Lifting Spreader Bars

Lifting Spreader Bars Buying Guide

Spreader bar or lifting beam: get the physics right first. The two get mixed up constantly, and the difference matters. A spreader bar hangs from two slings angled up to the crane hook, and those angled legs squeeze the bar end to end, loading it in compression. Structural members are efficient in compression, which is why a true spreader is light and affordable for its rating. A lifting beam hangs from a single bail at its center with the load hung from points along its length, so the beam is loaded in bending, which takes more steel for the same rating but needs almost no height above the beam. Pick the spreader when the load is wide, the lift points want a straight vertical pull, and there is hook height to spare for the top rigging. Pick the lifting beam when the ceiling is low or the pick points are uneven or off center. Tandemloc's AL50 series is a combination unit that rigs either way, one beam for a shop that faces both problems.

Size to the spread first, then the capacity. The bar's job is to put a vertical sling directly over each lift point, so the spread, the distance between end fittings, has to match the load. If your loads vary, adjustable beats guessing: the Tandemloc AT14 telescopic beams pin-adjust from 48 out to 240 inches, the adjustable kits run 51 inches to 19 feet at 28,000 to 100,000 lb, and Star Industries builds 6 and 12 ft fixed crane bars plus 8 to 12 and 12 to 20 ft adjustable models at 5,000 lb. One habit to build: confirm the rating at the spread you will actually use, not the headline number. On the modular end cap systems each pipe size carries its rating only out to a stated maximum span.

The top rigging is part of the machine. A spreader only sees clean compression when the top slings run at the angle it was designed for, so treat the top rigging as part of the lifter, not an accessory. Tandemloc sells the AT14 with and without its matched top sling assembly for exactly this reason: the matched sling sets the geometry the beam was rated at. If you rig your own, hold the beam maker's specified angle and keep the legs symmetrical. Budget headroom honestly, too. The angled top slings add several feet between the hook and the beam, which is the classic reason a spreader that fits the load will not fit the building. Measure hook height at the working position before you order.

Build your own beam with end caps. The end cap system is the budget path to owning several beams. A pair of Tandemloc caps fits standard pipe, steel caps on steel pipe you cut and drill to length or buy prepared, aluminum caps on Schedule 80 6061-T6 aluminum pipe, and the assembly becomes a rated spreader. Capacity rides on pipe size and span: the steel range pairs pipe from 3 to 6 inches with ratings from 14 to over 50 tons and spans out to 36 ft. One set of caps plus a few lengths of pipe covers what a whole rack of fixed bars otherwise would, which is why the caps start around $600 while comparable fixed beams run well into four figures.

Put the hook over the center of gravity. A lift is stable when the crane hook sits directly over the load's center of gravity. With a symmetric spreader and equal top slings that means a centered CG; if the CG sits off center, the bar tips until the hook finds it, and one sling quietly takes far more than its share. For repeat lifts of off-center loads, use a bar with multiple attachment points, like Tandemloc's forklift spreader with multiple padeyes, so the pick can shift to sit over the CG, or rig unequal top legs to a plan from a qualified person. Container work has a dedicated answer in the Tandemloc ISO container spreader beam, which locks into the corner castings and keeps the pull vertical at each casting.

ASME B30.20, markings, and inspection. Spreader bars and lifting beams are below-the-hook lifting devices, governed by ASME B30.20 with design rules in ASME BTH-1. In practice that means three things. First, the device must be marked, manufacturer, serial number, and rated load at minimum, and the markings have to stay legible. Second, the bar's own weight counts against your crane or hoist capacity, which starts to matter as beams get heavy. Third, inspection follows the same rhythm as the rest of your rigging: frequent visual checks in service plus documented periodic inspections, on intervals that tighten as service gets heavier. Tandemloc ships each lifter proof tested to 125% of rated load with certification; file it next to your periodic records.