This is a scale model of the Trebuchet I hope to build with my son's scout troop this year. It is made with 6, 4ft dowels 5/8 inch in diameter. Using 1/8 inch jute twine for all the lashings, Only the launching plank is glued, all lashing are standard boy scout square lashings 3 wraps and 2-3 fraps each . There are many sites to show you how, look up the inside outside rule, this will make the lash as tight as possible. Each lashing should take about 4ft of twine,
It consists of 2 A Frames with dual support along with t buttresses / stanchions on each side to keep it from racking.
The throwing arm is 25 inches with a hole drilled at the 5 inch mark for a 1/4 inch steel bar, this arm currently support a counterweight of 10lbs. The throwing basket is duct tape reinforced with a piece of fiberglass cloth. The escape mechanism is made of a coat hanger and a key chain ring. As of right now I do not have a release mechanism (works fine by hand the full size trebuchet will have to have one).
Enough prep, onto the build
Step 1: Materials and Cutting
6 5/8" x 4' dowels (there is some waste about 2ft when I was done.
6 18" - 3 for each A frame, 2 for the frame and one for the lower support
6 12" - 2 for the upper A frame supports and 4 for the stanchions.
2 24" - Support base to hold up A frame and provide a base for plank
1 1 1/2" x 14" x 1/4" launching plank (mine was a scrap piece of molding)
1 25" - throwing arm
100' of 1/8 inch jute twine or alike each lash should take about 4 ft +
Head of Arm Release
4" from coat hanger
1 Old key chain loop about 1/2 inch in diameter.
~ 9" 1/4" steel rod
4 Nylon Washers
2 1/4" end caps
Duct tape multiple pieces:
5" x 2 in.
Fiberglass cloth ~ 5" x 2" to strengthen the tape.
Zip tie and electrical tape to hold Arm release.
Hand or Chop Saw
Pliers and Cutters
1/4 inch drill