For this project you will need :

Material :

Tools :

A cnc router or a laser cutter (think to the fablabs network if you don't have this at home)
A 3D printer with PLA
hex keys for M5 & M6

Step 1: Cut the Wood

Tips :

For the plywood I've used a downcut bit (2mm diameter).
I have a STEPCRAFT D600 with a M800 spindle : I've cut with a speed of 260 mm/min, spindle speed 3.
For the circle foot I've cut a 18mm oak plate to a 250mm circle. But I recommend cardboard because oak is expansive.

I give you here the DXF file with the profile.

Step 2: 3D Print

There is 6 items type to print :

Materiel : PLA, 0.4mm nozzle, 0.2mm layers

TIP : print the crank a little bit larger, scale 100.5 or 101%. This will help further to insert it on his axe.

Tap the spacers with M5. The thread must pass through the all length.

Screw the spacers on one profile.
Insert the pulleys.
Place the second profile and screw it.
Insert the crank : push it on the axe of the rollup pulley, it is normally tight enough to hold itself. If not reprint it changing the scale.
Insert the bottom bracket and tight the M6 screws in diagonal. You will notice the different sizes of the holes : some are 5.5 mm, the M6 screw will tap itself when inserting.
Tap the bottom bracket with M6.
Drill through the bottom plate to let pass the M6 screw, then drill to mid-point with a larger bit to let pass the head of the screw.
Screw the bottom bracket, not to tight to let the crane turn.
- you can add a washer between the plate and the bracket to have a smoother move.
Attach a string to the hook and to the main pulley.
- I've used a Flex filament for 3D printing. But anything kind of string can do the job.

My 3 yo son is happy :-)

As an extra, it is possible to decorate the crane with colored pencils, markers, paint ..

If you want to make this project and don't have a CNC router and/or 3D printer, contact me to provide you the parts you need. I am happy to help.