Add an Ikea Alex Add-on unit to your Ikea Jerker.
Available for $50, it fits perfectly between a Jerker’s legs, and is even attachable beneath a Jerker desk shelf!
You’re making a sandwich. The top bun is the grey Jerker PARTICLEBOARD shelf, the bottom bun is the ALEX Add-On Unit, and in between is the steel Jerker STRENGTHENER (the part you bolt to the legs).
Colors in Line Art Drawings:
- Red – 2 felt marks on each side of the ALEX Add-on Unit for a total of 4 felt marks for lining up
- Green – Where you drill through metal in the STRENGTHENER, 4 times, and wood in the ALEX Add-on Unit 24 times.
- Blue – 8 Existing wood screw holes in the PARTICLEBOARD Jerker shelf
IMPORTANT! Before working on the real thing try, drilling and threading with a tap on some test materials first.
First, unbolt a shelf from your desk. Next, unscrew the eight wood screws holding the steel STRENGTHENER to the PARTICLEBOARD shelf. Keep these screws!
Next, line up the assembled ALEX Add-on Unit, upside-down, and flush with the front of the PARTICLEBOARD shelf so you can mark the locations of the existing wood screw holes on both of the ALEX’s sides with red felt.
Mark on the ALEX’s sides, where the outermost pair of holes are on the PARTICLEBOARD, for a total of four marks. Two on the left, and two on the right.
Now line up the marks on the left 
and right on the ALEX’s sides, with the STRENGTHENER’s holes. Make sure distances X and Y are the same or you will have a crooked set of drawers.
Now drill four small holes into the STRENGTHENER first and then through the ALEX’s top right after, not stopping. These four small metal holes need to be threaded with a tap to receive bolts. Be sure to keep these four holes hidden inside the drawers.
Also, each time you drill 
one of the four holes through the STRENGTHENER and ALEX’S top, stop and thread the metal hole with a tap. Then, re-drill the the ALEX’s top slightly larger so you have room to to push the bolt through wood to the metal thread without resistance.
Next, push a bolt through the Alex’s top and thread it into the metal STRENGTHENER. Repeat this step each time, so as to keep all the holes perfectly aligned.
Here we have the Alex attached to the STRENGTHENER with four black short threaded bolts. Now we need to drill eight holes through the ALEX so we can re-attach the drawers with the STRENGTHENER to the Jerker’s PARTICLEBOARD shelf.
Drill eight small holes through the 
ALEX’s top guided by the eight threaded holes in the metal STRENGTHENER when they are bolted together, four pairs of two.
IMPORTANT! Detach the STRENGTHENER from the ALEX before drilling the larger holes in the ALEX’s top.
To the right you can see four holes. The rightmost, the larger holes, being drilled through the ALEX’s top so that you can re-attach the STRENGTHENER to the Jerker shelf with the wood screws. This is a bottom view
Top view of Alex with all holes drilled out. Now re-attach the STRENGTHENER to the ALEX with the 4 small bolts so they can be screwed together with the PARTICLEBOARD shelf.
Use a magnetic screw driver, when lying on the ground, to guide the original wood screws through the large Alex holes, then through the 
smaller metal holes in STRENGTHENER, and finally into the original Jerker shelf to hold everything together. Two chairs work well to hold everything up in this front-on view.
With two people re-mount the newly built unit. Loosen all the side bolts on the Jerker legs to give space when fitting the new shelf in place. Here is a side view of a finished product.