Our ancient scrap wood fort was due for an upgrade. So, the kids and I designed and 3D printed a modular construction kit for endless fun.

From Scrap Wood to Super Fort

Many years ago, when my kids were little, I built them a basic fort from scrap lumber. It was rough, but they loved having their own space to fill with pillows and toys. That fort is still in the shed, but instead of dusting it off, I decided they needed a modernized upgrade.

I am home on vacation this summer, so it was the perfect time to tackle this project with a few requirements in mind:

• Infinitely scalable
• Easy for kids to build
• Colorful & Customizable
• Sturdy enough to hold a bunch of blankets
• Readily available parts

Fort construction has two main building blocks: connectors and struts. The kids and I took a trip to our local Lowe’s and picked up a pile of 3/8" x 4' dowels, which we cut into 16" segments.

Side note: During testing, we ran out of 3/8" dowels from Lowe’s, so I decided to grab some from Home Depot since they’re much closer. Turns out their 3/8" is different than Lowe’s 3/8" and the lot needed to be returned. They were slightly too small in diameter. Precision might be asking too much from the orange big box construction store, so we’re going to be sticking with blue from now on. After all, Lowe’s has a veteran discount.

With the rods figured out, I just needed to make all the connectors. I measured the dowels, designed a simple connector in Fusion, and printed a metric ton of them. After a few prototypes, the final version was snug enough to hold firm but easy enough to pull apart. Since the dowels weren’t all perfectly uniform, I also printed a rubber mallet out of TPU and PLA, which made the kids feel like real construction workers. Some of the rods were tight, but fit perfectly after the first try.

The kids were involved in the whole process. Once the parts were ready, they went to town, building living rooms, kitchens, and even an escape tunnel. They ran out of rods in a few days, so it looks like another trip to the hardware store is in my future.

Their next plan is to build a giant fort for our Family Movie night, complete with sleeping bags and snacks. If you want to print your own connectors, grab the .3mf here. It’s a great way to use all those nearly empty filament rolls that take up space.

I’m going to share the connector design on MakerWorld and Thingiverse in case other dads want to build forts with their kids as well. I aimed to make this design easily accessible with off-the-shelf parts that didn’t cost a fortune.