Knex Tower Crane

Introduction: Knex Tower Crane

About: I love building. A mechanical engineering student, most of my instructables involve modeling projects, K'nex ball machines, and Lego creations. I am also a model railroader, and I enjoy science (astronomy is m…

My first large-scale knex project! This is a great Knex Tower Crane that is 6.2 feet tall and has a boom 4.11 feet long. Very durable, it has stood for two months in my room under all kinds of tests. (There is a limit to it's ability, though.) I hope you like it, the crane rotates and has a working hook. You can make your own hooks for various tasks.

Step 1: Piece Count

 With this large a project, piece counts are necessary!
Subject to small counting errors.


1-way grays: 58
oranges: 40 (68 if fully cross-braced)
reds: 20
greens: 4
snowflakes: 32
purple snaps: 222
blue snaps: 94


green: 80
white: 72
blue: 106
yellow: 73 (129 if fully cross-braced)
red: 147
gray: 68
black: 2


tires: a whole lot!
blue spacers: 20
gray spacers: 9
small blue gears: 2
medium yellow gears: 3
big yellow gears: 2
tan clips: 14
blue clips: 7
string: a reasonable amount, yarn works well

Step 2: Base and Tower

 Not hard, just follow the pics!

Step 3: The Gearbox

 This little rig makes the entire boom rotate with the turn of a crank!
I assume that it could be fitted with a motor if desired. I simply don't have one.

Step 4: Boom Base and Winch

 This connects the boom to the tower. Follow the pictures or the model won't work.

Step 5: Winch Casing

 This is for strength, but it also makes it realistic.

Step 6: Counterweight Bin and Connecting Beam

 This handy device will hold the counterweights to balance a load!

Step 7: The Hook

 This is my model for a hook, anything will work.

Step 8: The Boom

 This is what makes a tower crane a tower crane!

Step 9: Final Assembly, Part 1

 Connect it all, and have fun with your new awesome model!

Step 10: Final Assembly, Part 2

 Ok, now you're done!

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    Reply 8 years ago on Introduction

    Sorry, I built that over three years ago...but the basic idea was to make a frame that rides on those tracks. It's just a series of white rods and 2-way gray connectors...I found the technique in another Instructable, I believe.


    9 years ago on Step 4

    How exactly do you wind up the string onto the winch?


    Reply 9 years ago on Step 4

    Good question! The tan clip and the blue clip should be closer together than in the above pictures (I've added some new ones to illustrate better). Simply knot the string around the tan clip's peg and push the blue clip against the tan clip. This closes the string in, and when the rod is turned in either direction, the string is forced to wrap around (instead of loosely hanging on the rod itself and never winding in). Hope this helps!

    Knex Tower Crane Winch String Attachment.JPGKnex Tower Crane Winch String Attachment 2.JPGKnex Tower Crane Winch String Attachment 3.JPGKnex Tower Crane Winch String Attachment 4.JPGKnex Tower Crane Winch String Attachment 5.JPG

    11 years ago on Introduction

    I will have my instructions for mine on the site this weekend Sunday at the latest.
    Sorry for any inconvenience.


    Reply 11 years ago on Introduction

    Either you're taller than you think, or (more likely) my measurement was wrong. Sorry for any inconvenience.


    11 years ago on Introduction

    Very nice. I am making a tower crane of my own, and I will probably post it when I finish it (which will hopefully be in the next few days).


    11 years ago on Introduction

    i built a tower crane that looked just like this a wile back but i did'nt post it. it used chain to move the hook back and forth and thread instead of rods for the support cable other then that it was the same