You can see when it's mounted to the wagon not only is it heartlessly plain (in this version), it also permits only very limited underlock. Underlock refers to the ability of the front (steering) axletree to go under the undercarriage for tighter turning. This allows an acceptable turning radius at outdoor events and only occasionally needs to "back and fill" indoors. This lack of underlock is in keeping with our theme from the Djebjerg Wagon.
Later on we'll look at a different version using the same running gear concept with slightly different dimensions. This one is on a later period theme with full underlock. Here I've mocked up smaller front wheels from some shop scraps and thrown a piece of plywood on to represent the bed. You may also notice I've lowered the overall height of the bed above the ground.
Before we go on to the "Plain Jane" version (why is it always Jane who is plain anyway? Personally, I think if a name was going to epitomize plainness it would be something like Irmingard. Oh, well...) this view shows a more elaborate axletree with cutaways, a shaped and tapered tongue, and wooden cheek pieces. We'll cover these when we talk about how to dress up the wagon later.
Here is the axletree set in place with the pivot pin in and ready to roll. You can see that the fifth wheel is actually two wheels resting on each other. One attached to the center pole and bolster, the lower attached to the axletree. On wagons of this size I prefer to have a bolster mounting the upper fifth wheel plate, rather that having the fifth wheel ride under the bed. I feel this arrangement is stronger in that it applies more bearing area for the pivot pin. I haven't experimented with an arrangement without a bolster because I am convinced the pivot pin would rip right out of thin plywood.
Here is the axletree, tongue, and fifth wheel plate. The axletree has been ripped down to 5 and 3/4" wide and the dado for the axle cut and covered by the cut-off glued back on as described for the rear bolster. It is 28" long.
The fifth wheel is assembled from 2 eleven inch diameter disks of (in this case) 15/32" plywood. It really doesn't matter how thick the plywood for the 5th wheel is as long as it is 15/32" or thicker. In this case I had a scrap piece of 15/32, but usually I cut the 5th wheel from the same plywood as the wheels discs.
On the top of axletree is a dado cut to receive the fifth wheel plate flush with the top of the axletree. So it is centered 11" wide, and 15/32" deep. It is secured in place with two 1 and 1/2" drywall screws. Don't screw through the center point because we have to drill that out later for the pivot pin. Once the 5th wheel plate is attached turn it over and we can mount the tongue.
In the plain jane version the tongue is simply a 14" or so piece of 2x4. Mark a 3.5" circle at one end and trim it off to match.
A 3/8" hole drilled through at it's center point. Into the hole insert a 1.5" long, 1/4" i.d. piece of copper pipe as a bearing.
With the axle tree turned over use a square to center the tongue on the 5th wheel plate and clamp it in place. Screw the 5th wheel plate to the tongue, and mount the corner plates.