When it comes to rigging hardware—especially shackles—understanding the markings on the gear is critical. One of the most common sources of confusion? The word and markings for “ton.”
While it may seem straightforward, not all tons are the same, and if you’re not paying close attention, you could unintentionally exceed the safe working load.
What the Markings Mean
In the U.S., a short ton equals 2,000 pounds and is typically abbreviated as “T” on lifting hardware. However, many imported products—particularly those manufactured in Europe—use the metric ton, also called a tonne, which equals 2,204.6 pounds and is often marked with a script or lowercase “t.”
Here’s a quick comparison:
- US Short Ton (T) = 2,000 lbs
- Metric Ton (t or tonne) = 2,204.6 lbs
- British Long Ton (LT) = 2,240 lbs (less common today, mostly historical)
This subtle difference in markings can have major implications in the field.
Examples from Top Manufacturers
Here’s how the rated load capacity varies for a 1″ shackle depending on material and region. Add the complexity of “T” vs. “t,” and you can see how easily errors happen.
Crosby (U.S.)
- Carbon: 8 ½t = 18,739 lbs
- Alloy: 12 ½t = 27,558 lbs
- Note: Older Crosby shackles used “T” for short tons and a script “t” for metric.
Columbus McKinnon (U.S.)
- Carbon: 8 ½ T = 17,000 lbs
- Super Strong: 10 T = 20,000 lbs
- Alloy: 12 ½ T = 25,000 lbs
- Catalogs list both pounds and tons, but markings may vary.
Van Beest Green Pin (Netherlands)
- Grade 6: 8 ½ t = 18,739 lbs
- Grade 8 “Super Bow”: 12 ½ t = 27,558 lbs
- These are always metric-rated and color-coded for grade.
Why It Matters
If you mistake a metric rating for a U.S. ton—thinking a shackle marked “8 ½ t” is rated for 17,000 lbs instead of 18,739 lbs—you might miscalculate the limits of your rigging. A 10% difference might not seem like much, but in high-risk environments or multi-part lifts, that margin matters.
And while this kind of misunderstanding might not cause a failure on its own, it can absolutely contribute to one—especially when combined with other factors like:
- Misestimated load weights
- Worn or mismatched gear
- Environmental stressors (wind, angle, temperature)
- Inconsistent inspection or verification procedures
In practice, riggers should use this general rule of thumb:
- Use 2,000 lbs per ton when calculating shackle or hardware capacity
- Use 2,240 lbs per ton when estimating load weight
It’s a conservative approach—and in lifting, a little extra caution goes a long way.
Safety Standards to Know
For those responsible for inspections or compliance, under ASME B30.26 and related sections, shackles used in lifting must display:
- Manufacturer’s name or trademark
- Rated load
- Size
Additionally, the pin itself may also carry markings, such as the material grade, load rating, or manufacturer’s ID, which are especially important when verifying compatibility between shackle bodies and pins. If mismatched or unreadable, the pin may become the weak link—a major risk during lifting operations.
These markings are critical for confirming capacity and ensuring traceability back to the manufacturer. But in practice, field conditions can make markings difficult or even impossible to read—especially after exposure to dirt, corrosion, paint, or years of wear.
That’s why it’s essential to:
- Inspect shackles regularly for legible markings
- Remove hardware from service if identification is missing or unreadable
- Maintain supporting documentation (e.g., certificates, manufacturer specs) whenever possible
In specialized environments like offshore, nuclear, or custom lifting applications, shackles may also carry a serial number for individual tracking and load test records.
If your markings are gone, your confidence in capacity should be too.
Final Takeaway
Shackles may look alike, but the markings on them tell an important story—and that story includes which ton they’re using. With imported equipment common on job sites today, recognizing whether you’re working in short tons or metric tons isn’t just helpful—it’s essential for safe lifts.
When in doubt, verify the marking, check the manufacturer’s specs, and default to the more conservative number. Safety through education starts with the details—right down to the markings on your gear.
Need Help Interpreting or Inspecting Rigging Gear?
Crane Tech offers hands-on training that teaches your team how to read shackle markings, verify load ratings, and inspect rigging properly—so you can lift with confidence and stay compliant.
Call 1-800-290-0007 to speak with a training advisor, or visit www.cranetech.com to request a rigging gear inspection, schedule onsite rigging training, or enroll in an upcoming Qualified Rigger course.
Safety starts with knowing your gear. We’ll make sure your team does.