Instructables
Picture of K'NEX Large Tower Crane
My first attempt at building a tower crane from K'NEX.

Specifications:
Height from floor to mast: 200cm/79 inches; if not for ceiling height limitations, it would have been 215cm/83 inches tall
Jib span: 160cm/63 inches
Total span: 240cm/94.5 inches
Base diameter: 46cm/18 inches
Maximum load: approx. 1 lb (yes, it sucks; K'NEX was not designed to handle large loads without an excessive amount of pieces to support its own structure)
Counterweight: 111 red rods, 62 yellow connectors, 36 red connectors
Time used to build: Less than 3 hours

Words of caution:
-Make sure you are in a very large and/or empty room when building this.
-You may exhaust your red rod collection; be sure to have a lot of them.
-This is an ad-hoc model; it may or may not undergo further modification (such as adding string, trolley, motor, etc.).

References:
- knex crane http://www.instructables.com/id/knex-crane/
- The LEGO inspiration: http://www.philohome.com/towercrane/tc.htm
- HowStuffWorks: http://science.howstuffworks.com/tower-crane.htm

Step 1: Base

Very simple lattice of grey and red rods with purple connectors. Red rods have been substituted by their metallic-coloured counterparts.

The crane base is fortified with purple and yellow connectors with green rods.

Step 2: Center and counterweight

Picture of Center and counterweight
The counterweight will require many many red rods and connectors.

Step 3: Crane jib

Caution: this part, containing purple connectors for its connections, is very weak and susceptible to collapse if left standing on its own without the counterweight.

The length of the jib is 7 grey rod + 7 sets of purple connectors ( +1 yellow rod for the bottom of the jib)

Step 4: Connect them all

Now be careful and connect the jib to the crane + counterweight, and then connect that assembly to the top of the tower via that bottom white connector below the large gear.

All that this crane is missing are cables for lifting and a trolley. I may or may not implement these at a later time.
 
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its huge its probaly taller than me
arrow shot5 years ago
6 and a half feet :O it probably falls over a lot doesnt it :\
xobile001 (author)  arrow shot5 years ago
If I purposely tip it over, maybe. But it's been standing on its own for a good week now.
what does ad-hoc mean?
xobile001 (author)  jmiester2 years ago
From our good friend dictionary.com it means: concerned or dealing with a specific subject, purpose, or end.

Basically I built it with the purpose of trying to build it.

I now realize many of my college professors have used that term incorrectly.

Maybe you can come up with a way for it to self-construct like a real crane. I'll try to come up with ideas as well.
ok cool :-) real cranes use a temporary brace that they slide up on and each new segment is simply slid in, the the crane raised again, another section slid in and so on till its as high as you want it...
Niiice. I'll start building/improving it tommorrow. Do you think you could make it "build itself" (sort of) like a real tower care, i.e. lift itself up on a frame then have another section slid in (repeatedly)?

P.S., how tall can it get?
kolkmanusa3 years ago
so how would you hook up a pulley so that it could pick up, say, a pencil?
would you please send me insteructions on how to make this tower crane because it looks coll!
dylan03454 years ago
i built it had to mod a little bit but im hooking up a motor on a spool and making it have a retractable string/hook
Shadowman395 years ago
Pretty cool; how much weight can it lift?
how many greys does it need
Probably not much.
xobile001 (author)  Killer~SafeCracker5 years ago
Exactly. K'NEX is really not the best material to lift stuff unless you have a really solid base. Some sort of gantry crane might be better at lifting.