This is not a complete instruction and should be used more as info to inspire your own build. Ill try to document and show how I did stuff, but before and during the build I expect you to re-measure and adopt. You will probably not be able to use these instructions without modification and some of your own engineering. I will not promise that this instructions will work out of the box, instead Ill promise the opposite, this will probably not work without changes/adaptations so be prepared for that. :)

I manage to get a wheel-base,break and handle from another wagon (dumpster find, I found a bad throwaway bike wagon, a North 13.5 Roadster wagon) and I had wheels (2x20", 1x16" from another wagon) that fit. The width to the build in my info will be based on the wheelbase I used e.g. 615mm and needs to be adopted if you try this with other parts.

Most part I found a my local hardware store, many of the small special screws and stuff could be bought per item or per weight so I almost never had to buy a box of things. 

The aim for this step is to create a frame to add the wheel base, handle and the slider.

To think about in this step:

• Slider length (750mm in my case)
• Width of wheelbase screws.
• Position of wheel and slider fasteners so middle beam and wheelbase screws are not in the way.
• Leave room in the back behind the slider to fasten a handle (I used 30mm)
• I will have a front area sticking out in front of the slider (yes this complicates things a lot) so I selected shorter frame compared to the slider in the front, so it can be fasten in a good way.

A frame was created using square 20x20 aluminum pipes to fasten the wheel base and sliders on. For the corners I found nice plastic "create a shelf system" corners, The idea here is to make a frame there to keep the wheel base and slider in to proper position. I created it with one middle beam to make it more sturdy, the wheelbase will also work as a middle beam.

As my wheelbase is fasten 595mm apart I select 615mm (595+2x20/2) as a width of the frame so the wheelbase will be fasten in the middle of my 20x20 pipes.

I used the following measurements:

• Outer frame size: 725x615mm
• Middle beam at 400mm from back
• Wheel rotation center 260mm from back
• Slider 30mm from back

Main parts used:

Slider 750 mm with locking	1 pair	For the extendable bed area
Aluminum beam 20x20x1 mm		For frame structure
X-Fastener (X-förbindelse) for Aluminum 20x20x1mm	2 x T-shape 2 x L-Shape 2 x 3way corners	To make the frame shape like a digital 8, The 3way corners was used in the back to create something that I could fasten the handle on, depending on your handle solution this could be replace with L shaped.
Angular fastener (Vinkelplåt) left/right 45x60x16mm	4 left 4 right	To fasten slider to frame
Wheelbase for 2kids bike wagon	1	This will determine the width of the build
Handle with fasteners from (same) 2 kids bike wagon		I got the pipes holding it to the original frame and the folding endcaps to the same handle.
Aluminum beam 25x25x1 mm	150mm	Just used to fasten the handle pipe folding endcaps to 3way X-Fastener  (X-förbindelse).

Angular fastener (Vinkelplåt) - I use both a big and a small version in the build, the big is for fastening the slider to the frame and the smaller is used later in the inside for the bed area. NOTE: The picture above with measurement is from the smaller one but the you look and work the same

My X-Fastener  (X-förbindelse) used 20mm in each "corner" so I cut my pipes a bit shorter.

Before sawing the pipe I spend some time to figure out in what holes on the slider to put the angular fastener (Vinkelplåt) and if I should use left or right version against the frame pipe to make it work compared to the wheelbase and middle "bar". I also decided the needed space behind the slider for the handle (30mm). I ended up using a mix och left and right version on each side to make the fastening points end up in "clever" places. In the front I place backwards to make sure I could have a shorter frame. Going from front to backwards I used made the first point backwards (as mentioned), then front, front and the last backwards, but this depends on the holes on your selected slider, the wheelbase and where you place the middle bar in the frame. I also wanted to make the fastening easier by trying to get them into the plastic of the X-Fastener (X-förbindelse) as much as possible where I could just use a wooden screw. There is picture a bit below.

In my case I ended up with this:

For the length I made two of the following setup (from front)  L-shape  X-Fastener  (X-förbindelse) , 300mm pipe, T-shape  X-Fastener , 365 mm pipe and last a 3 way  X-Fastener (20+300+20+365+20=725mm) . And for the sides I made 3 x 575mm pipes (20+575+20=615mm). 

I then used a rubber hammer to make the pipe and the X-Fastener (X-förbindelse) stick together.

NOTE: I first didn't use the X-Fastener  (X-förbindelse) 3 way corner at the back but a L shaped one, later I replaced it with a 3 way one but some pictures are taken from the initial assembly. (Sorry about that)

Then I fasten the slider using the big Angular fastener (Vinkelplåt), as mentioned before a lot of planning was done to get them near but not in the way from the X-Fastener  (X-förbindelse), middle beam, wheel base and also the front part of the wagon to be able to build a plaform in front of the slider.  To fasten it on the places where they where near a X-Fastener  (X-förbindelse)  I just used wooden screws (4.2mm and predrilled 3.5mm hole) Only one pair ended up not over a X-Fastener  (X-förbindelse)  and for it I used a M5 rivet nut tool that I got for the project, but you could also just drill all the way trough and use longer screws with a normal nut.

I also drilled and fasten the wheel base so the wheel rotation center ended up 260mm from back, I hope this will be good but unfortunately I have a hunch that it would be better to have it even further from the back to have a better balanced wagon, but we will see.

Here is a picture of the frame with the X-Fastener  (X-förbindelse), wheel base and Angular fastener (Vinkelplåt) on it. I hope this picture clears up some of the description above.

On the back behind the slider the handle will be fastened. I initially was going to just put some square pipes and figure out how to fasten the handle I had. But I discovered that I could also take the pipe the handle was fasten to from the broken wagon together with some nice plastic end caps that will make them foldable. Then endcaps was fasten to a 25x25 square pipe on the original wagon so I fasted so short (65mm) 25x25 pipes on the X-Fastener  (X-förbindelse) 3 way corner with some wooden screws (4.2mm and predrilled 3.5mm hole) roughly like this:

I added a 20x20mm pipe in between the X-Fastener  (X-förbindelse) and the 25x25mm pipe but that was unneeded and if I redo it Ill remove it, the wooden screws holds it firmly enough.

The 65mm long 25x25 pipes was measured to make the pipe fold down perfectly right above the slider.

I fasten the slider to the Angular fastener (Vinkelplåt) using M5 screws with flat heads. Now the frame is ready!

I don't trust that the X-Fastener (X-förbindelse) would not slide out during usage later so I will add an extra screw for each pipe where there is none already, but I will do it in the end to leave room to move stuff to make the slider operate smooth if something ends up a bit "not perfect", then I can make some small adjustment by moving the frame pipe on the X-Fastener (X-förbindelse) slightly. BUT do not forget to to it in the end.

The front platform is a about 500mm long in front of the slider. The idea is that the front can be opened and one can access the stuff inside, plan is also to make this a way to climb into the wagon and a place to sit and rest or eat on the road.

I also wanted to see if I could make the front non square so that is also a big reason for using 750mm sliders and adding this platform infront outside the sliders compared to just using 1000mm sliders and having a much easier design. I also want to be able to detach this fairly easy for transportation.

Main material

• Aluminium L shape 65x35x2 2x150mm
• Plywood 615x530x15 (I had this at home but less thick probably work)

The plywood needs be fastened to the inner area of the slider in the front screw holes. The plywood should stick out about 500mm in front of the slider (or the length you want for the living area. The problem is that the frame is in the way AND the inner part of the living area will end up inside the slider, e.g. from the inside 

1. Inner, "back" living area, fasten to the frame e.g. not moving.
2. Outer, "middle" living area and "front platform", fasten to the inner sliders e.g. moving
3. Slider, outside fasten to the frame, inner part moving, outside part not moving.

So the plywood needs to be below it the Inner "back" living area when not slided out.. (If this description didn't make sense it might be good to re-check this after reading further down) 

I didn't find any thing good to buy to solve this. But fortunately it will be quite easy to solve it by making our own fastening bracket. Using a aluminium L shape beam 65x35x2mm and sawing it 150mm long and saw a jack so the 65mm side can be fastened in the slider but the 35mm side can be below the inner area. Like this:

I made it so the plywood will end up at the same level as the frame. I'm not sure if that will be good or bad but remaking new brackets will be easy if needed.

I saw jack in the plywood to match the brackets and drilled two 6.5 mm holes into plywood and the brackets to fasten it.

I used 4 x M6 screw with a flat head and fasten of with a bigger hand tight-able nut so I can disassemble/reassemble it easy for transportation. I found quite fancy ones but a wing nut would probably work equally god.

I didn't put the screws too tight to the frame as I might add legs her, we will see.

As making the fastening angular thing turned out quite easy I could have made my frame go all the way up to the length of the slider. That would make things much more easy. If you do it in your build let me know how it worked out!

The aim for this step is to provide lower support for the living area to rest on. For the back living area this will be placed inside the sliders fasten to the frame. The middle living area will be fasten around it and fasten to the slider (so it will slide out). The reason the outside slides out and not the mode easy to build inside is for a few reasons

• I  want to add stuff to the walls in the inside. Maybe have a small area and a hatch on the back near the handle so I can access stuff both from inside and outside the wagon.
• Try to make most of the airflow from the front go around the wagon and not being pushed inside it. 

Main material used for this step

• PVC L-beam 20x30x2mm (for "back" inner area) fasten to fram
• Aluminum L-beam 10x10x1mm (for "middle" outer area) fasten to slider with:
• 6 x The small angular fastener (Vinkelplåt) (to fasten the aluminum L-beam 10x10x1mm )

TBD

16" front wheel

For this build I used an normal 16" extra jogging front wheel for bike wagons but It's basically just a normal 16" wheel but with a bit longer fastening screws so it can be fasted to a 25x25mm square pipe instead of a normal bike front wheel frame.

TBD Plan to fasten it with 25x25 square aluminum beams on the plywood but might need to be fasten to the frame also for extra stability, it also need to be somewhat easy to add and remove it and use the extra front wheel instead to save space, but we will see how it turns out.

Extra freewheel

I had an detachable freewheel from another wagon that was fasten to the arm used to connect the bike wagon to the bike. I cut he arm before and after the wheel fastening and drilled two holes and added a two M6 rivet nuts (but you can drill all the way trough and use loner screws). I used a short square metal pipe as distance to be abble to access the release button so the wheel can be removed and attached easy. I then fasten it in the bottom plywood with long M6 screws so the wheel ended up as far in the front as possible but not sticking out over the edge (so that it don't take space in small spaces) and centered in the middle of the wagon.

TBD

Plan to use 25x25 square aluminum beams, but we will see. Legs should be fordable, and higher the the wheels to take all the weight when sleeping, and also to get the living area a bit higher and easy to sit/enter/exit.

The idea is to have 2 section about 800mm long, one inner and one outer section that when you "open" the slider slides apart and becom an about 1500mm section. (there needs to be some overlap for rain/wind protection)

Two frames will be made marking the outer sides of the 800x900mm areas made of PVC L-30x30x2mm, L40x10x1mm and I 20x2mm beams that can be removed and folded together and fasten to the slider. The plastic sheets will be fasten on top of the frames.

The back one is made a bit smaller to fit inside the one in front like a drawer. The back one is fasten to the base inside of the sliders and the outer will be fasten inside of the slider making it work like a drawer.

The plastic parts are fasten with M4 screws with large to be able to remove a few screws to detache it and then fold it for transportation. 

Glue the two plastic beams

Back are done.

Back area is fasten to the inner corner of the 30x20 plastic beams inside the sliders. The plan is that the cover sheets will later be fasten to the skeleton and be "outside" the L beam so water and wind will be directed outwards the living are by the beam.

The front will open frontwards using a 20x20 square aluminum frame as door frame and the front part on hinges fasten between it and two U shape 25x25 aluminum beams (one on each side) The idea with the U shape is to make sure rain and wind do not enter the living area. On the two U shaped beams a skeleton construction to reassemble the front of a Citroen Hy bus is created using plastic (PVC) L shape 30x20x3mm beams and 3D printed corners (more about that in another build step)

First the front door frame is created using the same aluminum 20x20 pipes and x-fasteners as used for the frame before. this frame is fasten ... The hight was used to 900mm 

I use two M6 screws to fasten this on each side lite this:

Front holding structure is in place

The front will be fasten with hinges to a U shape aluminium beam slightly larger then the holding structure to (25x25mm) to make the door more water and wind prof. The aluminium beam will cover the structure. (some holes had to be cut out on the inside to make it fit)

On the two U shaped beams a skeleton construction to reassemble the front of a Citroen Hy bus is created using plastic (PVC) L shape 30x20x3mm beams and 3D printed corners (to create the proper angulars) Onshape 3D (open/free version) was used to create a front shape from old drawing from the Citroen Hy and a bit adoptions of the size and angular to fit he wagon was made. From the fron shape the 3d corners was created so the L shaped beams could be fasten (using M4 inserts) and then printed.

Later plastic sheets covering the living ares will be fasten on this shape together with some open handle, front light and blinkers.  Bike light with a traditional bike light shape that match the Citroen Hy lights quite well.

Lets start:

The front shape was created in a cad program (Onshape free version) and a stl version of that file is among files in this project) from it a lot of measures and angulars where taken and a set of corners was modeled in Onshape that will support holding up a frame structure and that the covering plastic sheets can be attached. 

Front shape:

The 3d printable "corners" are also among the files with names that start with "left" and "right" those where printed (by my son, great thanks).

The 3d printed corners has M4 inserts that I melted in with my soldering iron. Then they was fasten to PVC L shape 30x20x3mm beams using the inserts and  flathead M4 screws, all lengths was matched so the corner to corner values from the cad file was the same (added with a red pen in the picture).

Downwards the sale PVC L shape 30x20x3mm beams where use so the inside of the L will agenst the outside of the plywood front platform. The platform was cur to match the shape. The front structure was the fastened to the aluminum U 25x25 beam. In the top a hinge is fasten so the same scruws goes from hinge, Ubeam and the is fasten to the 3d printed plastic part in the inserts. The other side of the hinge is fasten to the "Front holding structure" making the whole front work as a door.

The lower PVC L-beam will cover the plywood outer shape and form a weather barrier with the 20mm side going down and cover it side.

It turned out to work perfectly.

TBD The plan to use 3.5mm Acro/cell/coros plastic sheets. They are both kind of cheap and don't weight to much (700g/m2) and seem to be easy to work with.

It will cover the created skeleton and the plan is to use plasic U beams to hook into and "close" back and middle are when drawing it out to make sure the is no glitch for wind and rain to enter between the boxes.

The front are wil also be covered with this.