As soon as I assembled the tables, I encountered a problem. Once the tables were on the ground, they were stable. Getting them there was like what I imagine wrestling a baby giraffe is like—legs dangling and flopping around and getting in the way. It wasn’t that bad—I lived with the tables nearly nine months before doing something about it. 

 

I needed something equivalent to the hinged diagonal supports on my cafeteria tables. There wasn’t much room, and I didn’t want to fiddle around with hinges arms anyway. Simple locking pins (short rods with ball or T-shaped handles that go through holes in the legs and support beams) would have worked, but I didn’t want extra parts to worry about or misplace. 

 

In the end, I decided to add narrow lock panels to each side of the table. These lock panels are connected to the fixed leg support plates with piano hinges. When the table is closed, the locking panels lay flat. When I set up the table, I open the legs and flip the locking panels up so their front edges contact the backs of the leg assemblies’ top rails. (The panels’ front edges are beveled 10 degrees to match the leg’s splay angles.) 

 
 

 

Because I hadn’t designed this locking mechanism up front, some trial-and-error was involved in their construction. 

 

To save money, I bought two 48” piano hinges (one for each table) and cut them into 21” sections with a hacksaw. 

 

 

 

When I prepared to mount the hinges, I discovered that some of the screws holding the leg support plates to the support beams were in the way, so I had to relocate them. 

 

 

 

Now it was time for a quick test. I flipped the lock panels up. 

 

 

 

As I hoped, they held the legs open. The concept was sound.

 

But, as you probably suspected, I wasn’t finished. The panels didn’t press tightly against the backs of the legs, so it was very easy to dislodge (unlock) them. I needed a way to secure them. 

 

The answer was magnets. It took some experimentation to figure out how many I needed, but I ended with two 3/8” diameter, 1/8” thick magnets (surface mounted) on each lock panel paired with magnets on the connected support plate. 

(In the pictures above, you may notice an extra counterbore between the two magnets on the lock panel. That’s left over from my first test. I had initially hoped that a flush-mounted magnet on the lock panel would stick to the mounting screw head to secure the panel. It was far too weak.) 

 

The magnets hold the closed lock panels in place so securely I needed to drill 1” diameter finger holes to make it easier to open them. Unlocking the panel is a bit like picking up a two-holed bowling ball—thumb in one hole, index or middle finger in the other. 

 

 

I also added magnets to secure the unlocked (open) panels in place when the tables are closed. For this, a single matched pair of magnets was sufficient. These magnets are flush-mounted so the lock panels sits flat on the beams. 

 

With the magnets installed, the project was finally complete. 

 

You may be wondering why I didn’t do anything to keep the tables’ closed legs from flopping open when I remove or replace the tables from the storage bracket. Right now, friction does that job. The legs rub against each other when closed, and that keeps them in place. I don’t know if this rubbing will eventually wear away enough material to matter. If it does, I’ll have to “reopen the case” and devise a solution. But, for now, it’s not necessary.