K'nex Tower Crane

About: I've been making stuff with K'nex since I was really young. If you have anything you'd like me to make, let me know and I'll try to make it and then make instructions!

Here is a tower crane I made one weekend that is about 75 inches (6.25 feet) tall. It has almost every function off a real tower crane. It can rotate 360 degrees, the trolley moves from the tip of the jib, all the way back to the tower, and the hook can lower all the way to the ground no matter where the trolley is. Even though the crane can only lift a few ounces, it was a build that I really enjoyed, and (if you have the pieces), I hope you will build and enjoy too! Please rate and comment! :D

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Step 1: Pieces Count

This tower crane is very large and uses MANY pieces, so it would be a really good idea to make sure that you have all the pieces before you start building. Note that the count may not be 100% perfect, but should be very accurate.

Gray (1 slot): 3
Gray (2 slot): 6
Orange: 142
Red: 17 
Green: 6
Yellow: 29
Silver Slide: 272
Blue Slide: 52
White Circle: 43

Green: 154
White: 131
Blue: 238
Yellow: 259
Red: 151
Gray: 13

Brown/Tan Clip: 13
Blue Clip: 36
Black Hinge: 4
Blue Spacer: 50
Silver Spacer: 105
Micro Chain Gear (Black): 4
Micro Gear: 2
Large Gear: 1
Medium Gear: 2
Small Gear: 1
Big Wheel: 5
Big Tire: 0
Small Wheel: 4
Small Tire: 4
Motor: 3
Chain Links: 162
String: 20-25 feet
Marbles (optional): 70-90 (depending on size of load)

Step 2: The Base

This is one of the easiest sections to build, although it could be considered the most important. 

Step 3: The Tower

Okay, I lied, this is the easiest section of the crane to build :)This part attaches to the base to hold up the jib and counter weight.

Step 4: The Rotating Mechanism

This little part is what makes the whole crane rotate!

Step 5: The Top of the Tower

This will hold the jib and the counter weight on it's sides.

Step 6: The Tower Tip

Step 7: The Jib

This will hold the hook and trolley.

Step 8: The Counter Weight

This small part will balance out the crane. 

Step 9: The Support Rods

These slim pieces will help distribute the weight of the jib and counter weight so they don't break off.

Step 10: The Winch

This will raise and lower the hook from the jib.

Step 11: The Trolley Mechanism

This will move the trolley along the jib.

Step 12: The Trolley

This will bring the hook along the jib.

Step 13: The Hook

This will lift the load.

Step 14: Inserting the Trolley Mechanism

This will connect the chain around through the jib.

Step 15: Stringing Up the String

This will connect to the winch and the hook.

Step 16: Assembling the Crane

This will show you how to assemble the crane.

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    16 Discussions


    Answer 7 months ago

    Hello! Wow it has been a long time since I made this, it took a while for me to understand what I meant by "micro gear"! I believe I was referring to the smaller gray/silver gears seen in step 7 "The Jib". I've attatched a picture for your reference.


    1 year ago

    How much weight can it lift?


    5 years ago

    Fantastic, neat, well thought-out instructions. I wish more people would do it this thoroughly. I will definitely build this wondrous piece. Absolutely brilliantly done.


    Reply 8 years ago on Introduction

    If you look at step 4, those are the kind of motors you will need. They work the best.


    Reply 5 years ago on Introduction

    I've noticed over the years that having more pieces definitely helps. The only problem I will have is that I may need a slightly smaller model, if you're able to make one, please?


    Reply 6 years ago on Introduction

    I got mine from an old micro roller coaster set, but I can't remember what it was called. You can search for "K'nex black sprocket" and you should be able to find some.


    7 years ago on Introduction

    hey, the rotating mechanism on mine seems to not support the weight of the tower, it bends and the axle rods snap out of place. Do you have any ideas?

    1 reply

    Reply 7 years ago on Introduction

    Can you email me a picture or video of where specifically it is snapping off? That would help me fix it and possible redesign the rotating mechanism completely. My email address is: "MrSmashCat@olivacentral.com" Thanks!


    7 years ago on Introduction

    Just finished building your crane shortend the front by two blocks and but them on the rear still had to add weight to rear but looks good. My grandson will love this. thanks.

    2 replies

    Reply 7 years ago on Introduction

    Yeah, it has been over a year sense I made this. Now I would definitely make the back end longer, as back then I didn't know much about these things. If you have anything other ideas on k'nex projects, let me know! I'm always open to ideas, the bigger the better! :D Anyway, thanks for the feedback, I'm glad you found this helpful!