Add Metal Threads to Your 3D Prints - Make Them Functional!

Connecting mechanical components can be a challenge with 3D printing. Tapping functional holes in plastic that can support a load is nearly impossible. I want to share an easy method I've found to add metal threads to a 3D print that you can do with just a soldering iron.

This Instructable is entered into the Full Spectrum Laser and Hack Your Day contests so if you think it's a winner for either one, I'd appreciate your vote! Thanks!

Step 1: Materials and Tools

You will need heat-set metal inserts for this. I purchased mine from McMaster-Carr.
http://www.mcmaster.com/#standard-threaded-inserts/=11e5sw6

The only tool you need is a soldering iron.

Step 2: Design Your Model

Your will have to have the right size holes on your model to fit the inserts. On McMaster, they list two tapered hole diameters. Find the sizes for your insert. The largest of the two is the diameter you will need to make your holes in your model. I usually oversize the holes in my models a little to accommodate for the 3D printer's tolerances. Mine usually prints holes smaller than they should be but yours may be different.

Step 3: Assembly

The next step is to 3D print your model. Once you've got your part made, then you can start assembly.

1. Heat soldering iron. Wait at least a minute for it to get hot. Remember to always be safe around heat!
2. While it is heating, you can position the inserts so that they rest on the holes.
3. Once the soldering iron is hot, place it inside the insert and push down gently.
4. As you are pushing, the insert will slowly sink into the plastic. You may have to wiggle the soldering iron back and forth to straighten the insert.
5. Continue applying pressure until the insert is flush with the plastic. Remove the iron from the insert.
6. Flip the part over and remove any extra plastic with a small knife or screwdriver.
7. Repeat for all other inserts.
8. Wait a few minutes at least before using the inserts to make sure the plastic is fully solidified.

The inserts will still be hot for a few minutes after so be careful not to touch them right away.