Shaft Coupler - 1/4" to 5mm

These stainless steel shaft couplers allow you to couple two size shafts together. They can be used for connecting motor shafts to drive shafts, or two different-sized shafts. These shaft couplers have a length of 0.75”, a outer diameter of 0.42”, and couple 1/4” to 5mm shafts.

Actobotics is a robotics building system based around extruded aluminum channels, gears, precision shafts, and ball bearings. Thanks to the two standardized hole patterns, nearly all Actobotics components can be intuitively connected together. The wide range of components makes building complex electromechanical prototypes or finished projects a reality.

  • Length - 0.75”
  • Diameter - 0.42”
  • Bore A ID - 1/4”
  • Bore B ID - 5mm

Shaft Coupler - 1/4" to 5mm Product Help and Resources

Core Skill: Robotics

This skill concerns mechanical and robotics knowledge. You may need to know how mechanical parts interact, how motors work, or how to use motor drivers and controllers.

1 Robotics

Skill Level: Noob - You will be required to put together a robotics kit. Necessary parts are included and steps will be easy to follow. You also might encounter basic robotics components like bearings, mounts, or other hardware and need a general idea of how it goes together.
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Core Skill: DIY

Whether it's for assembling a kit, hacking an enclosure, or creating your own parts; the DIY skill is all about knowing how to use tools and the techniques associated with them.


Skill Level: Noob - Basic assembly is required. You may need to provide your own basic tools like a screwdriver, hammer or scissors. Power tools or custom parts are not required. Instructions will be included and easy to follow. Sewing may be required, but only with included patterns.
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Customer Reviews

4.8 out of 5

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Good enough.

I'm using this to couple a stepper motor to 1/4-20 threaded rod. Its the best thing I've tried so far, but I wouldn't say I'm totally satisfied. The threaded rod is a bit under .25" in diameter, so there's wobble in the rod when you tighten the single set screw against it.

A coupler with 3 set screws per side might stand a better chance at aligning the two shafts, bit I've tried that and at these diameters its super fiddly.

I ended up wrapping teflon tape (the white stuff for plumbing) around the threaded rod before securing it in this. It was better but not perfect.

All that said, a solid 1/4" shaft would probably work great in this.

Just the ticket

I needed to couple the short shaft of a motor to a long threaded rod - the perfect solution.