Power Drill Torque Couplings

Power Drill Torque Couplings


Mach III’s torque limiting coupling has been used for decades to turn heavy-duty power drills such as the Milwaukee Super Hole Shooter Drill and Unitec ETE 32 into efficient tools for opening and closing gate valves, butterfly valves, ball valves, plug valves, mud valves, sluice gates, slide gates and other rotary actuated mechanisms.


  • The torque coupling is set to slip at the pound-inch or pound foot value you specify. This is the “slip torque setting” and can be set at the factory prior to shipment or can be set or adjusted in the field with a spanner wrench.
  • The torque coupling has a #3 Morse taper shaft that connects directly to the socket of the drill.
  • When the drill is powered on, the torque is transmitted until the slip torque setting is exceeded. It then slips until the drill is powered off, preventing excess torque from damaging the equipment or jarring the operator.
  • No reset is required after the coupling slips.


  • Maximum slip torque setting: 2,796 lb.in (233 lb.ft.)
  • Consult Mach III Engineering if the intended use exceeds 1750 RPM.


  • Output couplings are available for a variety of geometries and sizes; see below.
  • If the socket size, bore size, or geometry you require is not listed, customized couplings can be manufactured. Contact Mach III Engineering to discuss your needs.


  1. T4X2R-STH is the base unit.
  2. Couplings attach to the face of the base unit and many are interchangeable without completely removing the bolts.
  3. Torque Setting can be done at the factory. All torque settings are +/- 10% of the specified value.
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Mach III
Product No. Maximum Recommended Torque Setting (Lb-In) InputLength (Inches) Outside Diameter (Inches) Detail Sheet Request 3D CAD Model
T4X2R-STH 2796 #3 Morse Taper 6.90 4.48 View PDFRequest

Steel Coupling Options

Product Code OutputRequest 3D CAD Model
COUPL-0300.750 Inch Bore with Standard KeywayRequest
COUPL-0640.750 Inch Square NutRequest
COUPL-0290.750 Inch Square SocketRequest
COUPL-0670.8750 Inch Hex SocketRequest
COUPL-045 1.000 Inch Square SocketRequest
COUPL-031 1.000 Inch Bore with Standard Keyway Request
COUPL-043 1.1875 Inch Bore with Standard Keyway Request
COUPL-040 1.250 Inch Bore with Standard Keyway Request
COUPL-053 1.375 Inch “D” Shaft Request
COUPL-032 2.000 Inch Square (Fits AWWA 2 Inch Operating Nut) Request
COUPL-057 2.250 Inch Square Request
COUPL-026 2.500 Inch Square Request
COUPL-06330mm Bore with Standard KeywayRequest

Aluminum Coupling Options

Product CodeOutputRequest 3D CAD Model
COUPL-0590.875 Inch Hex SocketRequest
COUPL-0781.375 Inch Square SocketRequest
COUPL-058 2.000 Inch Square (Fits AWWA 2 Inch Operating Nut) Request
COUPL-0622.000 Inch Square Socket with 8 Inch ExtensionRequest
COUPL-0612.0625 Inch Hex SocketRequest
COUPL-056 2.250 Inch Square Request