Aluminum flat stock-1/8" is plenty
Rivets (varying in size)
Rubber bungees for securing. Otherwise extra tabs can placed to secure box to frame
Cordless Drill and bits
Angle grinder and cutting wheels
ear and eye protection
high speed air tool and attachments
Step 1: Cut Tabs and Box Body
Pictured are the tabs bent to 90 degrees. I used about 14 (mostly because I mis-measured the panels a number of times). They can be as narrow or wide as you like.
Once the tabs are cut, begin measuring the frame for the panels. If you are good and smart, you should only need to make two cuts for the whole box--plus the slot cuts to bend to 90. Obviously, I reinforced my panels with some riveted tabs. NOTE: Add some to the inside of the box to maintain rigidity. You will know if it s not strong enough when you go to strap it to the frame using your rubber bungees and the box gives too much and distorts.
NOTE: The key is to mount lower on the frame then is pictured: the rubber mounting system requires a two stud-flanges that resist against down tubes and secure the box to the frame.
Step 2: Rough Mounting
Once determined, the rubber mounts can be riveted to the box. I riveted underneath and strecthed the rubber around the tubes and secrued them using extra tabs to catch the rubber at the top. This is where issues can arise, since all seats are not created eaqual and will sit lower on teh frame and against the top of the rubber strap, causing a rocking sensation (and not the good kind).
Step 3: Finish Mounting and Routing
Since the wires exit the frame where the box is mounted, the box covers the wires from exposure to the elements and limits any unruly behavior. Taillights and flashers can run along the downtubes.
And there you have it--one way to (relatively) tame the wildness that are 70's Sportsters.