Summary
The COP 44 GOLD Hammer from ROSCHEN has been re-engineered around a guided chuck casing design that holds a straight 115 mm hole through broken, collapsing and layered ground, giving mining and construction crews a 4-inch class down-the-hole tool that survives repeated rebuilds. Built on the TD 40 shank platform with API 2 3/8 in Reg, API 2 7/8 in Reg and CUBEX #24 pin connections, the hammer covers a 110 mm to 130 mm hole range from a single body. Hardened alloy steel, an outer wear coating, a three-start chuck thread and an internal air cushion system combine to keep penetration flat across a shift instead of fading after a few hundred metres. This release explains how the hammer is built, why production drillers specify it, and how to match it to your rig, air package and bit. Quarry operators and contract drilling fleets evaluating cost per metre will find the full technical position below, together with a service and rebuild programme designed to keep the COP 44 GOLD Hammer working rather than replaced.
What: What the COP 44 GOLD Hammer Actually Is
A down-the-hole (DTH) hammer is a valveless pneumatic percussive tool that travels at the bottom of the drill string directly behind the bit. Compressed air is fed down the drill pipe, cycles through the hammer's internal piston chamber and drives a piston against the bit shank at roughly 800 to 1,500 blows per minute, depending on air volume and back pressure. Because the impact is generated metres below the rig, at the rock face, no energy is lost through rod flex, thread losses or hole friction — the entire strike reaches the bit. The exhaust air then sweeps the face and lifts cuttings up the annulus, so a single air supply does both jobs: percussion and flushing.
The COP 44 GOLD Hammer is the 4-inch class member of that family. Physically it is a steel cylinder assembly comprising a top sub, a check valve, a case, a piston, a chuck and a bit retainer, with an overall length and mass intended for rigs in the 4 to 8 tonne class and compressors delivering roughly 7 to 12 bar at the hammer. Its shank is TD 40, the interface that transfers impact energy and rotation into the bit. The body accepts API 2 3/8 in Reg, API 2 7/8 in Reg and CUBEX #24 pin connections, which means the same hammer body can follow whichever drill string a fleet already owns.
Two structural details define this tool. First, the guided chuck casing variant fixes the casing and the drill string on a common axis, so the hammer cuts a true 115 mm hole through overburden and broken rock rather than wandering. Second, the three-start chuck thread engages and releases in roughly a third of the rotation required by a single-start thread, cutting bit change time and thread galling. Inside, an air cushion system absorbs part of the impact shock before it reaches the case, and a protective coating on internal components allows the COP 44 GOLD Hammer to be stripped, re-sleeved and returned to service several times over its life.
Why: The Four Reasons Production Drillers Specify It
Drilling contractors do not buy hammers; they buy metres. Every hour a rig stands idle because a bit will not release, a case is worn out of tolerance or a replacement hammer is three weeks away is an hour of revenue that never returns. That single economic fact is what the COP 44 GOLD Hammer is designed around, and it produces four advantages that matter on a working site rather than on a specification sheet.
First, external wear resistance protects the asset itself. In abrasive rock, the outer case loses diameter long before the piston wears out. A worn case loses hole clearance, reduces flushing efficiency and eventually lets the hammer rattle in the hole. A hardened, coated barrel keeps the body dimensionally stable through long production runs, which is the difference between a hammer that is rebuilt and a hammer that is scrapped.
Second, serviceability translates directly into uptime. The hammer strips down with standard workshop tooling: chuck, bit retainer, piston and case are accessible without a press or a specialist jig. Because internal components carry a protective coating, the body tolerates multiple rebuild cycles. A down-the-hole hammer that can be rebuilt in a shift, using a kit held on site, removes the single longest interruption in a production drilling cycle.
Third, hole quality in overburden stops being a compromise. The guided chuck casing configuration holds the string on axis through fill, sand, weathered rock and fractured zones. Contractors working in mixed face report fewer reamed holes, less casing shoe damage and fewer abandoned holes, which is where the real cost of deviation sits.
Fourth, fleet flexibility reduces inventory. With API 2 3/8 in Reg, API 2 7/8 in Reg and CUBEX #24 pin options and a 110 mm to 130 mm range, one hammer body serves several rig and bit combinations. For a contract driller moving between sites and rock conditions, that is a smaller spare-parts inventory and a shorter decision chain when a hole size changes. Add the three-start chuck thread for faster bit changes and the air cushion system for steadier impact energy, and the commercial case for specifying the COP 44 GOLD Hammer across a production fleet becomes straightforward.
There is a fifth, quieter advantage: parts continuity. A hammer programme is only as good as the kits behind it. Wear sleeves, pistons, chucks, bit retainers and check valves need to arrive on schedule for years, not for one season, otherwise the rebuild strategy collapses into a replacement strategy. Buyers should ask any supplier what happens in year three, when the third rebuild comes due and the original purchasing manager has moved on. A documented parts programme is a far better indicator of long-term value than a headline price.
How: Running the Hammer in Real Applications
Understanding where a hammer actually runs separates a quotation from a technical partnership. The COP 44 GOLD Hammer is specified in three duty classes, each with different priorities for air, bit and service interval.
Open pit and quarry benching. A typical bench hole in granite or hard limestone runs 115 mm to 130 mm diameter, 15 to 25 metres deep, on a 4-inch class rig. Here the hammer operates at high air pressure with a button bit matched to the formation: spherical buttons for hard, brittle rock, ballistic or semi-ballistic buttons where penetration rate needs help in softer, more plastic ground. Because the bench pattern rarely changes, the limiting factor is bit life and case wear — which is exactly what the hardened, coated barrel and the rebuild programme address. Rotation speed is set so buttons index across the face rather than track in one groove, and flush volume is watched at the collar: if cuttings return slows, back pressure rises and impact energy drops before the operator sees it on the gauge.
Overburden and mixed face with casing. The guided chuck casing version is built for ground that will not stand: fill, sand, gravel, weathered rock, old workings. The casing advances behind the bit while the guided chuck keeps the string on axis, so the hole enters bedrock at the designed position. The practical parameters shift here — a slightly lower feed force, careful collar control in the first two metres and close attention to casing shoe condition. When the hammer breaks through into hard rock, the same body continues as a conventional 115 mm production hammer, which is why drillers standardise on the COP 44 GOLD Hammer rather than switching tools at the rockhead.
Water well, geothermal and foundation work. In water well and geothermal drilling the priorities are hole straightness, casing clearance and reliability far from a workshop. A hammer that is easy to rebuild and carries spare-part availability after delivery is worth more than a marginally faster tool. The three-start chuck thread matters most on deep, abrasive holes, where operators change bits more often than the schedule predicts.
Matching the tool to the rig. Confirm the shank, the thread and the air package before the hammer leaves the workshop. TD 40 shank, API 2 3/8 in Reg, API 2 7/8 in Reg or CUBEX #24 pin, bit diameter inside the 110 mm to 130 mm range, and a compressor holding pressure at depth, not only at the collar. Lubrication discipline — a steady oil feed matched to air volume — decides whether the air cushion system and coated internals deliver their full rebuild potential. Every unit ships with a test record, torque values and a parts list so the first service is a planned task rather than a diagnosis.
| Parameter | Specification |
|---|---|
| Model | COP 44 GOLD Hammer |
| Shank style | TD 40 |
| Thread connection | API 2 3/8 in Reg, API 2 7/8 in Reg, CUBEX #24 pin |
| Recommended hole size | 110 mm to 130 mm |
| Guided chuck and casing version | 115 mm, API 2 3/8 in Reg |
| Guided casing version | 115 mm, API 2 7/8 in Reg |
| Main application | Mining and construction production drilling |
| Body construction | Hardened alloy steel with protective wear coating |
| Internal features | Air cushion system, coated components, multiple rebuilds |
| Chuck thread | Three start chuck thread |
Four questions we settle before shipment: which thread matches the existing string, whether the bit shank and face profile suit the rock, what air volume is needed at depth, and what rebuild interval to plan for. Answering those four points turns a hammer order into a drilling plan.
FAQ
Below are the six questions buyers ask most often about this hammer, answered in operational terms.
What hole size does the COP 44 GOLD Hammer drill?
The hammer is rated for 110 mm to 130 mm holes. The guided chuck and casing version is rated at 115 mm with an API 2 3/8 in Reg connection, and the guided casing version is rated at 115 mm with an API 2 7/8 in Reg connection. One body therefore covers most 4-inch production drilling requirements without a second hammer purchase.
Which rigs and threads does it fit?
It uses a TD 40 shank and accepts API 2 3/8 in Reg, API 2 7/8 in Reg and CUBEX #24 pin connections, so it follows drill strings already in service on most 4 to 8 tonne rigs. Share your string, shank and compressor specification and we confirm the exact configuration before shipment.
Why choose the guided chuck casing version?
In overburden, fill, sand and fractured rock, the guided chuck keeps casing and drill string on one axis, so the hammer cuts a true hole instead of wandering. Contractors report fewer reamed holes and less casing shoe damage, and the same hammer continues as a normal production tool once bedrock is reached.
How many rebuilds can be expected?
Rebuild count depends on rock abrasiveness, air quality and lubrication discipline. Because internal components carry a protective coating and the body is hardened alloy steel, the COP 44 GOLD Hammer is designed for multiple rebuild cycles, with kits, torque values and parts lists supplied for every service interval, so planning stays predictable.
What does the three start chuck thread change?
It engages and releases in roughly a third of the rotation needed by a single start thread. That shortens bit changes, reduces thread galling and keeps hands away from the chuck under the rig. It matters most on deep abrasive holes, where bit changes come more often than the schedule predicts and every minute at the collar is paid for.
What air supply and maintenance are recommended?
Plan a compressor that holds working pressure at the hammer at depth, and keep a steady oil feed matched to air volume. Watch cuttings return at the collar as the first sign of rising back pressure. Each hammer ships with a test record, torque values and a parts list so servicing stays a scheduled task.
Conclusion
The COP 44 GOLD Hammer answers a narrow but expensive problem: how to keep drilling metres per shift when the rock is abrasive, the ground collapses and the workshop is far away. A 110 mm to 130 mm range from one body, TD 40 shank with three thread options, a guided chuck casing variant for straight holes in broken ground, a hardened coated barrel and a rebuild programme behind it are the practical mechanics of that answer. For production drillers, the decision comes down to cost per metre — and that is a calculation we are happy to run with your own numbers.
Send us your hole diameter, rock type, rig and compressor specification, and we will return a matched hammer and bit recommendation, a rebuild plan and a quotation. You can also request the full catalogue or ask for a custom configuration for your casing programme. Contact our drilling team today to start the comparison.
