This design can be far more simplified. There are some crossbows that rest the fiber of the bands in a notch on the wood. The trigger is a one piece of metal that lifts the fiber/s up and lead them on the back of the spear.
Here is a scetch i did right now. It is a little bit vague but i hope you will understand.
The design is tested and it is very acurate. Plus the spear has one and only hole for the cevlar string making it very powerfull in big fish. Also to mention that the direct contact of the bads/fibers on wood does not give the strength of just thousand pounds but as the piece of wood can stand. The shop that sold me the wood told me it can stand pressures up to 2 tons!
The sliding of the spear back and forth as also the rotatin in the groove is eliminated from the steel plate that lands in aspecial cut on the spear.
http://img.photobucket.com/albums/v3...s/speargun.jpg
Right now i am building one from beech wood at 110cm.
Edit: I haven't found yhe way to add a safety because i think of it right now but it shouldnt be that hard. Also forgive me for bad english it is not my first language.
