Scioly.org

retired1 wrote:If your bracing is on the outside, you will have more glue contact area.

Consider building the two sides on a wax paper covered template. If you use foam under the template you can use grip pins. Push pins work well, but it is harder to get more than one use out of them because the pin is much wider. If you use steel under the template, your balsa can be held in position with small magnets.

No, that wasn't my question. I'm wondering how to construct the jig to connect the two sides together. I already created the two sides.

Is it triangular or rectangular or U Chanel shape??

For rectangular you can rip a piece of wood to the correct dimension and glue your bracing on the top. Then turn it over, rip another piece of wood the correct size and glue those braces on. On the towers, we used pieces of foam board in an inverted U shape to hold the sides in against the wood center. They could be easily moved and were stron enough.

Take two triangular blocks or two textbooks, set them apart by the distance you want.
Tape the two trusses on the insides of both blocks then slip a sheet of paper underneath that has the bracings drawn fullscale. This should help you with constructing the compression-compression bracings for connecting the boomilever.

http://nexote.net/nexote/Science%20Olympiad/
2009-2010, Entry 7 has a video that shows what I mean toward the end.

What should I build my base out of? My base is made of bass laminated by thicker balsa on both sides. Whenever I drill the base, usually the wood shears along the grains, and it splits. I tried using Aia's Boomilever Guide to make the base and It says that there are supposed to be two triangles on either side of the tension stick And the base is supposed to be a small hole from one side, and a larger hole in the back. I understand the reason why the two triangles, to act as anchors so that the tension is secure, but should the triangles be cut at a specific angle or in other words, what should be fine tuned to meet what object's requirements? Am I doing something wrong or what should I change or do?

Why did you decide to laminate with thicker material? There was a lot of discussion on what to do with the base on the Boomilever B/C thread, probably worth review. Also, when you drill, make sure there's a piece of wood behind what you're drilling(scrap wood) to stop the wood from splintering when the drill exits the base.

Okay. btw, how do I cut the triangles ? Whenever I cut bass with an x-acto knife, it always breaks or cut at a bad angle. Should I use bass sheets with this or just the 1/8 x 1/8 stick?

Yes, do back and read, as iwonder suggested. For the plate, for stiffness, so it doesn't bend/break at the bolt, you want thick, light balsa, with laminated, thin "skin"- at least on the away from wall side- recomend 1/64th on both the toward the wall and the away from the wall sides. The thickness (recommend 1/2 inch) also gives you the glue area needed, and space/distance for the triangular wedges Aia describes/shows.
These wedges should be out of the same material as the tension members- if you're using 3/32nds bass, which is more than enough, then the wedges shoulb also be from that. A good, sharp single-edge razor blade works fine. Angle of the cut is not all that critical- a good tight fit is

YES. Thank you, that completely answers the question. I wasn't sure if the triangles were there as wedges, or for correction

UQOnyx wrote:YES. Thank you, that completely answers the question. I wasn't sure if the triangles were there as wedges, or for correction

Cool. The way Aia's using them, they act as wedges

One more thing: What wood sheets should I buy for the base? I'm going to get them right now so I need them quick