If you’ve ever stood next to a drilling rig, you know the undercarriage is its unsung backbone. It’s the part that bears the full weight of the mast, the drill string, and all the heavy equipment perched on top, while rolling through uneven terrain, mud, rock, and sometimes extreme weather. As someone who’s spent 12 years building drilling rig undercarriages, I’ve seen firsthand what happens when these components don’t meet international standards: rigs break down mid-drill, workers get hurt, projects get delayed, and companies lose hundreds of thousands of dollars in downtime. Over the years, I’ve refined a process that ensures every undercarriage I supply meets the global standards that keep jobs safe and on track. Today, I’m sharing that process so you can trust that the undercarriage powering your next drilling project is built to last. Drilling Rig Undercarriage
First, it starts with knowing what international standards actually apply. A lot of folks new to drilling think standards are one-size-fits-all, but that’s not true. Different regions have different rules, and even within a single project, you might need to adhere to multiple standards. For example, if you’re working in the United States, OSHA (Occupational Safety and Health Administration) sets mandatory guidelines for heavy equipment structural integrity and load capacity. If you’re drilling offshore or in Europe, you’ll need to comply with API (American Petroleum Institute) Spec 4F, which specifically covers drilling and production equipment, or ISO 10425, the international standard for mobile drilling rigs. In parts of Asia and the Middle East, many operators combine API standards with local regulatory requirements, like those from Saudi Aramco or ExxonMobil’s project specifications for their fields. The biggest mistake I see new buyers make is assuming a “generic” undercarriage will check all boxes. Early in my career, I built an undercarriage for a client working in Kazakhstan that didn’t account for the country’s extreme winter temperatures, which cracked welds that would have held up in Texas’s milder climate. That mistake cost me a rework and a lost client, so now I start every project by mapping out every applicable standard before I touch a single piece of steel.
Next comes material selection—and this isn’t just about picking the strongest steel you can find. International standards specify exact material grades for every component of the undercarriage, from the track shoes to the main frame beams. For example, API Spec 4F requires that all structural steel used in drilling rig undercarriages meet minimum tensile strength and yield strength requirements, and many standards mandate impact testing for steels used in cold climates. I used to use a common grade of steel for track links that was cheaper, but it failed impact testing in temperatures below -20°F, which is standard in many Arctic drilling projects. Now I strictly follow the material specifications outlined in the relevant standards, and I keep third-party test reports for every batch of steel I source. I only work with suppliers that can provide mill test reports (MTRs) that confirm their steel meets the exact grade required, not just a vague “this is heavy steel” label. I also factor in corrosion resistance, which is a big one for drilling projects in swampy coastal areas or salt deserts. ISO 12944, the standard for corrosion protection of steel structures, specifies coating thickness and types for different environments, so I use hot-dip galvanizing or powder coating that meets those thickness requirements instead of cutting corners on paint to save money.
Then there’s the design phase, which is where most custom undercarriages get it right—or wrong. You can have the best steel in the world, but if the design doesn’t account for real-world drilling loads, it will fail. I always start with load calculations that adhere to the latest standards, but I don’t just plug numbers into a computer and call it a day. I collaborate with in-house engineers who have 20+ years of field experience, because computer models don’t account for the way a driver might accidentally drive a rig over a large rock, or how a drill string’s torque puts extra stress on the undercarriage. API Spec 4F requires that undercarriages undergo finite element analysis (FEA) to identify stress points, so I run FEA simulations for every design, and then I test those stress points by building a prototype and putting it through a load test that exceeds the standard’s requirements. For example, the standard might require testing the undercarriage to 125% of its maximum rated load, but I push it to 150% to make sure it can handle unexpected overloads that come with real drilling work. I also design for maintenance, which is something many standards touch on but don’t mandate explicitly. If a track pin wears out, you shouldn’t have to disassemble half the undercarriage to replace it. I design access points for grease fittings, track adjustments, and part replacements that make maintenance easier, which helps my clients keep their rigs compliant with OSHA’s lockout/tagout rules and other safety standards that require equipment to be easy to service.
Welding is another critical part of the process that’s often overlooked, but it’s where 90% of undercarriage failures start. International standards like AWS D1.1 (Structural Welding Code) and API Spec 4F have strict requirements for welders’ certifications, welding procedures, and weld inspection. I only hire welders who are certified to the level required for critical structural components, and I don’t let junior welders work on undercarriage main frames. Every welding procedure I use is tested and documented to ensure it produces consistent, strong welds that don’t have cracks or porosity. After welding, I don’t just do a visual inspection—I use non-destructive testing (NDT) methods like ultrasonic testing (UT) or magnetic particle testing (MPT) to check for hidden flaws that can cause welds to fail under load. Early in my business, I had a welder use an incorrect electrode that looked right on a visual check, but failed UT testing. That led to a recall of three undercarriages, and since then, I’ve made NDT a non-negotiable step in every part of the welding process. The standards I follow require a certain level of NDT for critical welds, and I go above that because I know a weld failure is not just a costly repair—it’s a safety risk for the crew working on the rig.
Once the undercarriage is built, it’s time for third-party certification, and this is a step I never skip. A lot of suppliers will tell you their undercarriage meets standards, but unless an independent, accredited third party has tested and verified it, that claim is just marketing. The process is straightforward: I hire a certified inspection company (like ABS or DNV, which are accredited to test against API and ISO standards) to test the finished undercarriage for load capacity, structural integrity, welding quality, and compliance with all relevant design specifications. They’ll run the undercarriage through a series of tests, including applying the maximum rated load, cycling the tracks to make sure they operate smoothly, and checking that all safety features (like emergency stop systems and load limit sensors) work as required. Once they sign off, they provide a certificate of compliance that clients can present to local regulatory bodies, project managers, and insurance companies. I’ve had clients show me certificates from suppliers that were self-issued, and those certificates were rejected by operators like Shell and Chevron because they know only third-party testing holds up. For international projects, the certificate of compliance is often required to get the rig into the country, so skipping this step can delay a project for weeks.
Quality control doesn’t end when the undercarriage leaves my workshop, either. International standards also require that manufacturers provide documentation of every component and test, so I keep a full file for every undercarriage that includes mill test reports for steel, welding procedure records, NDT reports, third-party inspection certificates, and operation and maintenance manuals that meet ISO requirements. I also offer post-delivery support, including on-site inspections for clients who need to recertify their undercarriages every few years, which is a requirement for many global operators. Last year, a client in Nigeria had their rig inspected by a third party, and they needed to provide updated maintenance records for their undercarriage. I was able to send them the full file within 24 hours, and they didn’t have any issues passing the inspection. That level of transparency is part of what ensures my clients trust that their undercarriages stay compliant throughout their lifecycle.
I know that for many drilling companies, choosing an undercarriage is about balancing cost and quality. I’m not going to lie—building an undercarriage that meets international standards takes more time and material than cutting corners, but the cost of a failure is far higher than the cost of a compliant undercarriage. A rig downtime day can cost $50,000 or more, and a single accident caused by an undercarriage failure can lead to fines, legal fees, and lost reputation. Over the years, I’ve built undercarriages for projects all over the world, and the ones that I’m most proud of are the ones that my clients tell me have run smoothly for years, without a single structural failure. That’s the standard I hold myself to, and that’s what I deliver to every client.
If you’re in the market for a drilling rig undercarriage and want to make sure it meets the international standards that keep your projects safe and on track, I’d be happy to walk you through my process and answer any questions you have. I work with small independent drilling companies and large global operators alike, and every project gets the same attention to detail and commitment to compliance that’s kept my business going for over a decade. Don’t risk a project delay or safety issue on an undercarriage that cuts corners on standards. Reach out to discuss your needs and get a custom solution that’s built to last.
Tracked Drill Rig Chassis References:
API Specification 4F, Specification for Drilling and Production Equipment
ISO 10425:2019, Mobile drilling rigs and drillers’ cabins – Specification and test methods
AWS D1.1/D1.1M:2020, Structural Welding Code – Steel
ISO 12944-5:2018, Paints and varnishes – Corrosion protection of steel structures by protective paint systems – Part 5: Protective paint systems
OSHA 29 CFR 1910, Occupational Safety and Health Standards for General Industry
Murphy Construction Machinery (Shandong) Co., Ltd.
Murphy Construction Machinery (Shandong) Co., Ltd. is one of the most professional drilling rig undercarriage manufacturers and suppliers in China, also supports customized service with low price. Please feel free to buy CE approved drilling rig undercarriage made in China here from our factory. For pricelist, contact us now.
Address: Room A3, Zone E, Yangqiao Industrial Park, Liuxing Street, High Tech Zone, Jining City, Shandong Province
E-mail: mefgcjx@126.com
WebSite: https://www.mefjx.com/
