hammer | 1 | HADK-A40S | |
| Sealkit (Items 2, 9, 16) | 1 | HPDK-A40SEALKIT | |
| Top Sub Connection | 2-3/8 API REG PIN |
| Eff. Length (in / mm) | 38.48 / 978 |
| OD (in / mm) | 3.86 / 98 |
| Hammer Weight (lbs / kg) | 86 / 39 |
| Piston Weight (lbs / kg) | 16.3 / 7.4 |
| Working Pressure (PSI / Bar) | 150-350 / 10.3-24.1 |
| Application Bit (in / mm) | 4-5 / 101-127 |
| Rotation Speed (RPM) | 20-45 |
| Make-Up Torque (lb·Ft / N·m) | 2000 / 2712 |
| Rotation Torque (lb·Ft / N·m) | 600 / 815 |
| Frequency (blows / min) | 1350 |
Exploded View — A40S (SD4)
