Fabricating the tunnel for our prototype would have been pretty easy with an 8 foot long sheet metal brake. Since that isn't one of the tools we have at the shop, we had to be a little creative.
After making a flat pattern of the tunnel pieces in Solidworks, we added thin slots along the bend lines to "score" the material. The plasma cutter would cut these lines and leave small tabs holding the sides and top of the tunnel together.
In the following image the top piece is the tunnel and the bottom pieces are the "floor" pieces of the tunnel. The floor pieces have slots in them for the tunnel to lock into after the tunnel is bent.
The end result of cutting the slots was that instead of making a long bend all the way down the tunnel, we just had to bend all of the short tabbed sections. This helped in two ways:
No matter how straight we would have clamped the part to our wooden work table, the bend wouldn't come out straight if we were trying to do a full length bend. The slots made sure the bend ended up exactly where we wanted it down the whole length of the tunnel.
And no matter how strong we might think we are, there was no way we were going to make an 85 inch long bend in 14 gauge steel by hand. The material removed from the slots made it easier to bend. (Side note: we actually overestimated our strength and ended up cutting through every other tab with a cutoff blade to make it even easier to bend)
It still required some muscle but we were able to bend the tunnel on the edge of our table. After we set the bend angles with an angle finder, the tabs on the tunnel fit right into the slots of the floor pieces.
We tack welded each tab under the floor and had our first look at the backbone of the VeeDub ReDub platform prototype.
In the next post we'll start welding features to the tunnel assembly. Be sure to subscribe if you'd like to receive notifications.