Product Overview
The LEANOMS 4 inch DHD340 DTH hammer with foot valve is intended for pneumatic down-the-hole drilling in medium to hard rock. Select it together with a compatible bit and foot valve, then check the drill string and compressor requirements. Hammer size alone does not establish suitability for a project.
DHD340 product photograph. This page covers the version requiring a foot valve.
DHD340 Hammer Configuration
This model is part of the DHD/COP DTH hammer series. The 4-inch designation identifies the hammer size class rather than the finished hole diameter. The selected bit diameter must fall within the operating range approved for the supplied assembly.
| Item | Product Configuration |
|---|---|
| Model | DHD340 |
| Hammer size class | 4 inch |
| Drilling method | Pneumatic down-the-hole drilling |
| Foot-valve configuration | Requires the specified matching foot valve |
| Bit and drill string | Select against the approved shank, retaining arrangement and backhead connection |
Start with the required hole diameter and existing bit shank. Then confirm the compressor output and drill string connection. These checks help prevent ordering a hammer that cannot operate correctly with the equipment already on site.
Working Principle and Foot-Valve Matching
Compressed air travels through the drill string and drives the piston inside the hammer. The piston strikes the bit near the bottom of the hole, while rotation advances the cutting pattern. Flushing air carries cuttings away from the bit and towards the surface.
For a fuller explanation of the pneumatic drilling cycle, see how a DTH hammer works. Actual penetration depends on the formation, bit condition, air supply, flushing and operating settings.
Foot-valve requirement
This DHD340 version requires a matching foot valve. Its dimensions and installation must follow the approved specification. Do not omit it, modify it or substitute a component from another hammer design without technical approval.
Matching the Hammer, Bit and Drill Pipe
When reviewing matching DHD/COP DTH bits, confirm the exact shank rather than relying on the series name. Similar-looking bits may have different retaining details or foot-valve configurations.
Verify the bit shank and foot-valve arrangement against the product drawing.
- Bit shank and retention: check the shank profile, dimensions and retaining arrangement.
- Foot valve: confirm the specified component, its condition and installation.
- Backhead connection: verify the thread against the drill pipe and any proposed adapter.
- Complete drill string: review pipe dimensions and the rig's operating limits. A connection that screws together does not establish that the complete assembly is suitable.
For replacement enquiries, provide photographs of the hammer marking and bit shank, together with available drawings. Photographs support identification; the approved dimensions establish the final match.
Application and Equipment Selection
Evaluate the DHD340 against the actual drilling conditions, rather than selecting it solely because the project involves water wells, quarrying or construction. The following checks help turn an application description into a useful equipment enquiry.
| Site Condition | Selection Priority | Information to Provide |
|---|---|---|
| Medium to hard rock | Match the hammer and bit to the hole requirement | Rock description, hole diameter and current tools |
| Abrasive or changing formations | Review bit selection and observed wear | Used-bit photographs and drilling observations |
| Groundwater or increasing depth | Assess flushing and available air supply | Depth, water conditions and compressor output |
| Existing rig and drill pipes | Verify connections and equipment limits | Rig model, pipe dimensions and thread details |
Confirm hole diameter and compressor output early in the selection process. Both pressure and delivered air flow matter; a pressure rating alone cannot establish whether the proposed drilling assembly has adequate air supply.
Common Matching Errors to Avoid
Selecting by hammer size alone
A 4-inch size label does not confirm the bit shank, hole range or connection. Buying before checking these details can result in an unusable assembly and additional replacement costs.
Mixing foot-valve and foot-valve-free configurations
These configurations should not be treated as interchangeable. Confirm the exact hammer and bit combination before installation. An incorrect component can prevent proper operation and introduce a risk of component damage.
Increasing bit diameter without reviewing the system
A larger bit changes the demands on the drilling assembly. Check the approved hammer range, compressor and rig before changing diameter. If another size is required, evaluate the 5 Inch DHD350 DTH hammer as a separate matched configuration.
Inspection and Maintenance Priorities
Maintenance planning should cover lubrication, contamination control, bit condition and connection wear. Follow the operating manual for the supplied hammer; oil grade, quantity, tightening requirements and wear limits are model-specific.
- Check the specified lubrication system before operation. Inadequate lubrication can accelerate internal wear.
- Keep exposed tool joints protected during handling and storage to reduce the entry of dirt and drill cuttings.
- Inspect the bit, chuck, threads and foot valve during scheduled servicing. Compare wear with the applicable limits.
- If impact or flushing changes unexpectedly, stop and investigate the air supply, assembly and component condition before continuing.
DHD340 Hammer FAQ
Does a 4-inch hammer drill a 4-inch hole?
Not necessarily. Hammer size class and bit diameter are different selection details. The bit determines the nominal cutting diameter, while the hammer must support the selected bit and operating conditions. State your finished-hole requirement when requesting a quotation rather than specifying only the hammer size.
Can I reuse bits from another DHD340 hammer?
Reuse should follow a compatibility and condition check. Confirm the full hammer designation, shank dimensions, retaining arrangement and foot-valve specification. Provide the existing bit drawing or measurements. A familiar model name or similar appearance is not sufficient evidence that a worn or differently configured bit is suitable.
What compressor information is needed?
Provide the compressor model, working pressure and delivered air flow at that pressure, together with drilling depth and groundwater conditions. These details support an assessment of the air supply for the intended assembly. Use the operating requirements of the supplied DHD340 version when selecting equipment.
What should I provide for replacement spare parts?
Send the complete hammer model, available part numbers, photographs and the relevant drawing. Identify the component being replaced and describe any observed damage. Parts from a foot-valve-free version should not be ordered for this version without confirmation of interchangeability against the manufacturer's documentation.
How should a contractor assess a test order?
Record the formation, hole size, depth, compressor settings, operating conditions and maintenance routine. Track drilling time, interruptions and component wear. Compare results under similar conditions so that changes in ground or equipment do not obscure the assessment. Agree on the test configuration before placing a repeat order.
Request a Matched DHD340 Quotation
Share your hole diameter, rock formation, drilling depth, compressor pressure and air flow, rig model, drill pipe dimensions and thread. Include the existing hammer and bit details if you are replacing an assembly.
For distributor enquiries, specify the required quantities, model mix, spare parts and destination. Contact LEANOMS at info@leanoms.net to discuss a matched hammer-and-bit quotation.
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