Modular Chassis for Physics Activities

This chassis allows you conduct a wide range of experiments in the classroom.  I use it for the following experiments

• Bumper attachment: Students build bumpers to limit the peak force
• Driver compartment: Students investigate the Law of Inertia and the importance of seatbelts.
• Sail attachment: Students investigate Newton's 3rd Law and optimize their design for a sail car.
• Mousetrap cars: Using the template, we drill holes for a mousetrap and mount it to the car.  We then use the coupler to attach a 3/16 dowel rod to the mousetrap arm.
• Weight sleds: Students can add weight to the car and investigate acceleration according to Newton's 2nd Law.

The chassis comes in a long and short version.
I've printed 50 of these and have never had one break yet.
I print in either .2 or .3mm layers in PLA.
I print the seat compartment and sleds without supports.
I print the mousetrap coupler in sets of 6 usually with a raft to keep it from breaking off the build plate.

I use a 3/16" drill bit to ream out the axle holes and coat them with graphite to minimize friction. I also ream out holes on the chassis and attachments as needed, securing components with 6-32 screws, washers, and lock nuts for a sturdy and adjustable assembly.