Tired of walking your bike past empty parking spots just looking for a rack to lock up your bike? Well now through a small re-appropriation of public space and a few junked bikes, you can be the difference you wish to see in your town.
Step 1: Scoop Up a Couple Old Bikes
Find two old bike frames. Check the Craig's list free section, your local bike kitchen, friend's garages, drainage ditches, bushes, or wherever else free bike frames are to be had.
Step 2: Cut Back Off of Frame
Using a hack saw, or if you are luckier than me, a metal cutting band saw, cut the top tube and the down tube of your frames where they connect to the seat tube. This leaves the rear fork triangle thingy. Find somebody that needs the front of the frame for their other sweet project.
Step 3: Grind Frame Flush
Grind and brush the front of the seat tube so it's flush and clean for welding. The tube that the pedals go into needs to be cut down so the seat tube is flush all the way down. Grind and brush that too so there aren't any nasty burrs left over.
Step 4: Scavenge Some Angle Iron
Find two length of angle iron that are no longer than the seat tube on either of your frames. The angle Iron should be large enough to fit around a sign post, about a two inch flange.
Step 5: Create a Hinge
cut the middle third of one of the frames' seat tubes out. hold it back in place and shove the seat post down through the tube, holding in the middle third of tube while allowing it to rotate freely. This will be welded as in the picture, allowing the welded attachment to rotate.
Step 6: Weld It Up
Weld the flanges to the seat tubes at a right angle, with the flange coming out to the left when looking from the top, with the fork between your legs, see the picture for clarification. This applies to both frames, so they line up when flipped. The flange welded to the frame with the hinge should span over the freely spinning section of tube and be welded on the ends. Now weld the free edge of the flange on the non-hinged frame to the middle section of the hinge on the other frame. this should be welded in line with the frame. You should now have two frames that are hinged at the connection, allowing the whole shebang to be wrapped around a sign post.
Step 7: Weld on Flanges for Ultimate Lockage
weld some plate with a hole in it to the last free flange edge and to the opposing seat tube. The hole should be big enough to shove a sturdy pad-lock through.
Step 8: Set Up Discreetly
p.s. you may want to use a better lock, I doubt my high school locker masterlock will last long.