Trebuchet of the large variety (a work in progress), 4.28.07 update

Step 2 Base: construction (I)

Let's build that base design (I) thing! Hah, I borrowed a little two-door Saturn to get to Home Depot and had to make three trips to get all the wood...sigh. It was fun though; I bought 16 2x6's to do the job (each is 8' in length). You are strongly encouraged to be more resourceful and find some scrap wood or make things less thick, whatever you'd like (that's going to be a recurring, cost-saving element in this Instructable, "be more resourceful than me").

Square the ends of your wood before you mark them (just cut off an inch or so from end, then measure from that freshly cut end). Mark the lengths and slice it up!

A quick cutlist (all parts come from 8' 2x6's):
legend: quantity of 2x6's should be cut to the given length
8 at 6'
4 at 4' 8"; 4 at 2' 9 1/4" (make these two pieces off of the same 8' 2x6 and repeat four times)
4 at 7' 4"

It may be handy to have the previous step, Design of base (1), open as you read this. I used 10d nail fasteners (they're 3" long) and some carpenter's glue to put the pieces together.

Construction of blue/purple sections (remember, blue = purple...I'll stop saying that) is as follows. You'll use a 7' 4" piece, a 6' piece, and a 4' 8" piece. Lay the flat ends of the pieces atop each other with the 6' piece in the middle. Go to one end of this component and align all the ends at the end..an awkward repetition of words but press on! If you align them, the other side of the three boards will become staggered at 16" forming something vaguely step-like. Fasten those suckers together; I put a good layer of glue and then drove two nails every 6" or so. Clean up the glue that comes out of the seams with a warm paper towel. That makes one component; repeat this three more times (you'll have four of the components at the end).

The middle, blue section with the slot will require two 6' pieces and two 2' 9 1/4" pieces each (we'll be making two of the blues). Start by putting a 2' 9 1/4" piece 16" in on one end of a 6' piece. Mark where this piece is going to be located before fastening so you can put the glue down carefully--this thing has a slot and glue should be kept out of that area opposite the 16" offset. Fasten that and then find yourself a scrap 2x6, there should be several somewhere... The 5.5" slot is the width of this scrap; set that in place then butt up the other 2' 9 1/4" piece against it, down the length of the 6' piece. Put down your glue and, with the scrap still in place and the small piece tight against it, nail it all together (er, but no nails in the scrap piece). The remaining 6' piece will go 16" in from the first 2' 9 1/4" in piece you put in during the last sub-step. The entire thing will form a sort of "jagged parallelogram." Hah, you'd likely be better off looking at the design photos than listening to my ridiculous descriptions. Repeat the blue section twice.

You should now be able to create an 18' long section of the trebuchet's base by aligning two of the "step" pieces with the slotted, "parallelogram" piece in between. If it's a bit off and things don't quite line up, it's not a big deal as the bolts used to hold the pieces of the component together can be placed anywhere in that overlap.

I'd love to hear some suggestions for improvement to the techniques in this section--I'm a half step above "novice carpenter" so I have a feeling there are better/more accepted ways to do some of this.