I bought my supplies from Lowes, but you can purchase them from any decent hardware store or home center. You will need to buy the following:
-3/16" metal plate, at least 2" tall, and at least 28 inches long. Steel will provide more stiffness, but will also add more weight. Aluminum may also be used if desired.
Be sure to get a bar that is straight, with no warping, twisting, or bowing)
-Spray paint for corrosion protection
-Furniture nuts, I used Lowes part number 148248 (Link)
-Furniture bolts, I used Lowes part number 148284 (Link)
Standard nuts and bolt heads are too thick to work for this project, and will interfere with the X-carriage. Additionally, there isn’t much area on a standard nut and bolt head, and the addition of a washer will only increase the distance they stick out. Furniture nuts and bolts are perfect for this modification because they are low profile and have a lot more surface area.
The modification was initially documented by Charley Thomas (attached to this project as a digital file), all I did was make minor changes to it to fit my situation and record a video with instructions.
Cut the metal plate to size, if necessary.
Remove wires from between the makerslides before installing the metal plate!
Although I used a drill press to drill the holes through the material, it is possible to insert the plate between the makerslides and drill all the way through while it is held in place.
Modify the directions in the PDF and video as necessary for your situation.