I wanted a table that could be used for a laptop by the sofa. This table is made from two Lack tables.
Take a Lack leg. Cut a segment at one end two leg-widths in length. (If you’re using a saw with a wide kerf–I used a miter saw–then make sure that the kerf goes on the long side of the cut, so the short segment is as close to two leg-widths.)
Be careful cutting. Apart from MDF blocks at the two ends, the legs are hollow.
Repeat with three other legs. You will now have four shorter legs, and four short segments. Make all the legs as close to the same length as possible, e.g., by setting a stop on a table or miter saw.
The legs are hollow inside. Shake out the sawdust, and cut wooden block inserts (3/4″ softwood is what I used) to fit the hollow ends at the cut. You will need eight inserts cut and (if necessary) sanded to size. Glue them into the hollow ends, making sure that the inserts are flush.
The four short leg segments have the MDF with predrilled holes on one side. Attach that side to the underside of one tabletop with the standard two-sided Ikea Lack leg attachment screws, and do this for all four short segments. Make sure that the segments are all screwed in equally hard.
You now have a super-short Lack table! Place it upside down, with the “legs” (i.e., the short segments) sticking up. At the bottom (or top, when upside down) of each vertical segment you will have the wooden block you glued in.
Drill holes all the way through the second tabletop, about 1/2″ or 3/4″ diagonally away (e.g., towards the center of the tabletop) from the leg attachment holes. Put this tabletop upside down on top of the vertical segments from the first tabletop and align the tabletops carefully. Now, continue one of the holes you just drilled into the wooden block in the segment that is now under it, while keeping the tabletops aligned. Enlarge the top end of the hole to countersink your wood screw. Now run a wood screw through what you just drilled. This will connect the second tabletop (which will eventually form the shelf) to the short segment that is connected to the first.
You still have four legs that were shortened by removing the vertical segments from them. They have MDF blocks on one side, with Ikea’s predrilled holes, and your wooden inserts on the other. Connect the MDF block side to the tabletop with Ikea’s two-sided screws. If you’re putting it on a wooden floor, I recommend putting felt pads on the other side of the legs (the one with the wooden inserts).
If you like, you can say you’re done now. The resulting table with a shelf has an elegant Ikea-like look. (You can also make it a bit taller by using the uncut legs instead of the cut ones.)
However, because the shelf has no edges, stuff you put on the shelf can slide out. Moreover, any mess on the shelf is visible. For that, there is one more step.
I added raised edges to the by cutting the remaining four Lack legs to fill the space between the vertical supports on three of the four sides of the table.