CNC Teardrop Trailer - Making the Side Walls




I decided to build a Teardrop Trailer and determined I wanted one that had a kingsize bed (I am 6'6) as well as a bunk for the kids to sleep in. So after doing some (a lot) research on the net I decided to go ahead with the project and purchased a utility trailer as a base which was 10 x 6.5'. After I had the trailer it was design time and I decided to buy some plans from the internet ( ) and modify them to fit the trailer I bought. I decided to use sketchup for this as it was free and they have great tutorials.

I quickly realized that due to the size of the teardrop I was building I would need to piece 3 pieces of plywood together to make the side walls, many teardrops only need one sheet of plywood for each side. After doing some research on the internet, I found some puzzle joints that have been used in boat building to connect pieces of plywood together and decided to give that a try. Luckily we have a Makerspace in Whitehorse ( ) that has a CNC machine which seemed the only practical way to get the joints to line up properly.

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Step 1: Design

After doing some Sketchup tutorials, I designed the overall Teardrop trailer in Sketchup including the sidewalls. Once I was happy with the profile, I split the sidewall into three pieces that were less than 4'x8', using a puzzle joint I made using some circles. The sidewalls are made from 1/2 inch plywood and are cut out from 4x8 sheets of cheap plywood as they are skinned on both sides so do not need to look pretty. The sketchup file is attached.

Step 2: Getting Things Ready for the CNC Machine

First step was to create a file with just the pieces that I wanted and export the image as a 2D graphic. This option is under the file menu in sketchup. Then you take that image and import it this software called aspire which turns it into a vector image and then into a tool path file which is what the CNC machine reads. The tool path file is basically a text file with X, Y, and Z coordinates that tell the CNC machine what route to send the bit along to make the cuts.

Step 3: Cutting the Wall Pieces on the CNC Machine

Once the file is ready, just secure the piece of 4x8 plywood to the CNC table, load the tool path file and hit play. It took about 10 minutes to cut out each side and I was able to do it over two evenings.

Step 4: Putting the Walls Together

I initially just pieced them together in the shop on the floor and was quite impressed at how well the walls fit and how strong they were. The CNC machine was definitely the way to do something like this.

The next piece was to put them onto the trailer and that also went fairly smoothly (though watch out for the wind until it is secured in place.) And finally I just framed up the walls to give them some strength in the other direction using 1x3 lumber.

Still have a lot more work to do to finish the Teardrop trailer but wanted to share my experience on making the walls.

Step 5: Some More Photos

Had a request for some more photos...

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    12 Discussions


    4 years ago

    I am looking forward to more updates :-)


    4 years ago on Step 4

    Really enjoying this build! Cutting the sides like a big puzzle... that's an awesome idea!


    4 years ago on Introduction

    Hey Steve, looks awesome, also from Whitehorse and looking at building one also. Curious where you sourced the trailer, is it just a 'regular' utility trailer? And where you got the aluminum from, is it two sheets across the top?

    2 replies

    Reply 4 years ago

    Just a regular utility trailer that i stripped down, came with electric brakes which i needed. The metal is from Duncans they are awesome to deal with. Yes it is two sheets across on top just finished riveting them together today.


    4 years ago on Step 4

    Wow looks great so far. I'm very interested to see more!


    4 years ago

    Cool idea with the puzzle joints. Interested to see your progress


    Reply 4 years ago

    I am taking lots of pictures and will make some more as it comes together.


    4 years ago

    Best of luck on this project. Can't wait to see the finished product.