Using filament holes in 3D printed models

In this article, we’ll show you how to easily use filament to join two levels or parts of a model together in four steps. Top-locking mechanisms like filament guide holes are essential for all buildings with two or more levels. When the walls or floors of a model are not deep enough to use top-locking pins, filament guide holes are used instead.

These small holes help you align and pin two sections or create a top-locking pin to orient two floors. You will need the following to create these pins:

• An off-cut of 1.75mm filament, or a metal paperclip if you do not have an FDM printer
• Modeling snips or side-cutting pliers
• A hand drill or Dremel with a 2mm drill bit
• Super glue or equivalent adhesive

1. Use the hand drill to clear any debris that might have clogged the guide holes during the printing process. Make sure the drill bit is slightly larger than the diameter of your filament. Clean out both pieces of the model that are going to be joined together.

2. Insert your off-cut filament into the holes, and glue them in firmly. Its easier to put over sized pieces here and trim them after the glue has dried.

3. Trim them so that roughly 3-4mm is sticking out of the hole.

It’s best to leave them longer first, then trim further if needed.

4. Once all top-locking pins are glued in place and trimmed, test the alignment of the upper section. If it sits high, trim the filament pegs smaller or use the drill to deepen the receptacle hole. You can glue the whole piece together here if you wish, as the pins will make it a steadfast bond, more than if you just glued two smooth sections together.

When drilling the guide holes of a resin-printed model, remember to wear a face mask. We recommend using a straightened paperclip instead if you don’t have any FDM filament.