Making Radio Box Keys
All radio box keys aren't the same. The tumbler arrangement can vary from box to box. I suspect there are many different tumblers available and 4 are used in each lock, and they can be arranged in different orders in a given lock. In fact, you can arrange your tumblers any way you want to as you make the key.
It's possible to make your own key or have a locksmith make one. The best locksmith in my area could do it but said it would take several hours and he would have to fabricate the key blank......mucho $$$$$$ however.
You can make one. Here's how I made mine. I can't give dimensions because your lock and tumblers will be different, but here's the procedure.
Take the locks off. Carefully take the back cover off of one. Care is required because these locks have some spring loaded parts and you don't want the pieces to fly away. Remember how the pieces fit, of course.
Making the key:
The shaft of the key is about 5/16" diameter and has to have a hole drilled into the key end. Use your lock as the pattern to determine the hole size. I used a round steel spacer that already had a smaller hole drilled and tapped into one end. It's easier to enlarge a hole than to drill an original! But, do the following welding first:
The flange (for lack of the proper word) which has the notches which activate the lock tumblers is about 1/8" thick. I cut mine out of a steel washer that was the right thickness. Roughly estimate the size by examining the lock dimensions. Weld this on the side of the end of the shaft. Then drill out the hole in the center. Otherwise you'll be welding a hollow tube and it can distort (voice of experience!). File down the weld to make it neat looking and to fit the lock.
The ring at the handle end of the key was made from a 1" chain link, welded on. Overall length of my key is about 4". My family calls it the "castle key". Sure doesn't fit in a pocket very well!
You'll find the following parts in the "key" area of the lock (with the back off, looking in):
1) In the bottom, a flat plate a little less than 1/8" thick which does the actuation of the lock mechanism. The first notch/flat on the key pushes on this to move it up or down. File the end-most flat on the key to make this work. (Work in two dimensions, length and height of the notch. Round the outer edge of the plate for constant radius as it rotates around the locating pin.)
2) Four flat plates that are the "tumblers". Note that they each have to be pushed a specific distance to clear the lock mechanism. Push them too far or not far enough and they won't work.
3) File the second "flat" on the key to match the position the bottommost tumbler has to be in to allow the bottom plate to slide. The key will now actuate the bottom mechanism and the first tumbler.
4) Continue by filing the key flats for the next tumbler, etc, until the last flat is cut.
5) File the flange/blade to fit the remaining thickness of the inside dimension of the lock with the cover back on and you're ready to make another one! The second key is much easier!
Good luck, and drop me a
if I wasn't clear on any of the procedure.
Bob Ragain Littleton, CO '65 404 softtop radiobox "HamMog" WB4ETT