Crack repair by metal stitching is a proven, permanent, and cost-effective method to restore damaged cast iron and steel components without the need for welding. Moreover, this technique has become increasingly popular in industries such as marine, power plants, automotive, and heavy machinery because it effectively maintains the structural integrity of components. Even under high pressure and temperature, metal stitching offers reliable performance. As a result, it is now widely regarded as a preferred alternative to conventional welding methods.
In this article, we will explore how metal stitching services works, their benefits and applications, and why they are the preferred choice to traditional welding methods.

What Is Metal Stitching?
Metal stitching, also known as metal locking, is a cold repair technique used to fix cracks in cast iron, cast steel, and aluminum components. Unlike welding, metal stitching does not use heat, which prevents further stress or distortion in the damaged part.
How It Works:
- Drill and tap holes along the crack path.
- Insert special metal locks and pins to mechanically bond the fractured sections.
- Seal the crack completely to restore original strength and prevent leakage.

Why Choose Metal Stitching Over Welding?
Here’s a breakdown that adds practical context for real-life decisions:
Feature | Metal Stitching | Welding |
Heat Involved | No (cold process) | Yes (high heat) |
| Risk of Distortion | Minimal | High in cast iron components |
| Crack Propagation Risk | Low | High |
| Portability | High (onsite repairs possible) | Medium to Low |
| Suitability for Cast Iron | Excellent | Limited |

Applications of Metal Stitching
Metal stitching is used in a wide range of industries where precision and reliability are critical:
- Marine engines (like MAK, MAN, Wartsila, and Caterpillar)
- Diesel engine blocks
- Compressor casings
- Pumps and turbines
- Power plant cylinder heads
- Industrial gearboxes and housings
RA Power Solutions is one of the global leaders in onsite crankshaft grinding and crack repair by metal stitching, offering services in remote locations like Burkina Faso, Egypt, and Malaysia.
Advantages of Crack Repair by Metal Stitching
- Cost-effective: No need to replace expensive parts
- Time-saving: Repairs can be performed onsite
- Environmentally friendly: No heat or chemical pollutants
- Durable: Proven to last even under high-stress operations
- No disassembly required: In most cases, machinery stays in place
Crack repair by metal stitching is not just a temporary fix—it’s a permanent, engineering-approved solution that has stood the test of time. Whether you’re dealing with critical marine components or power plant machinery, choosing the right repair method can save you time, money, and stress.

Need expert crack repair at your location?
Contact RA Power Solutions today for onsite metal stitching services , metal locking, cracked cast iron, onsite crankshaft repairs, insitu crankshaft grinding and restore your machinery to full strength—without disassembly or downtime.
For more information, please email us at rajshahani@rapowersolutions.com, or info@rapowersolutions.com, or call us at +91 9582647131 or +91 9810012383.
FAQs
Technicians perform metal stitching as a cold mechanical process—with no heat or welding involved—by drilling, tapping, and inserting stitching pins and locks across a crack to “stitch” it closed. This method preserves the original material properties, prevents thermal distortion, and allows in-situ repairs, saving both time and cost compared to welding.
(i) Inspect and clean the crack.
(ii) Drill holes across the crack and connect them to fit metal “keys.”
(iii) Insert keys; peen them to lock in place.
(iv) Drill and tap along the crack line, then insert stitching studs.
(v) Grind flush the surface for a seamless finish
Yes. Metal stitching is ideal for large cast components (engine blocks, turbine casings, offshore equipment) and can be performed on-site without heat, minimizing downtime.
Absolutely. The method creates a pressure-tight, load-bearing mechanical joint, restoring original strength. It also dampens stress, acts as an expansion joint under thermal cycles, and avoids weakening the surrounding metal.
Used primarily on cast iron, steel, bronze, and aluminum, it’s perfect for cracked engine blocks, boiler casings, historic castings, pump housings, and more. It’s especially useful where welding is unsuitable due to heat sensitivity or misalignment risk.
