Crack Repair Using Metal Stitching and Metal Locking | RA Power Solutions

Cracks in cast iron and other metal components can lead to significant operational challenges in the power generation, marine, manufacturing, and heavy engineering industries. Traditional repair methods, like welding, often introduce thermal stress, weakening the material over time. With over 44 years of experience, RA Power Solutions specializes in metal stitching and metal locking, two highly effective cold repair techniques that restore the integrity of cracked components without causing additional damage.

What is Metal Stitching?

Metal stitching is a cold repair method for mending cracks in cast iron, aluminum, and other metals without welding. It involves drilling precise holes along the crack, inserting metal stitching pins, and locking the pieces together to restore the component’s original strength. This technique is ideal for engine blocks, turbine casings, compressors, and other high-stress industrial machinery parts.

Metal stitching and Metal locking
Metal stitching and Metal locking

What is Metal Locking?

Metal locking is a reinforcement method used alongside metal stitching. Custom-designed locks are inserted into the stitched area to provide additional support, preventing further crack progression and ensuring a long-lasting repair. This method enhances the durability of the repaired component, making it as strong as or even stronger than the original structure.

metal locking
Metal locking

Why Choose Metal Stitching and Metal Locking?

Compared to traditional welding, metal stitching and locking offer several advantages:

  1. Cold Repair Process: No heat is applied, preventing material distortion, stress buildup, and further cracking.
  2. Onsite Repairs: No need to transport heavy machinery; repairs can be performed at the client’s location, reducing downtime.
  3. Retains Original Strength: Unlike welding, which can weaken cast iron, metal stitching and metal locking maintain or even improve the structural integrity.
  4. Cost-Effective: Eliminates the need for expensive replacements and reduces overall maintenance costs.

Benefits of Metal Stitching and Metal Locking

RA Power Solutions has successfully performed repairs for various industries, including:

  • Marine Industry: Repairs on ship engine blocks and connecting rods to avoid costly replacements.
  • Power Plants: Restoration of turbine casings, generators, and compressors to maintain efficiency.
  • Manufacturing Plants: Fixing cracks in heavy-duty machines and industrial equipment.

RA Power Solutions provides metal stitching and metal locking services in countries across Asia, the Middle East, Europe, Africa, and the Americas, including India, UAE, USA, UK, Saudi Arabia, Germany, Singapore, and Australia. With a strong global presence, the company offers onsite repair solutions for industries like marine, power plants, and heavy engineering, helping clients avoid costly replacements and downtime. Their expertise extends to Malaysia, Indonesia, Qatar, Oman, Kuwait, Bangladesh, Sri Lanka, the Philippines, Vietnam, Nigeria, Brazil, Germany, Singapore, Malaysia, Indonesia, and South Africa, ensuring reliable crack repair services worldwide.

Crack repair by metal stitching
Crack repair by metal stitching

For more information regarding repair cast iron, repair crack cast iron, or cast iron repaircrack repair by metal stitching and metal locking, contact us at rajshahani@rapowersolutions.com or info@rapowersolutions.com, or call us at +91 9582647131 or +91 9810012383.




Cracks in cast iron and other metal components can lead to significant operational challenges in the power generation, marine, manufacturing, and heavy engineering industries. Traditional repair methods, like welding, often introduce thermal stress, weakening the material over time. With over 44 years of experience, RA Power Solutions specializes in metal stitching and metal locking, two … Continue reading “Crack Repair Using Metal Stitching and Metal Locking | RA Power Solutions”

Cast Iron Crack Repair | Metal Stitching Crack Repair | Repairing Crack Cast Iron by Metal Stitching & Metal Lock – RA Power Solutions

Metal stitching and metal lock process of repairing a crack casting or complete damage of cast iron parts of large equipments is considered to be the ultimate solution of successful repair. The repair of cracks and repair of damaged casting by metal locking or metal stitching process is simple and most effective method of repairing cracks in cast iron and aluminium components. The process is entirely a cold process and no heat is generated like in process of crack repair or damage casting repair by conventional and old method of welding.

RA Power Solutions having experience of more than forty years in providing cold metal stitching cast iron, onsite repair, and metal locking services for high-capacity main engine, auxiliary engine, and large and heavy rotary equipment installed on vessel or in industry. We extend crack repair services through our experienced and factory-trained technicians.

The following are the main features of crack repair undertaken by RA Power Solutions:

  • Detection of crack in cast iron or aluminium components: It is important that proper procedure is followed by experienced technicians to detect the exact location, length, and intensity of the crack. We have experience that in most of cases, no procedure is followed to identify the intensity of the crack which results to the failure of the component even after the repair by metal lock and metal stitching.
  • RA Power Solutions possess latest equipment to undertake MPI (Magnetic Particle Inspection) by qualified level 2 technicians, and we give great importance to the detection process of the cracks. The unattended cracks can grow and result to the failure of the component.
  • Once the number of cracks, length of crack, intensity, and depth of crack is determined and identified the repairs are undertaken by the metal stitching and metal lock process.

Some of the advantages of repairing cracks by metal stitching metal lock are mentioned below:

  • It is our experience that the majority of repairs of damaged components or cracks can be repaired on site with no requirement of dismantling the equipment. This reduces the downtime and of course the cost involved in dismantling and transportation of the equipment.
  • Repair of cracks and repair of damaged gray iron casting or aluminium by metal stitching and metal lock process does not generate any heat. Thus, it does not require any machining process. No alignment or profile is damaged.
  • In the case of diesel engines, compressors, or rotatory equipment majority of the parts are of aluminum or cast iron. It is possible to repair them by metal stitching metal lock process. Hence, no need of replacement of parts. It reduces cost of maintenance considerably.
  • Repair of crack by metal stitching metal lock process absorbs compression stresses which is of great advantage.

RA Power Solutions have been extending metal stitching, metal lock, and metal surgery services all over the world. The technicians with years of experience come to your site or on board the vessel for repairs. Our technicians possess Indian CDC and can board the vessel and sail in shortest possible time. Thousands of jobs of serious damage have been repaired successfully by RA Power Solutions.

For more information about cold metal stitching, metal stitching crack repair, cast iron metal stitching, repair of crack in cast iron casting, repairing cast iron metal lock, and metal locking services, please email us at rajshahani@rapowersolutions.com or info@rapowersolutions.com, or call us at +91 9582647131 or +91 9810012383.

Metal stitching and metal lock process of repairing a crack casting or complete damage of cast iron parts of large equipments is considered to be the ultimate solution of successful repair. The repair of cracks and repair of damaged casting by metal locking or metal stitching process is simple and most effective method of repairing … Continue reading “Cast Iron Crack Repair | Metal Stitching Crack Repair | Repairing Crack Cast Iron by Metal Stitching & Metal Lock – RA Power Solutions”

Metal Stitching and Thread Repair Inserts – RA Power Solutions

One of our clients informed RA Power Solutions about damage to the cam case cover of a MAN diesel engine on board a vessel sailing near China. After reviewing the details and photographs, we observed that the cam case cover had broken into pieces. We also found that the threads on the engine body and the dowel pin were damaged.

Cracked Housing of Engine Block
Cracked Housing of Engine Block
Broken Area
Broken Area
Damaged Upper Threads
Damaged Upper Threads

RA Power Solutions Executes Onboard Repair of Engine Block and Cam Case Cover Sitting Area:

RA Power Solutions deputed their team of technicians on board the vessel, and they executed the repair of engine block, cam case cover sitting area by the following procedure:

  • The broken bolt which remained inside the thread hole was drilled out.
  • The damaged threads on cam cover sitting area on entablature was removed by drilling new blind holes, suiting the new M12 Helicoil thread inserts.
  • Re-tap holes for the new M12 Helicoil thread inserts was done carefully.
  • New M12 Helicoil thread inserts were installed in the engine frame/ entablature.
  • The 2 guide pins for the roller guide housing were removed, taking due precaution.
  • Technicians installed a new roller guide housing using correct M12 hexagon bolts. They also included the newly introduced 10 mm washers.
  • Technicians completed the final alignment of the roller guide housing. They then tightened the bolts using the correct tightening torque.
  • Technicians drilled two ø8 mm guide pinholes in both the roller guide housing and the engine frame. Afterwards, they installed new guide pins.
repair of Threads on Engine Block Under Process
repair of Threads on Engine Block Under Process
Repair of Thread Hole by Metal Stitching
Repair of Thread Hole by Metal Stitching

What Is Metal Stitching?

Metal stitching, also known as metal locking, uses a cold repair technique to fix cracked or broken cast components. This method eliminates the need for welding. The process restores original strength and ensures pressure-tight sealing through mechanical locking of stitching pins and studs.

Advantages of Metal Stitching Over Welding:

  • No heat means no distortion, warping, or residual stress
  • Maintains alignment and surface profile of the original cast
  • Suitable for cast iron, steel, aluminum, and other alloys
  • Creates permanent, pressure- and liquid-tight repairs
  • Enables on-site repairs with minimal disassembly
  • Often stronger than the original material
Damaged Thread Hole Under Metal Stitching and Metal Locking
Damaged Thread Hole Under Metal Stitching and Metal Locking
Metal Stitching of Bottom Area of Threaded Hole to Give Extra Strength
Metal Stitching of Bottom Area of Threaded Hole to Give Extra Strength

Our Process at RA Power Solutions:

  • Damage Inspection & Assessment: Document cracks and thread damage
  • Thread Repair via Stitching & Inserts: Use stitching keys and Helicoil/insert methods
  • Post-Repair Finishing: Grind and align to restore original surface
  • Testing & Validation: Conduct pressure or stress tests to ensure integrity.

With decades of experience and advanced cold-repair tools, RA Power Solutions delivers efficient and durable repairs without removing heavy castings.

Cam Cover Sitting Area of Engine Block After Repair
Cam Cover Sitting Area of Engine Block After Repair

For more on metal stitching and metal locking, metal stitching of engine block contact us today email us at rajshahani@rapowersolutions.com, info@rapowersolutions.com, or call us at +91 9582647131 or +91 9810012383.

FAQs:

1. What is metal stitching, and how does it work?

Metal stitching, also known as cold metal locking, is a mechanical repair process used to fix cracks in cast iron or cast steel components. It involves inserting stitching pins and locks to restore structural integrity—without welding or heat.

2. When should I use thread repair inserts like Helicoil?

You should use thread repair inserts when original threads in an engine block, casing, or housing become stripped, worn out, or damaged. Helicoils restore the thread’s strength and allow secure fastening, even under high torque.

3. Is metal stitching better than welding for cast iron repair?

Yes. For cast iron and other brittle materials, metal stitching is safer and more reliable than welding. It avoids heat distortion, cracking, and structural weakening, which are common risks with welded repairs.

4. Can RA Power Solutions perform these repairs on-site?

Absolutely. RA Power Solutions specializes in on-site metal stitching and thread repair, including work on marine vessels, power plants, offshore rigs, and remote industrial sites—without the need to remove the equipment.

5. What components can be repaired using metal stitching and thread inserts?

These techniques can repair engine blocks, cylinder heads, gearboxes, cam case covers, pump casings, compressors, and more. These methods can typically restore any cracked or damaged cast iron or steel component.

One of our clients informed RA Power Solutions about damage to the cam case cover of a MAN diesel engine on board a vessel sailing near China. After reviewing the details and photographs, we observed that the cam case cover had broken into pieces. We also found that the threads on the engine body and … Continue reading “Metal Stitching and Thread Repair Inserts – RA Power Solutions”

Cast Iron Crack Repair with Metal Stitching & Metal Locking

Experts highly recommend metal stitching and metal locking for repairing cracks in cast iron. Industries around the world use this cold repair technique because it delivers reliable and effective results when restoring cast iron components.

Broken cast iron pieces can also be replaced by a new piece of casting undertaking metal locking. This technology is as old as the introduction of cast iron casting in industry.

Insertion of Casting Piece in Engine Block
Insertion of Casting Piece in Engine Block
Metal Stitching of Jenbacher Engine Block in Process
Metal Stitching of Jenbacher Engine Block in Process

Metal keys and metal locks are used to undertake crack repair in cast iron casting.

Metal keys and Metal Locks are used in Metal Stitching/Locking Process

RA Power Solutions Pvt. Ltd. has a team of trained technicians who carry out metal stitching of broken or cracked castings directly onsite. They bring all necessary tools, consumables, and, if needed, a replacement casting to the site. The team repairs the crack onsite and avoids any need to disassemble or transport the equipment.

Metal Stitching Done in Broken Area of Generator
Metal Stitching Done in Broken Area of Generator

Tests and experience show that metal stitching repairs can strengthen cracked castings. The repaired section often becomes even more durable after the process. We execute crack repairs on board the vessel, in power plants all over the world.

Why Choose Cold Repair Over Welding?

Traditional welding uses heat to damage alignment, change grain structure, and weaken cast iron components. Cold repair procedures such as metal stitching and locking maintain the original material integrity. This results in stress-free, distortion-free, and high-strength solutions.

What Is Metal Stitching & Metal Locking?

Metal stitching is a cold bolt-locking process that includes drilling precise holes along a crack and inserting metal “keys” and studs into a dovetailed pattern. These studs bite into one another, tightening the crack and restoring structural rigidity.
Metal locking supports stitched joints with custom-shaped metal inserts, inhibiting additional proliferation and boosting long-term endurance.

We extend metal stitching services all over the world, including countries like Madagascar, Oman, Qatar, Philippines, Bahrain, Srilanka, Bangladesh, Myanmar, Turkey, Nigeria, Greece, Saudi Arabia, UK, Dubai, Singapore, Malta, and Cyprus, etc.

For more information on crack repair by metal stitching, Cast Iron Crack Repair, cast iron stitching, repair cast iron, cast iron metal stitching services, crack repair in cast iron, and repairing cast iron metal lock, contact us at rajshahani@rapowersolutions.com or info@rapowersolutions.com or call us at +91 9582647131, or +91 9810012383.

FAQs:

1. What is metal stitching in cast iron repair?

Metal stitching is a cold repair process used to restore cracked or damaged cast iron components. It involves inserting special metal keys and locking pins across the crack to mechanically join and seal it—without using heat or welding.

2. How is metal locking different from metal stitching?

While both methods are used together, metal locking adds reinforcement by embedding strong metal locks or inserts that cross the crack. These locks increase structural integrity and prevent further crack propagation.

3. Why is metal stitching better than welding for cast iron?

Welding applies heat that can distort the casting and cause new cracks due to thermal stress. In contrast, metal stitching is a cold process, meaning there’s no heat, no distortion, and the original metallurgical properties remain intact.

Experts highly recommend metal stitching and metal locking for repairing cracks in cast iron. Industries around the world use this cold repair technique because it delivers reliable and effective results when restoring cast iron components. Broken cast iron pieces can also be replaced by a new piece of casting undertaking metal locking. This technology is … Continue reading “Cast Iron Crack Repair with Metal Stitching & Metal Locking”