I often use computer on big TV from my sofa. For that purpose I always keep my second keyboard and a trackball near my sofa. This simple small table for sofa armrest gives the keyboard and the trackball their own dedicated place. 

The model is parametric, so you may adjust dimensions of the table to fit your specific needs and use it for an ebook reader, a tablet, books, etc.:

• width (default 102mm) - width of the armrest (= inner distance of the table legs)

• length (default 140mm) - length of the table

• depth (default 100mm) - depth of the table on the inner side

• sidePocketWidth (default 22mm) - inner width of the pocket (= usable width)

• sidePocketDepth (default 150mm) - depth of the table on the outer side

To modify the parameter values, open attached f3d file in Fusion360 and go to „Modify“ -> „Change Parameters“. Attached STL file uses the default values listed above which I use in combination with my Logi MX keyboard and trackball.

No supports needed.

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UPDATE 12.04.2026

I added second model which has magnets embedded into its top surface (“Armrest Table with Magnets.f3d”). This way you can easily add additional holders on top of the table with some specific function, e.g. cup holder, snack holder, TV remote holder, etc. Original model "Armrest Table.f3d" is unchanged.

You will need 8 magnets – four for the table, and four for the tabletop. Each magnet is placed in the corner of the table; the center of each magnet is located 2cm from the closest edges of the table (see attached diagram).

Since the first model was already parametric, I added new parameters to define magnet size as well, so that you can use magnets of your choice:

• magnetDiameter (default 10.5mm) – diameter of the magnet; value needs to include tolerance so that you can insert the magnet

• magnetHeight (default 2.3mm) – height of the magnet; again, value needs to include tolerance so that you can insert the magnet

• height (default 8mm) – height / thickness of the top flat surface of the table. In case you decide to go with larger magnets, you may need to increase the thickness of the table so that the magnets will fit inside.

I used magnets of size 10x2mm as you can see from the default dimensions above. The connection is strong enough to hold small items. If you plan to use larger or heavier items, I recommend going with stronger magnets.

I also included a tabletop with a cup holder (located in the same file “Armrest Table with Magnets.f3d”). There are two variants included – one smooth and one textured.

The tabletop uses same parameters already defined for the table so that it is of the same size, and additionally adds several new parameters for the cup holder function:

• cupRecessDiameter (default 80mm) – diameter of the recess to hold the cup

• cupRecessDepth (default 4mm) – depth of the recess to hold the cup

• tabletopHeight – height / thickness of the tabletop. In case you decide to go with deeper recess to hold the cup, you will also need to increase the thickness of the tabletop.

 You may design your own tabletops with whatever function you need, just add magnets to its bottom so that you can attach it to the top of the table.

When slicing the model, don’t forget to add a pause so that you can insert the magnets into the print. And when inserting the magnets, pay attention to their magnetic orientation, so that the tabletop is attracted to the table, and not repelled. People tend to mess that up.

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