Pinces de serrage

Which clamp do I need to hang a light on truss?

Any clamp rated for the outside diameter of your truss's chord tube and for the weight of the fixture, because a clamp sizes to the tube and not to the truss. Most of this collection is built for the 1.97 in (50 mm) tube: Global Truss lists its 1.89 to 2.01 in (48 to 51 mm) clamps as compatible with F31, F32, F33, F34, DT34P and DT44P, Galaxy Stage lists its half coupler for GS34, GS12 and GS20, and CHAUVET rates the CLP-15 for 2 in (50 mm) truss. That is why one clamp size covers the whole 11.42 in (290 mm) box truss family, and why "which truss do I have" is the wrong question to start with. Two things in here are not fixture hangers at all: swivel and dual clamps join tube to tube, and scrim clamps mostly grip a stand upright to give truss scrim a stretch point.

What is the difference between a half coupler, an O-clamp and a C-clamp?

A half coupler wraps one tube in a closed jaw and hangs the fixture from a threaded stud below it, an O-clamp is a one-piece ring that closes 360 degrees around the tube on a single bolt and wing nut so it cannot be lifted off the chord, and a C-clamp is an open hook jaw pinched shut by one screw rather than closing all the way around. Half coupler is the same part people call a cheeseborough or cheeseboro. A G-clamp is a deeper throat screw clamp with a wider jaw range than a C-clamp. Shape does not tell you the rating: ADJ publishes 28 lb (13 kg) for its O-CLAMP/1.5 and 50 kg (110 lb) for its C-CLAMP, while ProX publishes 660 lb (300 kg) for the T-C4SH, which is also an O-clamp.

What is a trigger clamp, and is it worth paying more for one?

A trigger clamp is a hook body with a sprung trigger or self-locking latch that takes the fixture's weight one-handed before you tighten anything, and it earns the extra money if you hang and strike a lot of fixtures from a ladder or a lift. Global Truss publishes 550 lb (250 kg) for both its TRIGGER CLAMP and its QUICK RIG CLAMP, each on 1.89 to 2.01 in (48 to 51 mm) tube with an M10 x 30 mm fixture bolt, and Elation publishes the same 550 lb (250 kg) for its QUICK RIG CLAMP. Hook and snap clamps are the same idea without the sprung trigger, dropped over the chord and then locked: the Global Truss SNAP CLAMP is published at 440 lb (200 kg). If a rig goes up once and stays up, a plain half coupler does the same job for less.

When do I need an eye clamp instead of a plain half coupler?

When the drop attaches with a shackle, safety cable or chain rather than a bolt through the fixture yoke, because an eye clamp replaces the threaded stud with a welded eye nut. The number that decides whether your shackle fits is the eye nut inside diameter, and Global Truss publishes it: 0.75 in (19 mm) on the JR EYE CLAMP, 0.94 in (24 mm) on the EYE CLAMP and 1.14 in (29 mm) on the X-PRO EYE CLAMP/M12. Read the rating wording carefully as well, because Global Truss labels eye clamps with a maximum static load capacity, 440 lb (200 kg) on the EYE CLAMP and 165 lb (75 kg) on the JR EYE CLAMP, which is a different phrase from the maximum load capacity printed on its plain clamps. Odyssey builds the same idea as a half coupler with an eye bolt in place of the threaded stud. Pair either one with a safety cable.

What is a swivel clamp or a dual coupler for?

Both join tube to tube rather than hanging a fixture: a swivel clamp puts two jaws on a rotating knuckle so two tubes can cross at any angle, and a dual coupler holds two fixed jaws in one body so two tubes sit side by side in the same plane. Use a swivel to tie truss to truss or truss to a pipe, to brace a leg, or to carry a tube off an existing run. Global Truss publishes 1,650 lb (750 kg) for the X-PRO SWIVEL CLAMP and 440 lb (200 kg) for the narrower SWIVEL CLAMP/N, both on 1.89 to 2.01 in (48 to 51 mm) tube, and CHAUVET Professional publishes 1,650 lb (750 kg) for the CTC-50SCL. The dual couplers here are Odyssey and ProX parts; the Global Truss items titled dual clamp are swivels. For the conical couplers, tapered pins and spacers that join truss segments end to end, see Couplers.

Why does a narrow clamp hold less than a wide one?

Because a narrower body grips less of the tube, so the same manufacturer publishes a lower number for it, and you are trading rating for clearance between the cross braces. Global Truss sells three matched pairs, and in each one the wide 1.97 in (50 mm) body is rated above the 1.18 in (30 mm) narrow body.

Pick narrow when a fixture has to sit close to a node or another clamp, wide when the fixture is heavy. Check the thread too: the X-PRO family takes an M12 x 40 mm fixture bolt where most of the Global Truss line takes M10, though the MINI 360 M12SS takes M12 x 30 mm. All six of these are on the Global Truss page.

How much weight can a lighting clamp hold?

Only what its own manufacturer publishes for that exact part number, and in this collection those figures run from 28 lb to 1,650 lb on the very same 2 in tube. Fit is the easy half of the decision and the rating is the half people get wrong, because a 28 lb plastic O-clamp and a 1,650 lb aluminum half coupler go on an identical chord. Two narrow half couplers from one corporate family make the point: CHAUVET DJ publishes 220 lb for the CLP-15N and CHAUVET Professional publishes 1,650 lb for the CTC-50HCN, both for 2 in (50 mm) truss. Every figure below is the manufacturer's own published number for that model, converted to pounds where the manufacturer publishes kilograms only.

Read each figure in its own manufacturer's words. Global Truss states a maximum load capacity on plain clamps and a maximum static load capacity on eye clamps, Event Lighting states a working load limit, ProX states a capacity, and CHAUVET states a load capacity and once qualifies it as vertical direction. Those are not one measurement, so do not compare them across brands, do not add two clamps' ratings together to reach a total, and do not read any of them as a design factor of safety. The number covers the clamp alone, not the yoke bolt and not the truss, so read the truss manufacturer's own load and span table as well, which we explain on the Lighting Truss page. Have anything overhead checked by a qualified rigger.

Why is a half coupler filed under Clamps and not Couplers?

Because on this store Clamps is fixture-to-tube hardware and Couplers is truss-to-truss joining hardware, and a half coupler grips a single tube in order to hang something from it. The name is the confusing part: a half coupler is half of a full coupler, so it grips one tube where a full or dual coupler grips two. If you are joining one truss segment to the next, you want conical couplers, tapered shear pins, spigots and spacers, and those sit in Couplers alongside the rest of Truss Accessories, Truss Corners and Base Plates. If you are hanging a moving head, a par or a speaker off a tube, you want this page.

Do I still need a safety cable if the clamp is rated for the fixture?

Yes. CHAUVET DJ tells you to fit a safety cable to every hung fixture, and the cable carries its own rating, 68 lb (30 kg) on the CHAUVET DJ CH-05 and 165 lb (75 kg) on the CHAUVET Professional SC-08. A clamp rating describes the clamp, not the wing nut somebody forgot to tighten, not the yoke bolt and not the fixture's own hardware, so match the cable to the fixture the same way you matched the clamp. Shop Safety Cables, and S-hooks for the power and data runs that follow the same truss.

How do clamps ship, and can I pick them up in Los Angeles?

Clamps are small parcel items, and anything we hold in Los Angeles can be picked up at our warehouse, though a good part of this collection ships from the manufacturer instead, so ask before you plan around a pickup. Parcel orders placed before noon PST on an item stocked in Los Angeles ship the same day. Will-call pickup is at 934 E 11th St, Los Angeles, CA 90021. If you are buying one clamp per fixture for a whole rig, call 1-800-700-4542 and we will check the jaw against your tube and the rating against your fixtures before you order.