The top is 400x400mm (~16″ x 16″) and 200mm (8″) high. The box is made from 18mm MDF, with a 4mm hardboard top (smooth side up). Everything is glued (Titebond III) and key parts, such as where the guide attaches to the box, are also screwed.
I’m using a Ryobi 600W jigsaw that I purchased specifically for this project for around US$80. The foot of the jigsaw has been completely removed, and I’ve bolted the jigsaw directly to the underside of the table using the bolt hole for the foot. A couple of blocks either side of the jigsaw are there just to keep it aligned.
I pulled apart a very old Black & Decker jigsaw and used the blade guide wheel from that as the new blade guide for the table.
The build took around 4 hrs (mostly waiting for glue to dry).
My experience after a bit of use is that this tool is great for cutting thinner (12mm or less) thicknesses of timber, but it feels pretty dangerous when cutting metal. I’ve been cutting 3mm aluminium plate, and I would not recommend using the jigsaw table for that. The blade wants to try and lift the work piece from the table on the up stroke, and I had to hold the work piece down very firmly and be extremely careful when cutting. This doesn’t seem to be as much of a problem with timber.
Secondly, this model of jigsaw (Ryobi 600W 85mm, RJS850-K) allows the blade to twist/rotate quite a bit. My battery jigsaw (Ryobi +one) holds the jigsaw blade absolutely rigid, but due to a different locking mechanism, this particular jigsaw model allows the blade to twist by up to about 30 degrees! If you’re planning to build a table like this, look for a jigsaw that holds the blade absolutely rigid.