Karl,




See my post above. I was too lazy yesterday to look for a pic with the F16 version of these stocks.




In short, too heavy and too expensive. Lots of alu waste and owning such a CNC machine costs too. The square tubes come standard and all that is needed is a less expensive bending machine. There is no waste and the tubes are hollow which makes them both strong, stiff and lightweight. I think catamaranparts is welding them and that is a skill, but I've personally made 3D alu objects using aluminium glue and (monel) rivets and that seems to work very well too.

The rivets (or bolts) prevent the glue from being broken by a force splitting/leveraging the components apart, while glue handles all shear force and takes care of all play. If the contact surface is large enough then the glue can handle quite alot of "pulling apart" force as well. It can hold 160 kg per square cm. and that translats to 2279 lbs/sq inch.

My Australian friends told me that home builders used to make such stocks by hand over a hand made timber jig. I think one pours sand in the tube to prevent it from collapsing and just slowly bend it around a curved shape. One that is adjusted for the elastic spring-back.

Wouter