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Gold-tone copper shaft coupler with M3 thread and four screws

Unique-Bargains

Unique-Bargains Shaft Coupler 3.17mm x 4mm Gold Tone

SKU CH-GHC3-B3AY9

Connects a 3.17mm motor shaft to a 4mm propeller shaft using an M3-threaded copper coupler with four mounting screws included

  • Size/Dimensions20 x 9mm / 0.79 inch x 0.35 inch (L*D)
  • Connects 3.17 mm and 4 mm shafts for flexible RC motor mounting
  • Copper construction resists corrosion in marine and airborne environments
  • M3 thread and four screws give a secure, vibration-resistant joint
  • Compact 20 × 9 mm profile fits tight model compartments
  • Gold-tone finish adds a clean, professional look to the build

Gold-tone shaft coupler for RC motors

The Unique-Bargains coupler joins a 3.17 mm motor shaft to a 4 mm propeller or drive shaft on model aircraft and boats. Copper construction with an M3 thread provides a secure mechanical link for hobby drivelines. Supplied with four mounting screws, the 20 mm long by 9 mm diameter body weighs 9 g.

Hobby builders needing a 3.17-to-4 mm step-up

This fitting suits RC aeroplane and boat projects where the motor output and driven element differ by the stated diameters. It will not work for shafts outside the .12 inch to .16 inch range, for metric threads other than M3, or for high-torque applications that exceed the material strength of copper.

Steady torque transmission in small drivelines

Under continuous load the copper body transmits torque without the slippage sometimes seen in press-fit plastic adapters. The M3 grub screws maintain clamping force during prolonged runs, and the gold-tone finish resists surface corrosion from fuel residue or moisture. The compact .79 inch by .35 inch profile keeps rotational inertia low for responsive throttle changes.

Highlights

  • Connects 3.17 mm and 4 mm shafts for flexible RC motor mounting
  • Copper construction resists corrosion in marine and airborne environments
  • M3 thread and four screws give a secure, vibration-resistant joint
  • Compact 20 × 9 mm profile fits tight model compartments
  • Gold-tone finish adds a clean, professional look to the build

Specifications

Size/Dimensions20 x 9mm / 0.79 inch x 0.35 inch (L*D)
BrandUnique Bargains

Questions about this item

What motor shaft diameters does the 3.17mm to 4mm connection diameter fit?

This coupler joins a 3.17mm shaft on one side to a 4mm shaft on the other, matching the Connection Diameter given in the specifications.

Will the supplied M3 screws thread into my existing motor mount?

The package includes four M3 screws; they will engage any tapped M3 hole in the mount you are keeping.

How can I confirm the coupler is seated correctly after installation?

When fully tightened the overall length measures 20mm and the outer diameter 9mm, so the joint should show no axial gap between the two shafts.

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