This Instructable shows you the basic steps of how I modified a 2 x 4 basics workbench (available on Amazon for $66) to serve as a portable table with a large open space underneath it. This is where I store my portable table saw when it is not in use.
Step 1: Obtain Parts, Determine Key Dimensions, & Build
Obtain the 2 x 4 basics kit (Hopkins 90164) and get the casters that you want to use.
Determine your key dimensions - width, depth, and height. In my case, the width is approximately 75" and the depth is 37".
I wanted the table to clear the table saw (with fence attached) by at least 1/4" - so I had to design the table so that the bottom of the front 2 x 4 cross member was 39-1/4" from the floor.
This meant that I needed to add a spacer assembly at the bottom of the workbench to raise it up.
Build the 2 x 4 workbench to the desired depth and width (the height is fixed) but leave out the two front bottom cross members (but be sure to include a short 2 x 4 piece to fill in for where the cross members would have been).
Then place the assembled table on the floor and determine how much it needs to be raised (including casters) in order to clear whatever you want to put beneath it.
In my case, I cut four pieces of 1" MDF for each side. I glued and screwed two of the pieces together and then drilled and countersunk a hole in each corner to allow a bolt to go through the two pieces and then through the foot of workbench and then through a small piece of wood, and then secured the assembly with nuts. It's hard to tell from the photos, and I didn't take pics of this when I assembled it. I glued two more pieces for each side and then attached then to the ones already attached to the base of the workbench with long screws. I then added the casters.
I also added pieces of wood with pocket holes to the inside of the top to allow easy securing of the top pieces. I used two different pieces to build the top, but at some point I'd like to replace them with one piece.
After assembly, make sure that you have the required clearance underneath (and adjust as required).
Step 2: If Desired, Add a Toggle Clamp ...
Now that you've got a portable table, you may find that the casters allow too much movement.
I added a small piece to the top of my table and attached a toggle clamp to the wall.
When I am finished using the portable table and want it to be stationary, I just roll it up to the wall and secure it in place with the toggle clamp.
This portable table serves as a great storage place for my portable table saw and allows me to use the large work surface for various projects that I'm working on.