Give it a few light passes with a rat tail file. If the front and back leg from your photo move together you need to be precise about it such that the pins on the legs reach the end of both slots at the same angle.

Hi,

Ok you got the right idea, but where you show to remove material we actually have to add material. That will make it tight. I tried sticking some things in there but it's difficult because there is very little space to stick things in from the front or back. Like a twist tie from a bread bag, which does not work well enough. I would try a tie wrap but that won't fit in there.
I'm wondering if a larger hose clamp might help somehow because the leg is tubular.

I calculated the change in length but it comes out too large for what I am seeing. The first calculation came out to around 0.3 inches but it can't be that large. Maybe 0.1 inch but it could be as small as 0.05 inch.
That might be big enough for a small wire tie wrap, but the rivet head gets in the way so it can't be threaded into the end of the groove.

I am now thinking of making it permanent, but I hate to do that because it folds up nice and small for storage the way it is now.
I would not even worry about it too much, but if I have a full cup of coffee on the top of the table and the table shifts, the coffee will slop around just enough to spill over. Dang designers
Then who wants a table that rocks back and forth anyway even if nothing spills.

 

Ok you got the right idea, but where you show to remove material we actually have to add material. That will make it tight.

Credit to Alec as it's his idea. Whether you make the angle acute or obtuse, in both cases the vertical "component" of the leg will get smaller. With an acute angle the table would be inherently unstable and fold when it's on a slippery floor. Thus I would favor an obtuse angle. Plus it's easy to implement.

 

Credit to Alec as it's his idea. Whether you make the angle acute or obtuse, in both cases the vertical "component" of the leg will get smaller. With an acute angle the table would be inherently unstable and fold when it's on a slippery floor. Thus I would favor an obtuse angle. Plus it's easy to implement.

Well the image was draw just to show how the angles work. The leg actually does stick out at the bottom not inward. I just started drawing and didn't want to change it later.
I can update it though today sometime. I'm glad you mentioned it now I am more motivated to correct the drawing. The math should turn out similar though.

 

Hello again,

I got an idea from post #16 by 'hrs'

In the image, the left side drawing 1 is the starting triangle with the rivet at the very end.
Drawing 2 is after the table top is pushed to the right and held there. If I let go it goes back to #1.
Drawing 3 is after the push and also held there, with a bolt (red) stuck into the slot and tighten up. The bolt head is shown as a red circle.

This might work I just have to see if I have a bolt big enough for this. I think a 1/4-20 or better yet 1/4-28 might work.
It seems that if the bolt is in there with the head hitting snug up to the rivet head, when I let go of the top it won't be able to slide back to #1 positions and thus hold it steady.
I haven't tried this yet but it does look like it will work. Now to find the right bolt laying around
Might take a hardware store trip unfortunately.

The math turned out to be not too bad.

 

Hello again,

Well, although the bolt and nut would work perfectly in theory, in practic there is still a tiny amount of slop beacuse it is almost impossible to get it tight enough up against the rivet. What would be needed is something like a block of metal bolted to the brace, then a second screw going horizontally so it moves closer and closer to the rivet as it is turned. That would allow me to get a tight fit between the end of the second screw and the rivet head which would reduce the slop. It has to be very tight to be effective. Probably required on all four braces.

After this I might just give up and buy another non-folding table.

I can use this for something else and since I already had company and we used this table and it worked sort of ok, I can wait to get the new table too. We don't fill our coffee cups right up to the brim anyway ... well, that's unless we want to turn it into a coffee table