This is a design of T-nuts for 4040 aluminum extrusion profiles using M3 nuts and screws.
It can be used to fix light-weight objects on 4040 profiles.

Advantages of this design:

• easy handling (4040-t-nut-m3)
  A tight thread channel with narrowings helps to easily control the nut with the screwdriver. So you always can be sure the nut has turned correctly inside the profile.
• fixation of M3 nut
  By using the snap-in mechanism (https://www.printables.com/model/364572-nut-clearing-templates), the nut will not fall out of the t-nut unexpectedly, no additional gluing is needed. 
• printing without support
  All T-nuts can be printed without any support.

There is 3 different models available:

• 4040-t-nut-m3
  Standard type to be inserted and removed at any time.
• 4040-t-nut-m3-long-screw
  Long version to be inserted before assembly. It can be fixed with a 2.2x9mm tap screw
• 4040-t-nut-m3-long-m3
  Long version to be inserted before assembly. It can be fixed with an M3x8mm screw
   

Printing

• Material: PETG
• Infill: 100%
• Support: no