Quote:
Originally Posted by Qbranch
Watch out! 
We tried this stuff and it does look fantastic on paper, but they have a huge issue with being out of square. Well, not the connectors themselves, but what you put together with them. When we tapped our connectors in everything was nice and strong... but horribly out of square.
The robot frame we put together couldn't even hold an axle straight, let alone sit level. Maybe if you used force gauges or something when pressing the connectors in, or had really close tolerancs on the ID of the tube you use it would work... but just a heads up, with your ajax square tube it doesn't look too pretty... 
-q |
Thank you for the info--I too was hoping that by mentioning EZ Tube,
somebody had to have seen it and tried it. Yes, I would imagine that in order to get a box frame that was square, you would have to have the opposite tubing pieces cut with 90 degree squared ends and be very accurate on the lengths since the lengths are controlled by the connectors bottoming out against the ends of the tubing. Keeping it squared up could probably be helped with some thin aluminum gusset strips and rivets, but now it's not so EZ.
Now that I've had time to look, the 80/20 system and the EZ Tube system look very similar, at least in concept, even with the availability of extruded tubing with panel-mounting flanges. EZ Tube connectors seem longer and have the option of the steel-core reinforcement (probably adds too much weight for a robot frame...probably).
Of course, if you're not worried about reusing the connectors, you could always use standard thin-wall 1" tubing and some two-part epoxy like JB Weld.