By Erik Viker

Things fall down unless we take steps to prevent themfrom doing so. In the theatre, we suspend scenery,

lighting instruments and curtains overhead, dependingon top-quality hardware and equipment to guaranteesafety and efficiency. This article may familiarize thereader with rigging components commonly used in thetheatre, but cannot substitute for reliable training andpersonal responsibility. Theatre practitioners should bethoroughly trained by reputable experts in the field beforeusing rigging materials, as it is important to understandthe basic structural design properties of any material usedfor rigging scenery or lighting equipment. Rope, cable,chain and fasteners all have a certain breaking strength,the average force at which the material fails. A safety fac-tor (usually one-fifth to one-tenth of breaking strength)must be applied to any rigging equipment or hardwareused; for example, if the breaking strength of a certainrope is one thousand pounds, its working load limit mightbe two hundred pounds. Trustworthy rigging hardwaremanufacturers clearly mark working load limits on theirproducts or provide the information at purchasing.

Common Rigging HardwareAn anchor shackle is a U-shaped steel bow with a

removable pin (often threaded for secure attachment)engineered to provide substantial strength for overheadrigging applications. For example, the lA-inch screw pinanchor shackle manufactured by the Crosby Group has aworking load limit of half a ton. Shackle drawbacks includetheir potentially inconvenient two-part construction andthe need to carefully align all loads. To make certain theshackle's full strength is available, the load direction mustrun through the pin and the curve of the bow section,rather than sideways, which places strain on the "arms" ofthe shackle.

A locking link (or Quick-Link) resembles a chain link witha gap on one side closed by a threaded sleeve. Althoughlocking links are frequently used for light loads dueto their convenient one-piece design and self-orientingshape, many theatre technicians believe locking links arenot as trustworthy as shackles.

In some cases, turnbuckles can be used to easily level ascenery piece. Turnbuckles are usually steel frames aroundtwo threaded eyebolts, which can be lengthened or short-ened by turning the frame. The turnbuckle is attached to

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Some swaging hardware

one end of the lifting line of the scenery rigging, becom-ing part of the total line length needed to fly the scenerypiece.

Carabiners, steel loops with spring-loaded latches oftensecured with an additional threaded sleeve, originated asrock-climbing gear and have become popular for quickrigging applications. Only use versions rated for overheadlifting, as carabiner-shaped key chains are common, butcannot support even minimal loads.

Steel nuts and bolts often are used to secure chain

around a pipe or other fastener, especially in permanentor semipermanent installations. Nuts and bolts used forrigging should be of the same hardened steel variety,Grade Five or higher, identified by radiating diagonal lineson the bolt head and curved lines on the nut.

Rope, Cable and ChainTrim chain refers to short lengths of chain often used

to connect scenery to batten pipes for flying purposes.Only fused link chain should be used for overhead rig-ging. Grade 3 proof coil chain is commonly employed astrim chain, as the 3li6-inch size has a working load limit ofabout 800 pounds. Chain allows lengths of each line to beadjusted individually in single chain link increments. Chainmay be fastened with shackles, locking links or hardenedsteel bolts. Avoid using spring-latch "dog clips" or otherhardware not rated for load-bearing purposes.

Wirerope is frequently used to suspend scenery from flysystem battens. The variety known as 7 x 79 aircraft cable(manufactured with seven strands of nineteen wires each)

is common in the theatre and is available with black pow-der coating to make it less visible from a distance. Aircraftcable of the 7 x 19 variety that is Va-inch in diameter has a

working load limit of about 240-300pounds, depending on manufacturerand type.

Rope has been used in theatre rig-ging for countless decades and comesin many varieties, sizes and strengths.It is important to know the workingload limit of any rope used in thetheatre. Although manila rope is inex-pensive and strong enough for manyrigging applications, it tends to leavetiny splinters in unprotected handsand wears out more quickly over timethan do other ropes. Synthetic ropessuch as StageSet X (a very strongbraided rope with a polyester core)and Multiline II (a twisted three-

strand rope) are increasingly popularfor lifting, static rigging and generaltheatre work. At 3,4-inch diameter,

manila rope has a WLL of about 650pounds, compared to 2,300 poundsand 1,175 pounds for StageSet Xand Multiline II, respectively.

Several basic knots and hitches

can meet most rope rigging needsin the theatre, with the clove hitch

and the bowline being two of themost versatile. Remember, a knot

reduces rope strength by approxi-mately 50%, and a hitch reducesrope strength by about 25%. TheBackstage Handbook by Paul Carter(Broadway Press) offers helpful knottying diagrams for many commontheatre knots.

Cables, ropes or chains can beattached to scenery with D-rings,"hanging irons" or eye bolts.Hardware attached to sceneryshould be fastened by boltingentirely through the scenery framingstructure (not with drywall or woodscrews). If eyebolts are used, theyshould be the forged-closed variety.Even simple masking curtains orfabric drapes need careful planningbefore flying them overhead. Neverunderestimate how heavy fabric canbe, especially the thick velour usedfor masking curtains. Ensure thatsoft goods are attached to support-ing structures such as scenery bat-tens with an adequate number ofties. Most professionally sewn the-atre curtains include grommets andties every twelve inches along theupper hem, which is reinforced withjute or vinyl webbing. Most often #4black cotton tie line (or trick line) is

used for this and many other light-

load applications, but care shouldbe taken when using tie line in thetheatre because it has essentiallythe same strength as a shoelace andmay not be rated for load-bearingpurposes by manufacturers.

Swaging sleeves are copper orstainless steel oval tubes crimpedonto the dou bled-over end of

aircraft cable to form closed loops,usually enclosing steel supportchannels called thimbles. A thimble

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keeps the swaged cable from kinkingtoo sharply, which would reducethe cable strength. After swaging, a"go-gauge" measuring the resultingsleeve thickness is applied to eachsleeve to make sure it has beenadequately crimped. If correctlyapplied with a swaging tool, thecopper sleeve results in a connectiononly slightly less strong than theoriginal cable and creates an endloop suitable for shackles or otherhardware attachment. An alternative

method for making end loops in wirerope is the wire rope clip or cable clip,a U-shaped bolt with two hex nutsholding a saddle engineered to gripthe cable. Ideally, wire rope clips areinstalled with a torque wrench toensure adequate torque on each nutand should be applied carefully toclamp the saddle to the load-bearingor "live" side of the termination

loop.Polyester slings often are used to

suspend lighting trusses or otherheavy equipment overhead in con-junction with wire rope or chain.Slings have working load limitsupward of 2,000 pounds, dependingon the configuration in which theyare used. Reliable products includethe SpanSet Stagesling and theTuflex Roundsling. Of course, nov-ice riggers should consult expertsbefore attempting to work with suchheavy loads.

Rigging SystemsSome ofthe hardware and equipment

described here can be used to install stat-ic or dead-hung scenery in your theatrewhere no scenery movement is neces-sary or when simple masking is required.Many theatres are equipped with coun-terweight rigging systems comprisedof flown battens of Schedule 40 steel

pipe held up by wire rope lift lines run-ning over an arrangement of overheadsheaves (pulleys). Each batten is coun-terweighted by an arbor,a verticalrackholding removable steel weights, whichis raised or lowered by a rope control lineto move the batten and any attachedscenery. Some ofthe hardware describedin this article may be used to fasten scen-ery to counterweight battens, but onlytechnicians who have been thoroughlyinstructed in their use should operatecounterweight-rigging systems. TheStage Rigging Handbook by Jay O. Glerum(Southern Illinois University Press) pro-vides extensive information about the

complexities of counterweight-riggingsystems, and several theatrical equip-ment companies such as Sapsis RiggingInc. offer seminars on rigging systemoperations. Any time rigging requireswork where no railings exist to preventa fall,use a fallarrestdevicesuch as theCMCProTech rigger's harness or the OBIcrossover full body harness.

Even experienced riggers shouldnever work alone, and it is best to haveanother technician check your workbefore putting any rigging into service.If a rigging challenge is new to you,do not hesitate to call on an expert toassist with the engineering and instal-lation. The cost of a consultation willbe well worth the increased safety andliability protection. With careful plan-ning, informed hardware selection andadequate training, rigging in the theatrecan enhance theatrical design, whileensuring safety for technicians, perform-ers and the audience. ~

ErikVikerisan assistantprofessorof the-atre at Susquehanna University, wherehe serves as faculty technical director forthe department of theatre and teachescourses in theater operations, productionand stage management.