Device Details


This is a simple mounting adapter that lets you securely attach a threaded device such as a magic arm to a table or desk using a readily available, inexpensive C clamp.


Thread the mounting device into the adapter. Clamp the mounting adapter to the desk or table using the C-clamp.

Build Instructions

Bill of Materials

To assemble the mounting adapter, you will need:

1 – 3D Printed C-Clamp Adapter (~ 12 g of ABS filament, $0.60)

1 – 1/4″-20 UNC tee nut, 5/16″ long ( e.g. McMaster-Carr ($0.30), Home Depot Canada ($0.48) )


You will also need the following temporarily to install the tee nut:

1 – 1/4″ Washer

1 – 1/4-20 UNC machine screw or bolt, 3/4″ – 1-1/2″ length


The adapter can be used with a variety of different C-clamps depending on the thickness of the surface. For example:

1 – 2-1/2″ C-Clamp ( e.g. Home Depot Canada (~$6))

  • Screwdriver / wrench to install tee nut
3D Printing

The mounting adapter should be printed with the following parameters:

  • ABS or equivalent filament
  • Support on
  • 0.2 mm layer height
  • 60% infill
  • At least 2 perimeter layers
Assembling the C-Clamp Threaded Adapter

Clean out the support material from the bottom of the mounting adapter. There is a thin sacrificial bridge covering the holes for the tee nut that can be pressed through using the bolt.

To install the tee nut, line up the barbs of the tee nut with the slots on the mount adapter. Put the washer on the 1/4″-20 UNC bolt, and thread it through the adapter and into the tee nut. Tighten the bolt until the tee is flush with the bottom of the adapter. You can then unscrew and remove the bolt and washer.

This video demonstrates how to install a tee-nut.