1 Groove

At iStudio Projects, our iSP Loft Block Series B 1-Groove Underhung is a precision-engineered theatrical rigging component designed for reliable single-line lift applications in counterweight fly systems. Built to clamp directly to the bottom flange of steel wide flange beams, this block delivers smooth, consistent rope travel with a 875 lb line load capacity in a compact, heavy-duty package.

AR is not supported on this device

Product Description

  • Model #: ISP.1G.8.25
  • Grooves: 1
  • Block Diameter: 8″
  • Line Load Capacity: 875 lbs
  • Dim A: 4 9/16″
  • Dim B: 3 1/2″
  • Mounting Hole Diameter: 9/16″
  • Mounting: Underhung — clamps to bottom of steel wide flange beam
  • Single-groove sheave rotating on sealed precision ball bearings for smooth, low-friction rope travel
  • Sheave fully enclosed in a rugged housing of heavy steel side plates welded to base angles
  • Underhung clamp design accommodates standard steel wide flange grid beams without supplemental hardware
  • Suitable for single lift-line applications or spot-rigging special loads on the grid
  • Warning labels affixed to each unit; line set number field included for field identification
  • Load Limit: Never exceed the 875 lb line load capacity under any circumstances
  • Rope Condition: Do not operate with twisted, kinked, or damaged rope; inspect rope at each use
  • Equipment Condition: Do not operate damaged, malfunctioning, or field-modified equipment
  • Clearance: Keep all personnel clear of rope paths and pinch points during operation
  • Annual Inspection: Required per ANSI E1.47; maintain inspection log for each unit
  • Mounting: Verify beam flange dimensions and clamp torque prior to loading; confirm secure seating before putting line under tension
  • Application: May be used singly or in groups; confirm compatibility with head block and line set configuration before installation

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