Jigging Tubing Before Weld

[Cothron Theiss]

Originally Posted by SerpentEagle

I'm looking to eliminate the need for gussets on many places on the robot next year, hopefully cutting fabrication time down by a good amount. I was wondering how teams jig together their frames prior to welding (other than using gussets). A good example that I could think of would be 254. Any ideas?

Ok, so why exactly are you wanting to do away with gussets? In a lot of cases, gussets can be stronger than just a weld and if you want to change something or you need to remove a tube, gussets can taken off and re-assembled at a competition. I'm not saying welds are bad, just making sure you consider the pros and cons.
Also, many teams assemble their tubing with gussets and weld the gussets onto it. That ends that whole quick modifications thing, but it's a great way to do fabrication.

As for your actual question, there's tons of different ways to do jigs. I assume you're welding square and/or rectangle box tubing and not round tubing. The more you can know about what you're welding before hand, the easier you can make your jigs to use. You can make just a flat plate with pre-drilled holes. Use the holes to clamp down and/or insert pins to locate the different parts. You can set the pre-drilled to the angles you might commonly use, like 15, 20, 25, 30, and 45 degrees. You'll have to figure out what angles you'll want to use. It depends on what kind of tolerances you want to hold, and what equipment you have. Do you have a mill? If you can put some time and effort into the jig, you can get very tight tolerances on the angle itself.

Originally Posted by s-neff

On the Mini-Baja race car team in college, we ended up designing 3/4" particleboard jigs for the tube chassis with waterjetted cutouts in the exact design locations for each tube, and laying everything out before welding. It helped that we were using the same particleboard that our tube sponsor packaged the pieces with for transport (free), and that our waterjet time was free from the ME department in return for help with the upkeep.

I'm working on making jigs for our car this year. We often spend more time on the jigs than the welds themselves, especially when the angle of the weld is especially critical.