Not sure if it was from playing too much Oregon Trail when I was younger but I decided to go about making a covered
wagon model to test out some concepts I've been thinking about; these included a modified axle design, a pivot axle in front and
a fold down back.
To make it a bit of a personal challenge I limited myself to a P1 sheet of 3mm hardboard and if I couldn't make it fit I had to
leave it out of the design.
Here's an early layout. Breaking the hoops allowed me to fit the design within my self imposed P1 limit.
Another view of my messy WIP illustrator file as I drag completed pieces onto the artboard, another later file has all the pieces with shared cutlines.
I decided to give my wagon a fold down back, shown above is the locked position (left), you lift it to rotate in the hole provided (middle) shown open(right)
Shown above is the back axle. I'm finding black candle wax on these bearing helps lower the friction further and allows the wheels to spin very cleanly. I let the laser kerf be the distance between the parts and that seems to work well. Basically you cut half circles and place them into notches in the axle giving
you a round shape where it contacts the mounts. Another key to smooth movement is making sure you have the wheels exactly 90 degrees to the axle.
A test roll will quickly expose any wobble from a misaligned wheel.
I forgot to make enough clearance for the front axle when it is turned 45 degrees; another 2mm in mount spacing would have cleared the bottom of the pivot point. To get my prototype rolling I trimmed off the corners with a extaco blade (shown above). I also miscalculated the room the pivot joint needed at a certain angle to clear the "pull bar" mount.
Things I need to update.
-Front mounts higher by 2mm, remove 2mm in height from pivot joint to keep wagon level.
-extend lower wheel mount forward to help "pull bar" clear rotating pivot joint cleanly.
-add another larger half circle to inner axles to keep the wheels from moving too far back and forth in the mounts.
-add small notches at base of hoops to allow easy addition of a fabric cover.
I figure once I have the wheel elements working the way I want them I can make other models like a stagecoach using the same basic framework.