This process is trusted in industries like,

• Marine engines and crankcases
• Power plants and turbine casings
• Pump and compressor housings
• Heavy industrial machinery

Why Not Welding?

Welding large cast components often causes:

• Heat distortion
• Loss of strength due to metallurgical changes
• Crack expansion or new cracks
• Metal stitching avoids heat damage and preserves the original material strength.

How Keys & Locks Work in Metal Stitching

The core of Metal stitching involves installing metal keys (locks) and stitching pins into the crack

Step-by-Step Explanation:

Step 1: Drilling and Stop-Holing

• Small holes are drilled at both ends of the crack.
• This prevents the crack from spreading during the repair.

Step 2: Installing “Locks” (Metal Keys)

• A series of overlapping slots are machined along the length of the crack.
• Technicians insert precision-engineered metal locks (keys) into the slots

Purpose of Keys/Locks:

• They mechanically pull both sides of the crack tightly together.
• They distribute load and stress evenly across the repaired area.
• The locks exceed the strength of the original casting and restore structural integrity

Step 3: Installing Stitching Pins

• Holes are drilled perpendicular to the crack.
• Technicians screw stitching pins into the holes to fill and seal the crack,

Purpose of Stitching Pins:

• They hold the metal in compression.

• They make the repair pressure-tight, preventing leaks of oil, coolant, or gas.

Step 4: Surface Finishing

• The repaired area machined flush.
• After finishing, the repair hides the crack and restores the component to OEM tolerances.

Advantages of Using Keys & Locks in Metal Stitching:

Where This Method Is Used

Metal stitching with keys and locks is commonly used for:

• Cracked diesel engine blocks
• Turbine and pump casings
• Compressor housings
• Marine engine frames and bedplates
• Generator casings

Whether the crack is small or several feet long, the stitching process scales to the size and location of the damage.

Metal stitching using precision metal keys and stitching locks is a reliable, proven, and cost-effective cold repair technique. Unlike welding, it involves zero heat—meaning no distortion, no stress, and no change in material properties. This method restores the structural integrity of cracked cast components and saves industries from huge downtime, dismantling, and replacement costs.

And when it comes to execution, RA Power Solutions is one of the leading global experts in metal stitching and metal locking. With four decades of experience and thousands of successful repairs, we specialize in restoring engine blocks, turbine casings, cylinder liners, compressor housings, and other critical equipment right at the site — anywhere in the world.

For more information on metal stitching repair of engine block cracks, metal stitching crack repair, engine block crack repair, and Crack in Cylinder Liner, please email us at rajshahani@rapowersolutions.com or info@rapowersolutions.com, or call us at +91 9582647131 or +91 9810012383.

FAQs:

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What does “metal stitching” mean?

Metal stitching, also known as metal locking, uses a cold repair method to fix cracked or damaged cast iron parts effectively. This method doesn’t use heat; thus, there is no possibility of warping or changing the qualities of the material, unlike welding. Technicians often use it to fix cracks in engines, compressors, pumps, and other heavy machinery on the job site.

Why Pick Metal Locking to Fix Cast Iron Cracks?

No heat is needed; thus, it’s safe for castings that can’t handle heat.

• Strong and long-lasting—brings back original strength
• Repair on site—no need to take apart heavy machinery
•  Cost-Effective—saves money on time and logistics
• Our metal stitching crack repair works on everything from industrial engine blocks to marine cylinder heads, and it always gives great results, even in the most important situations.

The Best Metal Locking and Stitching Services

R A Power Solutions are experts at providing the best metal stitching and locking services for all kinds of cast iron and aluminum parts. We bring unrivaled accuracy and dependability right to your location with our modern tools, professional personnel, and worldwide reach.

The best services for fixing cracks

Need the best services for fixing cracks? Our team of professionals can take care of everything, from tiny hairline cracks to big structural faults. Our portable tools let us fix cracks on site in hard-to-reach places, which cuts down on downtime and boosts production.

Marine Engines and Power Plants are one of the top industries we serve.

Global Onsite Crack Repair Services

Our company specializes in onsite crack repair using state-of-the-art metal stitching and metal locking methods. Whether you are located in remote industrial zones or offshore marine locations, we come to you — minimizing equipment downtime and ensuring continuous operation.

Get in Touch Today

Don’t let a cracked casting halt your production or lead to costly replacements. Choose a proven, safe, and long-lasting solution with our crack repair by metal stitching services. Contact us today for the top metal stitching and metal locking services trusted by industries worldwide.

For more information on metal stitching repair of engine block cracks, engine block crack repair, and Crack in Cylinder Liner, please email us at rajshahani@rapowersolutions.com or info@rapowersolutions.com, or call us at +91 9582647131 or +91 9810012383.

FAQs

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In case of cracks in cylinder liners, pistons, or cylinder heads in heavy-duty engines, compressors, or turbines there is no need to reject them as now it is possible to repair the crack by a cold process called metal lock and metal stitching. This is a proven procedure of crack repair which has been followed for over 45 years.

We Undertake Crack Repair of the Following Components and Equipment

• Components Manufactured out of Cast Iron, Cast Steel, etc.
• Cylinder Liners, Cylinder Blocks, and Components Have Higher Hardness.
• Piston Manufactured Out of Aluminium
• Bronze Components

RA Power Solutions regularly undertakes repair of main engine components, which develop multiple cracks at different locations and lengths.

The following components were damaged and successfully repaired by the Metal Locking/Metal Stitching process

• In the case of a main engine, Cylinder liners developed multiple cracks from the outer diameter. The cylinder Liner length and inner diameter were 1500 MM and 600 MM respectively. We measured the cracks from 15 mm to 150 mm. RA Power Solutions Pvt Ltd repaired them successfully using the metal locking and metal stitching process. The repairs perform satisfactorily. The photographs below show the team carrying out the work.
• The engine block of the main engine also developed cracks in different locations. These cracks were repaired on board the vessel by Metal Locking and Metal Stitching Process. RA Power Solutions has more than 45 Years of experience in the repair of cracks, developed in the casting of heavy components.

For more information on metal stitching repair of engine block crack, engine block crack repair and Crack in Cylinder Liner please email us at rajshahani@rapowersolutions.com, or info@rapowersolutions.com, or call us at +91 9582647131 or +91 9810012383.

FAQs:

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The crack repair developed in high-casting components is executed onsite without dismantling the main equipment. RA Power Solutions has developed special alloy keys and locks that have almost ten times more strength than the original casting. Now it is possible to repair the cracks that develop in large, heavy-duty cylinder liners. The cracks repaired are mainly in the non-operational area of the cylinder liners. The repair of cracks in large cylinder liners has become popular, as in most cases, it is not possible to arrange the replacement of the cracked liners with new ones.

RA Power Solutions has saved a number of engines by repairing damaged cylinder liners. Our technicians repair cracks using our metal locking and metal stitching process

We regularly undertake the repair of engine blocks, compressors, and all cast iron, bronze, and aluminum components for the following engine makes:

• Akasaka
• Mitsubishi
• Daihatsu
• Yanmar
• Hanshin
• Kobe Mitsubishi
• Caterpillar
• Wartsila
• Deutz-KHD
• Volvo Penta SKL
• MAK
• Sulzer
• MAN B&W
• SKL
• MTU MAK
• Pielstick

We have been regularly providing metal stitching, metal locking, metal surgery, and repair services in Iraq, Iran, Dubai, Oman, Saudi Arabia, Singapore, Russia, Qatar, Abu Dhabi, Sharjah, Ajman, Umm Al-Quwain, Fujairah, Bahrain, Gambia, Kuwait, Antigua and Barbuda, Belize, Dominica, Dominican Republic, Malaysia, Indonesia, Madagascar, Vietnam, Grenada, Guyana, Haiti, Jamaica, Saint Kitts and Nevis, Saint Lucia, South Korea, Saint Vincent and the Grenadines, Trinidad, and Tobago, etc.

For more details on the repair of engine blocks, metal surgery, Crack Repair Of Cylinder Liners and MAN engine cylinder liners, please email us at rajshahani@rapowersolutions.com, or info@rapowersolutions.com, or call us at +91 9582647131 or +91 9810012383.

FAQs:

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Metal stitching and metal locking is a simple but proven process of repairing cracks in heavy components without following the wielding method, which generates excessive heat.

We observe that heavy components made of cast iron, bronze, cast steel, and aluminium often get damaged due to accidents. When the damaged portion of the casting breaks into pieces, replacement with a new component is usually not possible. A new part is expensive, takes time to manufacture, or belongs to obsolete equipment.

RA Power Solutions has experienced technicians who cut off the damaged portion of the component completely. They make a new casting of cast iron, cast steel, or aluminium as per the original component and bring it to the site. The team assembles the new casting properly and metal stitches it using the best quality metal keys and locks.

The photographs shown in this blog are of MAN main engine model SMIT MAN R666W (Main Engine Port Side) which met with a serious accident. In this case, we have successfully repaired the engine block, cylinder liner, and piston having multiple cracks, lengths measuring from 75 mm to 190 mm.

Advantages of repair of damage casting and crack by metal lock and metal stitching process.

This method of crack repair is the cheapest and can be executed in a short time. Onsite metal stitching repair is undertaken using our in-house trained technicians and consumables. Crack repair and repair of damage casting can be done in any part of the world and on board the vessel as our technicians have valid passports and seaman books. The process of crack repair by metal lock and metal stitching is approved throughout the world including Lloyds.

For more details regardingCrack repair in cast iron, crack repair of aluminium and cast iron repair by metal lock and metal stitching, please email us at rajshahani@rapowersolutions.com, or info@rapowersolutions.com, or call us at +91 9582647131 or +91 9810012383.

FAQs:

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The following are the main observations after the inspection of the cylinder liners and engine block:

The damaged cylinder liners and cylinder block were subjected to a crack detection test by MPI. RA Power Solutions uses a high-intensity Magna Flux torch to detect the cracks. Our technicians are also level three qualified to undertake the MPI test.

The details of the crack observed in the cylinder liners and cylinder block of the MAN main engine are as follows:

• Cylinder Liners: A crack having a length of approximately 150 mm was observed.
• In the case of the engine block, two numbers of cracks were observed.

1. A crack having a length of about 120 mm was observed in the cylinder liner sitting area on a fuel pump side.
2. A crack measuring about 130 mm was observed in the cylinder liner sitting area on the exhaust side.

The hardness of the cylinder liner was observed between 220-250 HB.

Repair undertaken by RA Power Solutions:

In the case of cylinder liners, the crack was repaired from the inside and from the outer diameter as well by a metal lock process. We used special alloy locks and keys to repair the crack.

The two cracks in the engine block liner sitting area were repaired by a metal lock. After repairs, the proper grinding and polishing were done on the crack area to maintain the specified tolerance.

The liners were assembled in the presence of our technicians. The engine was put into operation after the leak test. The performance of the engine after crack repair of cylinder liners and engine block is observed satisfactory.

We have successfully executed hundreds of jobs. These include damaged and cracked cylinder liners, pistons, engine blocks, and major components used in heavy equipment.

We offer our services across a wide range of countries, including Singapore, Dubai, Bahrain, Bangladesh, the United Arab Emirates (UAE), Indonesia, Gambia, Iraq, Iran, Qatar, Kuwait, Malaysia, Egypt, Nigeria, Mozambique, Saudi Arabia, Oman, Turkmenistan, Jordan, and Kazakhstan.

For more information regarding cylinder liners, engine block crack repair, and crack repair of MAN main engine, please contact us at rajshahani@rapowersolutions.com or info@rapowersolutions.com or call us at +91 9582647131 or +91 9810012383.

FAQs:

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Over time, cast iron heads can develop cracks, warping, or other damage due to overheating, stress, or wear. That’s where our expert team steps in. With over 45 years of experience, RA Power Solutions uses advanced metal stitching (metal locking) techniques to restore structural integrity — without the risks associated with welding.

Cast Iron Cylinder Head Repair

At RA Power Solutions, we fix broken engine parts called cylinder heads. Imagine a cylinder head like a cap on a bottle- it keeps everything inside safe. Sometimes, these cylinder heads, made of strong cast iron, can get damaged. That’s where we come in! Our experts at RA Power Solutions know how to mend and make them strong again. We use special tools and skills to fix the cracks and make the cylinder head work like new. So, if your engine’s cylinder head is not feeling well, bring it to us, and we make it healthy again.

Cast Iron Head Repair

Cast Iron Cylinder Head Repair by RA Power Solutions is a service that helps fix broken or damaged cast iron heads, and engine block liners of engines. If the head of your engine is cracked, chipped, or not working properly, RA Power Solutions can help make it as good as new. They use special techniques and skilled experts to mend the cast iron head, ensuring it works well, and your engine runs smoothly. Trust RA Power Solutions for reliable and effective cast iron head repairs by metal lock and metal stitching process.

Our Repair Process Includes:

• Thorough inspection and crack detection
• Cold repair using metal stitching, preserving original metallurgy
• Surface machining and pressure testing
• Reassembly and testing for performance assurance

For more information on Cast Iron Head Repair, Cylinder Head Repair and cylinder heads please email us at rajshahani@rapowersolutions.com or info@rapowersolutions.com, or call us at +91 9582647131 or +91 9810012383.

FAQs:

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All the repairs executed by us are on-site and without disassembly of the main equipment.

The procedure for metal locking and metal stitching of damaged components, as followed by RA Power Solutions, is as follows:

• A drilling fixture is attached at right angles to the crack. A hole pattern is drilled and repeated at intervals of 3/4 to 1-1/4 inches apart.
• The metal between each drilled hole is removed with the help of pneumatic tools to form a slot. The stock removed is narrower than the drilled hole, thus forming a serrated opening.
• We insert preformed locks of high-tensile alloy into the drilled slot. We peen the locks into the slots one on top of the other in an overlapping pattern. The casting thickness limits the depth, and we determine it by the required strength.
• After the locks are installed, holes are drilled and tapped, and threaded fasteners are applied. These are spotted along the entire length of the crack, overlapping one another. Their purpose, in part, is to fill the fracture with new metal and provide a pressure seal.
• The entire repair area is peened flush and finished ground. Painted if required.

The Metal Locking technique can be used to repair everything from casting faults. The broken machinery and improper machining to intricate items such as marine engines and gears. We can work on a wide array of materials, including work-hardened and heat-treated items.

RA Power Solutions extend Cast Iron Repair, metal stitching/ metal locking services all over the world including countries like Dubai, Oman, Saudi Arabia, Qatar, Abu Dhabi, Sharjah, Ajman, Umm Al-Quwain, and Fujairah, Bahrain, Kuwait, Iraq, Antigua and Barbuda, Belize, Dominica, Dominican Republic, Grenada, Guyana, Haiti, Jamaica, Saint Kitts and Nevis, Saint Lucia, Saint Vincent and the Grenadines, Trinidad, and Tobago, etc.

For more information on metal surgery, metal lock, and metal stitching, contact us at rajshahani@rapowersolutions.com or info@rapowersolutions.com or call us at +91 9582647131 or +91 9810012383.

FAQs:

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It was reported that due to an accident, the block of the CO2 compressor was badly damaged and required repair.

Action was taken by RA Power Solutions for the repair of CO2 compressor Block:

Considering the seriousness of the accident, a team of three technicians was deputed. On visual inspection, it was observed that the distance piece housing of the CO2 compressor was badly damaged into pieces. Multiple cracks of different profiles and lengths were also observed on the block of the compressor, the photograph is given below.

Action is Taken for the Metal Stitching & Repair of the Compressor Block

• The damaged area was thoroughly cleaned by the use of special chemicals.
• The paint and red oxide were completely removed.
• The MPI of the damaged area was undertaken by a qualified engineer with a high-intensity magnafux torch.
• Multiple cracks measuring in length ranging from 160 mm to 320 mm were observed.
• The large portion measuring about 8 inches by 6 inches was completely damaged, hence it was decided to completely remove the damaged portion and cast a new piece.
• The area of the housing which was not accessible by the MPI equipment. It was subject to dye penetrant test in order to check the cracks.
• The new piece of casting was placed on the main casing and was metal stitched, as can be seen in the photograph below. The photograph of the new casing piece is also given.
• The remaining cracks were repaired by a metal locking process.
• We used L20 locks and Cast Master pins with a length of 25 mm and a diameter of 8 mm for the metal locking process. The casing had serious damage and multiple cracks.

RA Power Solutions is the only company with forty-five years of experience. The Major repair is by metal locking and metal stitching process.

All our technicians have a valid seaman book, and US VISA . They can fly to any destination in the world in a short time.

Globally Business: RA Power Solutions

We have been regularly executing metal stitching, metal locking, metal surgery & repair services in Iraq, Iran, Dubai, Oman, Saudi Arabia, Qatar, Abu Dhabi, Sharjah, Ajman, Umm Al-Quwain, Fujairah, Bahrain, Kuwait, Antigua and Barbuda, Belize, Dominica, Dominican Republic, Malaysia, Indonesia, Madagascar, Vietnam, Grenada, Guyana, Haiti, Jamaica, Saint Kitts and Nevis, Saint Lucia, South Korea, Saint Vincent and the Grenadines, Trinidad, and Tobago, etc.

For more information on engine block stitching, Repair Of Damaged Compressor Block, and turbine casing crack repair on-site, contact us at rajshahani@rapowersolutions.com or info@rapowersolutions.com, or call us at +91 9582647131 or +91 9810012383.

FAQs:

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At RA Power Solutions, it is now possible to salvage and save what is otherwise a rejected component or a heavy piece of machinery.

The repair of damaged cast components by traditional welding process is not effective and reliable. In fact, in most cases, due to welding, more damage to the components is reported.

RA Power Solutions has forty-five years of experience in metal stitching, metal locking, and metal surgery

A company well known for extending all over the world for onsite repair of crankshaft and major components has the expertise to repair major and heavy components that are damaged due to accidents. Our clients are from cement plants, power plants, oil rigs, heavy engineering components, etc.

With the experience of forty-five years in the field of repair of damaged components by metal stitching, metal locking, and metal surgery, we are confident to say that the results obtained after repair are almost a hundred percent. All the jobs of metal stitching undertaken by us are guaranteed for satisfactory performance.

In case of an accident, we have the advantage over other companies. All our technicians are trained in metal stitching and metal locking processes. Training is done in our in-house training school based in IMT Manesar, Gurgaon. They have a valid CDC and a U.S. visa. They can fly on any plane or vessel all over the world. Equipment and consumables can be carried as accompanying baggage in a short time.

Thus reducing the breakdown time of a power plant or a vessel.

The main advantage of Cast Iron Repair by Metal Stitching:

• There is no requirement to dismantle the parts and send them to the workshop for repair.
• The metal stitching, metal locking, and metal surgery for crack repair of damaged casting are undertaken onsite. This avoids the high cost associated with disassembly and transportation.
• No heat is generated, which is associated with the welding process.
• Due to the cold process, no distortion of profile takes place, and in most cases, machining is not required.
• The repair area after metal stitching and metal locking is restored to its original strength with air and water fight repairs.
• In some cases, we apply special chemicals after repairs are completed.

We have been regularly executing metal stitching, metal locking, metal surgery & repair services in Iraq, Iran, Dubai, Oman, Saudi Arabia, Qatar, Abu Dhabi, Sharjah, Ajman, Umm Al-Quwain, Fujairah, Bahrain, Kuwait, Antigua and Barbuda, Belize, Dominica, Dominican Republic, Malaysia, Indonesia, Madagascar, Vietnam, Grenada, Guyana, Haiti, Jamaica, Saint Kitts and Nevis, Saint Lucia, South Korea, Saint Vincent and the Grenadines, Trinidad, and Tobago, etc.

For more information on Engine Block Stitching and turbine casing crack repair on site, Aluminum Crack Repair, contact us at rajshahani@rapowersolutions.com or info@rapowersolutions.com, or call us at +91 9582647131 or +91 9810012383.

FAQs:

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