Here are the steps to build a corner using the tube-and-gusset method. Click on the pictures to zoom in for a closer look at the *cough cough* fine workmanship.
1. Build the beams; see last post in blog for comments on this.
2. Line up the beams using a square edge. Chalk or pencil on the garage florr helps, and sliding a piece of Duct Tape under the corner, sticky side up, will help hold the angle prior to clamping or riveting.
3. Cut the gusset out of steel flashing material. Should be from relatively not-thin material; could be aluminum. The critical measurement here is the 90 degree corner of the gusset, and that is only to make the bending easier; the diagonal length, angles don't really matter as long as there is enough metal to actually act as a gusset and hold the corner together. Note when sizing the cut, the material should hang a good half inch over the edge since this will be folded down to wrap the edges of the beam, and then riveted.
4. Shape the gusset. Bend the edges over using flat pliers, a table edge, or your square sense of humor. The pliers shown here are made expressly for bending thin metal into straight edges; the mouth is about 3 inches wide. As should be self evident, these bends should be at a 90 degree angle; if gusset piece was cut to 90, you can use the marking on the edge of the pliers, or just measure and mark with a sharpie marker. A small cut will be needed in the corner.
5. Rivet gusset top. Three rivets per beam, or more but they should not be closer than a half inch fto each other. Note the sides are not riveted yet, that is done in the last step - not sure why I ended up with that habit but there you go.
6. Make the corner brace. This is made from a section of beam that has not been riveted together yet. Prepare to lose a about a quart of blood while cutting, sizing, fitting, and re-cutting these pieces. Note the piece's edge flaps will need to be flattened out where they will be slid under the main beams; while a hammer is satisfying, a pair of pliers will do just fine here. These corner pieces are roughly 10 inches long, the inner flaps that get folded 45 degrees are about and inch and a half here; the outer piece's flaps are shorter only because I was too cheap to cut a longer piece out. These flaps will end up with a rivet (inner) or two (outer) at the end of the day, so they need to be long enough for that, eh.
7. Fit the corner brace; prepare to do this several hundred times making small adjustments. Note the pieces are not riveted together just yet - you need to be able to slide them in relation to each other in order to get the 90 degree angle.
8. Rivet corner brace. Drill one hole, insert rivet (put do not pull rivet yet), drill furthest hole from the first one, insert rivet (but do not pull yet), repeat. Don't forget yer flaps, eh.
9. Drill and rivet gusset sides.
10. Gusset other side. When reverse side is accessible, build and attach a gusset to it. Remember to rivet the other side of the diagonal corner beam as well if you did not prior to installation. If both sides are accessible at the same time, or if you care enough to gerryrig the very best, you can make a "wrap around" gusset using an L shaped piece that has the elbow of the L riveted to one side, and the legs of the L wrapped around and riveted to the reverse side.
11. Repeat. About 63 more times, not counting mess-ups.
....and that's all I have to say about that.
