PRECISION MACHINE WORK GAUTENG
From line boring and surface grinding to precision turning and component reconditioning, every machining task at CMKT is carried out to exacting tolerances — because in the world of heavy diesel machinery, a fraction of a millimetre is the difference between an engine that performs and one that fails.
ENGINEERING MACHINING GAUTENG
Engineering machining is the process of cutting, shaping, grinding, boring, honing, and finishing metal components to precise dimensional tolerances. In the context of heavy diesel plant and equipment, machining is a critical step in any engine overhaul, component rebuild, or repair process. Without accurate machine work, even the highest-quality replacement parts will underperform, wear prematurely, or cause catastrophic failure.
For Gauteng’s construction, mining, earthmoving, and transport sectors, the stakes are especially high. Equipment downtime translates directly into lost revenue, missed project deadlines, and penalty clauses. CMKT Engineering combines deep diesel engine expertise with professional machine shop capability — ensuring that every component leaving the workshop has been machined to the tolerances specified by the original equipment manufacturer.
MACHINING SERVICES GAUTENG
Cylinder bores wear oval and taper over time, particularly in high-hour diesel engines used in construction and mining environments. Our bore machining process restores each cylinder to its correct geometry, ensuring uniform compression and extending the working life of the engine. Relevant for Caterpillar C4.4, C11, C15, C18; Cummins 6BT and QSL9; John Deere 4045 and 6068; ISUZU 4HK1, 6HK1, and 6BG1.
Crankshaft journals wear out of round under sustained load cycles typical of earthmoving plant, tipper trucks, and rollers. Regrinding main and rod journals to undersize restores correct journal geometry and surface finish, allowing undersized bearing shells to provide the correct oil film thickness. Covers Mitsubishi 6D24 and 6D16, Doosan DE12, Weichai WD10 and WD615, and Tata 3434 Novas units.
A warped or pitted cylinder head mating face leads to head gasket failure, coolant loss, and often catastrophic engine damage. Resurfacing removes material to restore a perfectly flat, smooth sealing surface. CMKT combines head resurfacing with pressure testing to identify cracks or porosity before the component returns to service — a step too often skipped elsewhere. Covers JCB 444 and 448, Deutz 2011 and 2012, and the broader Caterpillar range.
Line boring is required when main bearing bores or camshaft bores in an engine block have been damaged, worn out of alignment, or distorted by overheating. The process restores critical alignment that engine rotating assemblies depend on — essential for large displacement Caterpillar and Cummins engines in Gauteng’s mining and earthmoving sectors.
After boring, cylinder bores require honing to achieve the correct surface crosshatch pattern that allows piston rings to bed in and seal properly. CMKT uses correct honing equipment and processes to achieve the surface finish specified by each engine manufacturer — directly affecting oil consumption and compression retention over the engine’s service life.
Beyond engine-specific work, CMKT provides general precision machining for the production or repair of shafts, bushes, sleeves, flanges, spacers, and custom components. Where a standard replacement part is unavailable, the ability to machine a component to specification in-house dramatically reduces lead times and avoids costly equipment standing time — particularly valuable for older or imported plant where OEM parts supply is unreliable.
ENGINE FAMILIES WE MACHINE FOR
Machining tolerances, bore dimensions, journal sizes, and surface finish specifications differ across engine families. CMKT’s coverage spans the full spectrum of engines found in Gauteng’s heavy plant and transport fleets.
HOW IT WORKS
Every machining job begins with a thorough assessment. Cylinder bores measured for wear, taper, and ovality. Crankshaft journals measured for diameter, roundness, and surface condition. Cylinder heads checked for flatness and crack tested. This determines what operations are required, what oversize or undersize dimensions will be targeted, and whether the component is serviceable or beyond economic repair.
Before machining begins, components are thoroughly cleaned to remove carbon, sludge, scale, and corrosion. Machining contaminated components leads to rapid tool wear and can introduce debris into finished surfaces. A basic step that is sometimes neglected in less disciplined workshops.
Boring precedes honing. Crankshaft grinding is completed before journal measurement for bearing selection. Cylinder head resurfacing is completed before pressure testing. Each operation is performed to the dimension specified for the engine family concerned, verified with calibrated measuring equipment.
After machining, each component is re-measured and the final dimensions are recorded. This documentation forms part of the rebuild record and is available to the operator — allowing the correct replacement parts to be selected with confidence.
Machined components move directly into the engine rebuild or hydraulic reassembly process at CMKT. Because machining and rebuild are handled by the same team, the transition is seamless. The finished engine is then tested on the dynamometer before returning to service.
WHY CMKT ENGINEERING
Most machine shops in Gauteng are not also engine builders. CMKT is both. The engineers overseeing the machining work are the same specialists who will assemble and test the finished engine. This integration eliminates the risk of miscommunication between a separate machine shop and a separate rebuild workshop.
CMKT operates an engine dynamometer, which allows rebuilt engines to be run under controlled load conditions before reinstallation. This verifies that the machining work and assembly have produced an engine that meets its rated power and torque output — proven before it returns to work, not tested on site at the cost of the first job it is sent to do.
Heavy diesel engine machining tolerances are not guidelines — they are engineering requirements. A crankshaft journal ground 0.05 mm beyond specification will not form a correct oil film. CMKT measures, records, and verifies every critical dimension before a machined component is released for reassembly.
CMKT provides upfront assessments of the machining work required, explains what has been found and why it matters, and gives realistic timelines. No hidden costs added after the fact. Operators are kept informed throughout the process.
WHAT CLIENTS SAY
Our Cummins QSL9 on a SANY excavator seized up mid-project on a site in Gauteng. CMKT had it overhauled and back on the dynamometer within two weeks. The written report showed the engine performing to specification. We put it back into service with full confidence.
What impressed me most was that they offered us a replacement TLB while our machine was in for a full engine overhaul. No downtime on our roadworks contract. The machine came back fully tested and has given us no trouble since. Proper professionals.
We needed a 10 ton roller and a tipper truck for a roadworks contract in Limpopo and could not afford downtime on either unit. CMKT sorted both engine issues, tested the rebuilt units, and provided written reports before handover. We completed the contract on schedule.
We are based in Gauteng and serve clients across South Africa. If you need precision machining as part of an engine overhaul, a component rebuild, or a standalone machining operation, contact us to discuss your requirements.
Based outside these areas? WhatsApp us on +27 74 578 3032 and we will find a plan that works for you.
COMMON QUESTIONS
This is determined during the assessment and measurement phase. If a cylinder bore is within the maximum oversize that still allows a piston and ring set to seal correctly, machining and oversize pistons are the right choice. If a crankshaft journal is worn beyond the last available undersize, the shaft requires replacement. CMKT provides this assessment transparently — we explain what we found, what it means, and what the options are before any work proceeds.
Yes. If you have a component that requires machining as part of work being carried out elsewhere, or if you need a specific machining operation performed on a part you have sourced, CMKT can assess and machine it. Contact us to discuss the component and the required work.
Timelines vary depending on the scope of work and our workshop schedule. A cylinder head resurfacing and pressure test is a relatively quick operation. A full engine block including bore machining, line boring, and honing takes longer. We give realistic turnaround times during the assessment phase and communicate immediately if anything changes.
Where we have the dimensional specifications for the engine — either from manufacturer data or from measurement of the original worn component — we can machine to specification. For very old or obscure engines, we will tell you honestly if the work is within our capability. We do not guess on tolerances.
In most cases, yes — provided the engine block and major components are serviceable. A quality machine shop job combined with a thorough rebuild typically costs significantly less than a replacement engine, and in many cases the rebuilt engine will outlast a replacement if the root cause of the original failure is also addressed. CMKT helps operators understand the total cost comparison honestly.
Do not accept machining work that leaves your rebuild to chance. Contact CMKT Engineering and Projects for precision machine work carried out by the same team that rebuilds and dynamometer tests your engine.
CONTACT US
Contact our team to discuss your component, get a written quote, or arrange drop-off or collection.
