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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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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The problem of heavy leakage of oil was observed from the rear centre fuse casing. Our technicians visited the site and carried out the following jobs.

Action taken for repair of the damaged centre fuse, rear casing machine block by metal locking, metal stitching and metal surgery

• As mentioned above, heavy leakage of oil was observed from the casing.
• To check the cracks and weaknesses in the casting, the paint and red oxide were completely removed by a buffing process.
• Our engineer, qualified to do the MPI test, undertook the crack detection test of the completely damaged casing with a high-intensity Magnaflux torch and equipment which is designed by Magnaflux USA to detect even minor cracks which otherwise cannot be seen by the naked eye.
• The MPI test was done repeatedly in a critical area.
• Due to the complex profile, the crack detection was done even by the basic procedure of the dye penetrant method. A large portion of weak casting was observed, and multiple cracks of different lengths and profiles were also observed.
• The repair of the centre fuse rear casing machine block was undertaken by the metal locking and metal stitching process. The special alloy self-merging keys & locks were used to repair the cracks.
• The polishing by the special equipment was undertaken, and the original shape & profile of the casing was given.
• In order to ensure that there is no leakage of oil, a special chemical imported from our principles based in the UK was applied as per the procedure.

The Plant was recommissioned, and no leakage of oil was observed.

RA Power Solutions, with forty-five years of experience, undertakes the guarantee for all the jobs of crack repair and repair of damaged casting undertaken by us.

We have engineers with forty-five years of experience dedicated only to crack repair and repair of damaged casting. We specialize in the repair of heavy equipment used in power plants, oil & natural gas rigs and heavy engineering equipment. These services are offered all over the world.
All our technicians have a valid seaman book, and US VISA and can fly to any destination of the world in a short time.

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, 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 information, Metal Stitching and Metal Surgery process, crack casting repairing, Turbine casing crack repair on site, and crack repair damaged casting rectification Contact us at rajshahani@rapowersolutions.com, 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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In case of cracks repair in casting and repair of damaged heavy components, the consumables like locks, keys, master locks, etc, used must be of high tensile, again the job of metal stitching and metal locking is to be executed by experienced technicians.

RA Power Solutions has excellence in both areas. We import keys, locks, and master locks from Europe. These are sourced from companies with over a hundred years of experience. We have in-house technicians who specialize in crack repair by metal stitching and metal locking. They have been executing this work for more than forty-five years.

RA Power Solutions is the only company that can also execute the crack repair by metal stitching & metal locking onsite. The repairs are also possible while sailing the vessel.

The broad range of applications of crack repair by Metal Stitching/Metal Locking is as follows:

• Damaged engine bed plate, cylinder head, turbine casing, etc.
• Repair of heavily damaged industrial equipment.
• On-site repair of all the machinery installed on the vessel.
• Repair of damaged pump casings, gearboxes, and forging hammers.

We have been regularly executing metal stitching/ metal locking & repair services in 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 engine block stitching, repairing cast iron, 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.

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We have observed that, despite strictly following the maintenance schedule provided in the manufacturer’s manual, serious accidents still occur. These incidents often result in the casing of engines, compressors, or heavy engineering equipment breaking into pieces or developing multiple cracks.

RA Power Solutions recommended repair of damaged cast iron casting, Aluminium bronze components by metal lock and metal stitching process, having the following advantages:

• The main advantage of repairing of damaged or cracked engine block by the metal lock and metal stitching process is that it is a cold method of repair, and no heat is generated.
• No distortion in the profile or shape of the engine block or casing takes place. This is a common issue when crack repairs are carried out by welding, but our method avoids it.
• Metal lock and metal stitching process of crack repair can be performed on-site, avoiding the high cost associated with the disassembly of the equipment and transporting it to the designated workshop for repair. Metal stitching can be done in a limited space.
• It is proven that the crack repair of engine blocks, cast iron castings, and aluminium and bronze components restores their original strength. It is also successful for water-tight and gas-tight repairs.
• We have experienced that engine blocks repaired by the metal lock and metal stitching process do not lose their profile or shape. In most cases, engine blocks do not require any machining.

RA Power Solutions has successfully executed the repair of more than three thousand cracked, damaged, and rejected engine blocks, compressor casings, and heavy equipment across the globe. Our expertise has saved millions of dollars for the shipping and general industries.
We strongly recommend the repair of cracked or damaged components by the metal lock and metal stitching process.

The applications for the repair of cracks by metal stitching and the metal locking process are many and cover a broad range as follows:

• Repair of heavy equipment, large earth-moving machinery, and mining equipment.
• Repair of Alternator casing, turbine, Turbocharger, cylinder head, and all rotating equipment.
• Repair of cracked or damaged engine block metal locking.
• Bed Plate (crankcase repair)

RA Power Solutions has also undertaken successful crack repair in aluminium pistons and heavy-duty cylinder liners as a temporary measure. We provide guaranteed repair of all heavy engineering components manufactured from cast iron, aluminium, or bronze.

At RA Power, we have been regularly undertaking the repair of engine blocks, compressors, turbochargers, and all cast iron, bronze, and aluminium for the following makes of engines:-

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

We have been regularly executing the repairs in Argentina, Bahamas, Barbados, Bermuda, Bolivia, Brazil, Canada, Chile, Colombia, Costa Rica, Cuba, Dominican Republic, Ecuador, El Salvador, Guatemala, Guyana, Haiti, Honduras, Jamaica, Mexico, Nicaragua, Singapore, Dubai, etc

For more information on Engine Block Stitching, Turbine casing crack repair on site, metal locking, cast iron engine block metal lock, and engine block metal locking, contact us at rajshahani@rapowersolutions.com, info@rapowersolutions.com, or call us at +91 9582647131 or +91 9810012383.

FAQs:

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Crack Repair Process For Aluminium | Bronze Components:-

The damaged casting component is visually inspected by our experienced technicians.

It is necessary to remove the paint or red oxide from the crack area of the component. This is done by use of special chemicals.

The Crack Detection Test Of The Cracked Area Is Undertaken By Following Two Methods:-

• MPI test with high-intensity magnaflox torch.
• The crack test is done by in-house experienced technicians who are qualified as level 2 or level 3 technicians.
• Crack detection by conventional dye-penetrant test.

Planning and execution of crack repair by metal stitching and metal locking process:-

Once the area of crack is identified, we undertake the crack repair by metal stitching and metal locking process. This again is undertaken by our experienced technicians.

We have technicians available around the clock. Some of them have over 45 years of experience in undertaking crack repairs of engines, compressor pumps, heavy components, and badly damaged castings.

RA Power Solutions has undertaken hundreds of jobs of damaged casting repair by fixing the new casting piece in place of the damaged area.

Our success rate in repairing cracks and badly damaged castings using the metal lock and metal stitching technique is almost 100%. All crack repair jobs undertaken by us are guaranteed for satisfactory performance. The crack repair of engine components, compressors, and marine equipment can be undertaken on vessels even while sailing.

All technicians have valid Indian CDC and can board the vessel in a short time.

We have been regularly executing the repairs in Benin, Ghana, Burkina Faso, Ivory Coast, Nigeria, Mali, Liberia, Guinea, Niger, Cameroon, Equatorial Guinea, Sierra Leone, Gabon, Guinea-Bissau, Senegal, Gambia etc.

This blog is written by Mr. Raj Shahani (Managing Director of RA Power Solutions India Pvt. Ltd.).

Mr.Shahani is a highly experienced business leader with 45 years of rich experience in the field of Power, Heavy, and Shipping industries. He is a Technical Adviser to many shipping and heavy industries across the globe.

Mr. Shahani is one of the most enthusiastic professionals, and he has all the brilliance of an exemplary leader. He is an extremely effective coach and mentor of teams and is adept at providing leadership in a global, cross-cultural environment.

For more queries on Aluminium Piston Crack Repair, repairing a crack in casting, metal stitching process, crack repair techniques, and repair of a crack in cast iron casting contact us at rajshahani@rapowersolutions.com or info@rapowersolutions.com or call us at +91 9582647131 or +91 9810012383.

FAQs:

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