Step 1: The Beginning!
1) Measure from the rack securing tabs to however high you want the rack to sit above the wheel, mine sits about 3in above the wheel. This will be your main support.
2)Decide how long and wide you want it. Mine is about a foot long by 4in.
3)Find your materials, for the main support I used half inch square stock, originally the whole thing was made of 8th inch rod, but it was to skimpy. All the supports are 8th inch rod, and there's a piece of mesh stuff on the top to keep pack straps from flying into the wheels, Pick your materials according to what you want out of your rack, and your tools, for example if you want an extremely light rack and don't have a welder use aluminum and bolt it together. In addition you'll need a hose clamp and a couple inches of half inch flat stock, if your attaching it the way I did. And of course you'll need nuts and bolts for the tab things. Anything else you think you'll need go ahead and grab it.
Step 2: Throwing It Together.
2)Lay out the 2 pieces you just cut, then measure the part that would make it a triangle, I start a few inches from where it attaches to the tabs, and about 2 inches from the end of the top piece.
3)Get your welder out fool around with the settings and test it out. Once your welder is making nice pretty welds tack 2 triangles together, When your done you should have 2 pieces similar to the one below.
4)Now cut at least 3 cross pieces, and tack the 2 triangle pieces to the table the width of your cross pieces in one spot, so its easier the remove it from the table. Then tack the cross pieces in and remove.
Step 3: Reinforcement
1)If you used 8th inch rods like me, Cut 6 pieces about 3in long and tack them in each corner.
2)If your using something to cover the top, put it on now. The stuff I used works nicely for attaching milk crates.
3)Drill a hole the size of the hole in the rack attaching tab, in some flat stock, cut, then weld to the bottom of the main support. Then round up the flat stock, bend the frame out a little test if it fits pretty well, weld it together nicely then bolt what you have to the frame.
Step 4: Attachments
Take a piece of rod thats somewhat bigger than the 8th inch bend a 45 at the end and measure from the side of the rack thats closest to the seat post, to the seat post and cut the piece with the 45 in the end that length. tack it to the end with the 45 to the rack
bend a 4 in piece of flat stock into a 45 then hose clamp it to the seat post, get someone to hold the rack how you want it to sit, then bend the rod coming off so that it sits on the 45 on the seat post. Now weld the piece coming off of the rack to the 45, and make a nice beefy weld on the rod with the 45 connected to the rack.
Go through all your welds and make sure they're all nice and beefy, and make sure the bolts are on tightly.
when putting on the bolts put some type of glue over the remaining threads that are showing after you put the bolts on.
Step 5: The End!
Rejoice! you've just completed your very own bike rack!
Please leave questions, comments, and constructive criticism.