AIEL MARKET
Purchase Guide

STAGE CLAMPS
for the
PERFORMANCE INDUSTRY

THE FOLLOWING MAY NOT BE REPRODUCED
WITHOUT PERMISSION FROM THE AUTHOR ©

CLAMP TYPES

  HOOK CLAMP

    One of the basic, and lightest, clamps used for the stage, it is typically seen in smaller lighting setups as used by DJs and small bands. It fits 25mm pipe, although a larger version now exists to fit standard 50mm theatrical piping.

    These are usually made from formed steel strapping that has been drilled and tapped on one part for a long bolt used to secure the clamp to a support, and drilled at the bottom for a bolt/washer/nut that secures a light or similar object to the clamp. The top is crooked so that under gravity, the clamp will hang in a such a way that it cannot slip off round piping. The long bolt will tighten at an angle to secure the clamp to a pipe or other support.

    Underneath, the light or object is secured to the clamp by the bolt/washer/nut combination. Since this must be loosened to pan the light, it is not considered a "safety" clamp (see next), and thus safety cables should always be used with this type of clamp hardware. It is recommened to add a split (lock) washer next to the bolt head so that when it is tightened, it will be less likely to back off under vibration circumstances such as road travel.

    When purchasing, always select ones with thicker steel that is painted or plated, and also with the other hardware plated so as to prevent corrosion. There are also aluminum versions, but these should not be used to hold heavy objects as they are not as strong as the steel ones. In addition, some Hook Clamps have long bolts with plastic knobs. These are not as robust and should not be over tightened because over time the knob may split from constant hard usage. Instead, try to get ones with bolts that have a thumb or wrench head made of steel.

  `G' CLAMP

    The big brother to the above, it is often referred to as a `G' clamp because of its shape. It can hold greater weights than the typical Hook Clamp. It usually has a cast iron body and more robust hardware. The cast part has corrugations so as to grip pipe or scenery frames, and some have a crook at the top as an additional preventative to slipping off piping when hung in its natural gravity-down position. The bolt that tightens to the pipe usually has a square head that takes an open-end 13mm wrench, although there are some versions with thumb turners.

    The big difference with this clamp compared to the Hook Clamp is that it has a captive stud that is used to hold the light or object, and it has a "pan" bolt to allow horizontal (panning) rotation of the light. Thus, one tightens the hardware as much a spossible to hold the fixture to the clamp, but never loosens it to pan. Instead the pan bolt is used to allow this movement and to then lock it as desired. So even if this pan bolt is left loose, the light can never fall because it is captive to the stud which is captive to the clamp -- hence the "safety" designation. Even with this, it is also recommended that a split washer be added.

    An aluminum version is available, but as discussed before, do not use it to suspend heavy objects; nor should one overtighten this type of clamp to a pipe because it may break.

    There is now an aluminum, non-safety version that is on the market that does not have a stud or pan bolt. This makes it considerably lighter, but be sure to use safety cables with this clamp because techs often leave loose the bolt that secures the fixture so as to facilitate fixture panning (focus) adjustments. A safety cable is recommended because when subjected to enough vibration, it is possible for the loose bolt to back off and the fixture to release itself from the clamp. Because of this, please add a split washer to the bolt.

    If purchasing when the weight of the clamp is not an issue, select the iron version and with plated hardware. This will hold heavier objects and not rust. Lighter objects can use the aluminum version, but please use safety cables when using any non-captive stud version.

  SPRING CLAMP

    For purposes that demand greater holding strength than the simple Binder Clip, this clamp is far superior. Made from steel, it employs a large steel spring as its holding force. The grips are vinyl coated for better control, as are the clamp tips so that objects are protected from direct contact with the steel.

    Widely used in the video and motion picture industries to secure heavy drapery, camera flags, cables, and so on, this clamp also has uses for the stage and touring act where anything needs to be temporarily secured when a Binder Clip won't hold.

    Spring Clamps come in a wide variety of sizes and strengths and can span openings of a few tens of millimetres to a 125 millimeters or more. There are also cheaper, plastic versions, but they are not as strong and seem to break too easily. In addition, these versions have articulating pads at the ends which flatten against an object for better grip, but it's been our experience that these often disengage from the clamp and get lost. If low cost and the articulating pads are desirable, and if they are not to be abused, they may suit your requirements. Otherwise, get the better, steel versions.

  BINDER CLIP

    Commonly seen in business offices and sometimes referred to as "Fold-Back" or "Fold-Down", these clips are often used for stage purposes from holding script pages and costumes together, through keeping light-weight curtains closed, to holding gel onto fixtures where a gel frame holder is not available or not suitable. They are popular because they are cheap, have broad clamp bars with finger grips that lie flat when the clip is in use, and they come in a wide variety of sizes and colours.

    Binder Clips are made entirely of steel, so they are fireproof. The springiness is enough to hold well to a variety of surfaces for light to medium duty tasks. The disadvantage is that they will transmit heat to one's fingers, hence a discussion of our final `clamp', next:

  CLOTHES PIN

    Yes! The Clothes Pin! They are typically used to hold large sheets of gel, diffusion media or other filters on to barndoors because they don't transmit heat to the fingers.

    Use only wooden ones, preferably the larger type with strong springs. These are an inexpensive item that can be very useful, so always have a dozen or so in your road inventory.

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