K'Nex Crossbow (mid 2010)

In the continuing series of posts of content from my old site, here is a a K'Nex crossbow I built in mid 2010. It's very clunky and weak compared to most K'Nex weapons other people have created, but I like how mime comes closer to mimicking a real crossbow. Some of the early versions even had a chain crank, but it got caught a lot.

Instructables

crossoverview.png knexcrossstrung.png knexcrosstrigger.png
Parts list
  • Rods
  • 15 Red
  • 50 Yellow
  • 82 Blue
  • 10 White
  • 95 Green
  • Connectors
  • 2 White
  • 73 Yellow
  • 5 Gold
  • 11 Green
  • 17 Red
  • 60 Orange
  • 43 Dark gray
  • 35 Beige
  • Misc
  • 7 Black rod/connectors
  • 23 Silver spacers
  • 36 Blue spacers
  • 2 Hinges
  • 2 Chain links
  • 13.5" Orange track
  • 40" string

Key
  • Build: build from scratch, unless otherwise noted.
  • Attach: adding pieces to an existing thing
  • Details: nothing new, just a different view
partslist.png
Step 1
  • 16 Yellow connectors
  • 12 Red rods

TIP: It is extremely hard to snap all of these together at once. Start by using the minimal amount of yellow connectors to make this structure then add yellow connectors one at a time.
spring1.png bothsprings.png
Step 2
  • 2 White connectors
  • 4 Yellow connectors
  • 8 Dark gray connectors
  • 2 Green rods

springrightstringanchor2.png springrightstringanchor3.png rightcentersetup1.png rightcentersetup2.png springleftstringanchor2.png springleftstringanchor1.png leftcentersetup1.jpg leftcentersetup2.png
Step 3
  • 1 Yellow rod
  • 1 Gold connector
  • 2 Red connectors
  • 2 Beige clips

TIP: It is hard to snap a rod into three connectors at once, try spreading the connectors out along the red rod so you only have to connect one at a time.
leftrightconnect2.png leftrightconnect3.png leftrightconnect1.png centerorangecut2.png centerorangecut3.png centercomplete3.png centercomplete2.png
Step 4
  • 47 Yellow connectors
  • 3 Gold connectors
  • 9 Green connectors
  • 4 Red connectors
  • 36 Orange connectors
  • 36 Yellow rods
  • 63 Blue rods
  • 72 Green rods

redyellowlayers.png orangelayer.png
Step 5

Temporarily remove the beige clips attached to the yellow beam on the center of the spring. This will allow you to shift the connectors snapped onto it around, making it much easier to connect the layers.

NOTE: Make sure the gold track guide layer is the center layer, connected to the gold track guide connector which you cut earlier.


layerorderbottom.png layerordertop.png bodyspringconnect1.png
Step 6
  • 2 Yellow connectors
  • 7 Red connectors
  • 9 Orange connectors
  • 11 Dark gray connectors
  • 4 Beige clips
  • 2 Yellow rods
  • 6 Blue rods
  • 18 Green rods
  • 2 Black rod/connectors

backendwallparts2.png backendwallparts1.png triggerskeleton.png
Step 7
  • 3 Dark gray connectors
  • 3 Red rods
  • 3 Black rod/connectors
  • 15 Silver spacers
  • 6 Blue spacers

triggerslidebar.png triggerskeletonandslidebars.png
Step 8
  • 7 Orange connectors
  • 12 Dark gray connectors
  • 5 Beige clips
  • 4 Blue rods
  • 10 White rods
  • 2 Hinges

fingertrigger1.png actualtriggermechanism1.png fingertriggerattachmechanism1.png fingertriggerattachmechanism2.png fingertriggermechanism1.png fingertriggermechanism2.png
Step 9
  • 3 Blue spacers
  • Rubber band(s)

TIP: Experiment with rubber bands to find what works well for you. I personally prefer two #32 rubber bands (3-1/4" long when flattened, 1/8" wide) Note the black connector/rods connecting to the white rods in the second picture. triggermechanismslidebar.png triggerslidezoom1.png triggermechtopoffrubberbands.png
Step 10
  • 3 Orange connectors
  • 2 Beige clips
  • 1 Yellow rod
  • 8 Blue spacers

hingeguide.png triggertopguides1.png
Step 11
  • 2 Green connectors
  • 3 Orange connectors
  • 3 Dark gray connectors
  • 2 Beige clips
  • 1 Yellow rod
  • 5 Blue rods
  • 3 Green rods
  • 8 Silver spacers
  • 9 Blue spacers

NOTE: Remember to connect the dark gray connectors added here to the ends of the blue rods from the finger trigger.
midbeamsupport2.png midbeamattached.png
Step 12
  • 2 Orange connectors
  • 6 Dark gray connectors
  • 4 Beige clips
  • 1 Yellow rods
  • 4 Blue rods
  • 2 Black rod/connectors
  • 2 Chain links
  • 10 Blue spacers

Make sure the chain links are oriented correctly. When it is in place (as seen in fourth picture), the hooks should be facing up.
triggerreleasesolo1.jpg triggerreleaseattach1.png triggerreleaseattach2.png releasehingeattach1.png
Step 13
  • 4 Yellow connectors
  • 1 Gold connector
  • 4 Red connectors

triggerbodyconnectposition1.png addingyellowredgoldconnectors.png triggerbodyattachbottom1.png triggerbodyattachbottom2.png
Step 14
  • 16 Beige clips
  • 8 Yellow rods
  • 13.5" Orange track

pins.png pinshalfin1.png pinsin1.png pinscomplete1.png trackon1.png
Step 15
  • 40" of string (any string that isn't too springy, I use fishing line)

rightstringanchorspread1.jpg rightstringanchorthreaded1.png crossbowfrontcomplete1.png
Bolts
  • 2 Purple connectors
  • 2 Light gray connectors
  • 4 White rods
  • 4 Blue spacers

bolt1.png bolt2.png bolt3.png bolt4.png

Done!


loading.png loading2.png loaded1.png loaded2.png triggerpulled.png