This model is intended to be used on 8 inch square/flat armrests. Feel free to download and edit the .sldprt files for different widths of armrests (I think that should be possible?).

It was designed to be put together using six m4x20 screws and accompanying nuts. Longer screws up to about 30mm should work fine I think.

One of the more useful things that I have designed and printed, makes a nice place to put a drink, remote, phone or whatever. I printed in petg.

I printed all the parts in their most flat orientation, with the table top right side up and supports on (build plate only), the holes shouldn't need any support.

Also if it wasn't obvious, the “extra round” top and side match together, you'll have mismatched bevels otherwise.