I only have my one road bike, and up until now I've always used it just for exercise, because wearing cleats to the store or other recreational destination wasn't practical. (I don't like tearing up my cleats by walking a lot in them, and if you ever walked a while with cleat covers, you know this isn't very fun either)
So since I had a little downtime (long, gross story) I decided to figure out a simple super-cheap design - something that would let me cruise to the ice cream shop or the park with the wife, wearing regular shoes. A trip to the home improvement store netted me all the parts I needed:
1 - 7/32" Drill Bit (5.52mm)
6 - 5mm Screws (w/ nuts and washers)
And I already had the other stuff:
1- 24" Carpenters Square
2 - Cleats of the appropriate type
Tools I used include:
Angle grinder w/ cut-off wheel
My main goal was to build as cheap as possible. Well, a pretty piece of aluminum (and even steel) was running $10-$15 or more, because you have to buy 3 ft. of it, nothing smaller was available (at least not without burning a bunch of gas going from place to place looking). As I wandered, I saw the carpenters squares - $6.00 for all the steel I needed, plus some. The bonus was I already had three at home, and one was a $0.50 garage sale score - so that solved that.
Screws and drill bit were $7.00 (and I thought I had a drill bit, but wasn't sure, so I got an extra to save a trip, just in case).
I clamped off the square in the vise and used the cut-off wheel to make 2 - 5" long pieces (just a guess on my part, but seemed about right) because I needed enough extra material for some leverage to yank them back off when not being used. You can use a regular saw as well, but if you got the tools, you got to use 'em!