--- title: "Watch Machinists Stitch a Cracked Engine Block Together Without a Single Weld" description: "At the risk of sounding like a cynical, middle-aged guy from the East Coast, it's rare that I stumble across something on social media that I haven't seen before. I can still play the AOL dial-up squeal in my head…" date: "2025-03-25" modified: "2025-03-25" authors: - name: "Byron Hurd" job_title: "Editor" link: "https://www.thedrive.com/authors/byron-hurd" url: "https://www.thedrive.com/news/watch-machinists-stitch-a-cracked-engine-block-together-without-a-single-weld" categories: - "Car Tech" - "Manufacturing" - "News" - "Watch This" --- # Watch Machinists Stitch a Cracked Engine Block Together Without a Single Weld ![]() *\Syracuse Crank & Machine , LLC\* At the risk of sounding like a cynical, middle-aged guy from the East Coast, it's rare that I stumble across something on social media that I haven't seen before. I can still play the AOL dial-up squeal in my head from memory, OK? I've seen some Internet. So when [Caleb]() sent me [this reel of Syracuse Crank & Machine stitching (yes, stitching) an old cracked industrial engine block back together](), I was genuinely curious. It led me down a brief Internet rabbit hole, as such things tend to do, so allow me to introduce you to a metal casting repair process known as Precision Metal Stitching, aka [Lock-N-Stitch](). It's a proprietary system designed as a substitute for situations where welding is either impractical or has already proven ineffective. Rather than repairing a crack or blowout through the application of heat or friction, new metal is introduced in the form of pins. These pins are essentially small bolts with extra-thick heads that are designed to pull the two sides of a cracked casting together. Once installed, those thick heads can be ground flush for a clean finish. To get the threaded pins into the block, the machinist must first bore holes along the crack in a criss-cross pattern to ensure that the pins apply torque to close the metal gap. Then, the holes are tapped to accept the threaded pins and they're treated with a thread sealant. Once the pins are inserted and tightened, the resulting repair should be robust enough to hold compression in an engine block, for example. I hesitate to call it "good as new," but the results certainly speak for themselves. > [View this post on Instagram]() > [A post shared by Syracuse Crank & Machine (@syracusecrank)]() ![]() *Syracuse Crank & Machine , LLC* ![]() *Syracuse Crank & Machine , LLC* ![]() *Syracuse Crank & Machine , LLC* "The repaired, metal-stitched area is gas- and liquid-tight to create a pressure-tight repair," the company's website says. "In addition, metal stitching dampens and absorbs compression stresses. It also spreads tensile strains and distributes the load away from the original failure point, while maintaining the alignment of the original surfaces." As you can see above, once the pins have been ground down, the result looks eerily similar to a weld—and remarkably clean for the result of a process that seems so... primitive. The company says the technique is employed chiefly on cast iron but can be used on ductile iron, steel, aluminum and bronze castings too. Pretty cool, eh? *Got a tip? Send it in: tips@thedrive.com* ## Author Byron is an editor at The Drive with a keen eye for infrastructure, sales and regulatory stories. He brings a light, punchy style to all of his content, believing that there's plenty out there to be laughed at—himself included. Born and raised in Maryland but now based just a stone's throw from Detroit, Byron is an auto enthusiast and generalist who enjoys building and tinkering with things of all kinds, from cars, computers and digital cityscapes, to the new garage that will soon house his fleet (a CT4-V Blackwing, a JK Wrangler and an NA Miata). Inspired by an early love of rollercoasters, Byron quickly caught the high-performance driving itch. He's been tracking and auto-crossing his cars since 2007. In his downtime, Byron enjoys reading, playing city builders, and studying the history of the Motor City. ### Author social links [Bluesky]() [Instagram]() [LinkedIn]()