This toy crane is a simple wooden design, meant to be created by small kids with hand tools (except drilling) under close adult supervision. That said my 4yr old is quite good with power tools so we used them. The concept is my sons, I only help create realistic boundaries, and designs that he can make. That said he wanted a 5 meter crane (“top of house”), after some focus groups we settled on 750mm.
You could simply follow these plans but I really recommend that the child draws there version first and that you as a parent carefully steer them into these plans. Words like "I don’t think we have that special tool (triangular brill bit in my case), but we can do it this way" have always helped me and will engage the child.
The size of the holes in the boom, are only different sizes for the desired look. As well as the dowel rods. These could easily be replaced or changed depending on what you have at hand.
The plans attached are the easiest to follow. They were created after the project just for this Instructable and cover better ways of doing parts of this project.
Step 1: Tips
As the parts are in pairs a tip is to always place the parts on top of each other and screw them together. Then saw and drill the parts according to the drawings. This way everything will alight just right when it comes time to assembly.
If the dowel holes are not quite right go back with a 10,5mm drill bit to make the holes a bit bigger and give yourself some wiggle room
Don’t drill the holes with nothing under them, you will suffer some really bad exit holes. Drill onto a sacrificial board that supports your piece.
Take it easy on the glue the more that squeezes out the more cleaning or sanding you will need to do.
Paint all the pieces after the test fit, its way easier! Then assemble. If needed you can always touch up after the final assembly
Step 2: What You Need
Here is the stuff you will need:
· 2 meters 56mmx15mm
· 2 meters 43mmx15mm
· 3 meters 10mm dowl rod
· 300mmx300mmx15mm board or sheet wood
· 120mm M3 threaded rod (Stainless would save a lot of time)
· 5x m3 nut
· 2x M5 large washer (ISO 7093)
· 1x lazy susan bearing 50x50mm
· 1x aprox 3mm diameter nail
· approx 1.5 meters of string
· Wood glue
· 2 part 5min epoxy
· Screws 4,5x 30mm wood screws
· Wood filler, depending on quality of drill bits.
· 120 grit sand paper 80/60 for rough wood
- Drill and drill/spade bits. All sizes not needed but looks nicer
- Maybe 10,5mm as well
- 15mm spade bits
- 50mm or 55mm hole saw
- Screw driver for screw type
- Soft face hammer.
Step 3: Marking Out the Wood
Start by transferring all the dimensions from the drawings onto one of the pairs of wood for the Tower, boom and tower housing.
Step 4: Cut and Drill
1. Cut and drill the holes according to the drawings
2. Cut the tower ends and the dowel rods. Note the dowel rods are in two sizes for the tower and boom
3. Cut the rest of the parts
Step 5: Test Fit Paint and Glue
1. Test fit the parts for the tower and boom to make sure the dowel rods align.
2. Take apart the test fitted parts and sand everything, add wood filler as needed, then sand again. Repeat this process until the finish is great.
3. Paint everything in the desired colors. Its import to make sure the ‘inside’ parts are painted before final assembly two coats should be good. I found it easiest to drill a lot of 10mm holes into a scrap piece of wood to hold the dowel rods. You don’t need to paint the last 10mm of each end.
4. Glue the ends of the dowel rods and place them into the boom and tower. Once the rods are in one side place glue on the other side of the dowel rod and push on the other side of the tower of boom. I added the tower house after gluing up the boom but it could be done at the same time. You could also glue the handle dowel onto the handle at this point.
Step 6: Tower to Base and Attaching the Bearing
Place the tower in the middle off the base plate and draw around the tower. Remove the tower and then make a new square 10mm smaller inside the original square. At this point its best to look at the drawing to see where to drill the pilot holes for the screws. 3mm bit should be good. Place the tower back on the base plate so that it sits back inside the original box and screw the middle screw. Rotate the tower to make sure the corners line up with the first box and screw in the rest of the screws.
Place the Lazy Susan bearing on a flat surface. Add as much epoxy as possible to the outer edges approx. 2mm high. Make sure that the epoxy does not get into the bearing and keep in mind that one side of the bearing rotates in the middle, so no epoxy there. Place the glued bearing onto the top of the tower. Wait for it to dry, it says 5 min but leave it for a few hours, overnight would be best.
Place the boom on top of the tower and setup a make shift stand so that the boom is level. Use a spirit level to make sure. Once happy epoxy the top of the bearing and place the boom on top resting it on the makeshift stand. As the boom is so light place a few heavy things on top of the boom. Try not to completely squeeze out all the epoxy.
Again, this is the way we made it, the PDF drawings are a reflections of lessons learned. And will be easier.
Step 7: Winch Assembly
The threaded rod is a pain to bend without it breaking. I did not use stainless and it kept breaking on me. When I did get a good 90 degree bend I epoxied the joint just to make sure it would hold. The easiest way to bend the rod is to hold the last 15mm in a vice and gentle bend that over. If you cant get it right just keep it straight, see next step.
Once the epoxy has cured, its time to assembly the winch. Method 1. Insert the threaded rod into the hole and keyway, then epoxy in place. Method 2. Add an M3 nut to the end of the rod and leave about 5 to 7mm to the end of the rod. Make sure the hole in the handle is big enough so that the M3 nut sits flush with the inside of the handle. Epoxy both the nut and rod into the handle.
Once this epoxy has cured a few hours insert the rod a little into the tower house until it just pokes out the first wall then add your first nut followed by washer and second nut. Screw these down the rod and add your second M3 nut, washer and last nut. The first nut you put on should be screwed all the way to the end until there is only about 5-8mm of space between the handle and the outside wall of the tower house. This should mean that the rod is now in place. The second nut and washer assembly should be about 35mm apart. Once all the nuts are in the correct place firmly tighten them in place. The handle should turn with a little resistance.
Step 8: Boom Glide
Insert and glue the headless nail into the very last 3mm hole. Fill the remaining holes with wood filler. Let dry the sand with 120 grit paper.
This is just a nice smooth surface for the string to run over.
Now's a good time to sand and paint any surfaces you are not completely happy with.
Step 9: Nearly Done
Add string to drum assembly. If the knot in the string just slips (stays there) when turning the handle then either use two more nuts to squeezing the string or epoxy it in place.
Step 10: Finally
Add a Lego bucket or magnet to the other end of the string and You’re done.
If you have a child prone to lifting very heavy things then screw the base plate to another larger plate and weigh down the edges.
Step 11: Safety
Obviously this can tip over if trying to lift heavy things, limit the size of the bucket to ensure that the crane wont tip accidental. If you are unsure, use a bigger base plate
Hope you enjoyed this and make your own.