If you'd like to replace your old, ugly, 70's coffee table with something a bit more interesting, you might wanna try just making a new top for it.
Sheet of Treadplate (cut to size when purchased)
4 lengths of aluminium extrusion
4 flightcase corners
Other stuff you'll need:
A saw to cut the aluminium extrusion
A metal file
Super glue (cyanoacrylate)
Step 1: Measure Up
Measure your coffee table so you know how big your treadplate sheet has to be and how long your aluminium sides have to be. Most places that sell treadplate sheeting will have the ability to cut it for you and I'd definitely recommend this as it will save you a lot of time and effort and probably give a nicer more uniform finish to your table top.
Do remember when measuring your extrusion that the size of the table will be the inside length of the extrusion, so allow for the additional thickness of the extrusion in your measurements to ensure a snug fit.
Step 2: Assemble!
Cut your extrusion with 45 degree angles so that they fit together to make a frame (this isnt strictly needed and you could of course simply have butt joints as the joins won't be visible) As the extrusion is L-shaped in cross section, it will provide an edge to the table and well as the mounting surface for the treadplate sheet..
To fix it all together, I'd simply recommend holding everything in place with gaffa tape on one side of the joint whilst you glue the other.
then wait a bit more...
Once the glue is dry, remove the gaffa tape and put the frame on the table.