My daughter's tricycle had a broken pedal, so I decided to replace it. A 3D printed part and a simple stopper did the trick wonderfully.
First step was to draw a replica of the existing pedal in CAD software. I took some measurements and drew up a replica, taking in mind a few limitations of the 3D printing. The existing pedal had some grooves for tread on both sides, but I could only put a couple of grooves on the bottom of the pedal and had the full groove pattern on the top.
My idea to hold the pedal in place was to put a simple stopper in the middle of it. This could alternately be replaced with a stopper on either side as well. The stopper is just a simple piece of aluminum with a hole in the middle and a set screw on the side. The outer diameter of the ring should be thinner than the thickness of the pedal to ensure it does not get in the way for pedaling.
The next step is to find a friend with a 3D printer, or hopefully in the future win an UP! printer:) The printed part turned out great. The slot in the center is for the stopper ring. There is a hole through the pedal for the pedal rod to fit through.
Now simply slide the pedal and stopper ring onto the bike and tighten the set screw. The pedal should be able to spin freely.
Now we just have to wait for the snow to melt and my daughter will be off to the races!
Since most of this bike is made from plastic, maybe the next project will be a bike that is made from fully printed parts:)