You can try this project out live on the Internet! It's at the TeleToyland Sandbox 2.
This is a second version of a previous Instructable, and is another approach to making a lower cost, lower precision XY table.
How easy is "ridiculously easy"? Here is a list of all the fabrication required:
1) For each of the six timing belt pulley brackets, cut 2.25" of channel aluminum, drill two 1/2" holes (pro-tip: use a step drill), and two 13/64" holes.
2) Cut 7" off the ends of two 1"x2" t-slot extrusions.
That it! The rest is like assembling an Erector set. Nuts and bolts. T-Slot is so cool! :-)
The previous approach is working well, but having the ability to easily adjust each of the parts is a great advantage of the T-Slot. Tightening the timing belts with screws in wood can be challenging to get just right, but with T-Slot it's very easy. While the cost is a bit higher by using bearings vs. drawer slides, we don't have the drawer slides sticking out like we do now, getting tripped over and caught in bicycle spokes. :-)
In addition to the T-Slot, we tried to keep the parts easily available (i.e. from home improvement stores), and as always, requiring the least amount of precision drilling etc. We've built a lot of projects, and anything that requires a hole to be drilled in a particular spot seems to be hard to get just right. We do have the tools - punches, drill presses etc., but it's just cooler to be able to use a hacksaw and hand drill! :-)
Here's a video of it in operation during testing: