I bought a desk without a sliding keyboard tray, and didn't realize how much I wanted one. After searching online for one, none of them really seemed like they were worth the money, and since I recently upgraded to a new printer, I figured it was a good challenge to see what I could make.

The bulk of the credit here goes to EasilyBuild for his "Airsfot Ball Bearing Drawer Slide" design. All I did to it was extend the slide by ~30% to get just a little more extension out of it while still being printable on a 220 x 220 mm bed.

For this project you will need:

• 24 6 mm airsoft BBs (I recommend eBay, you can get small bags of 100 for about $4)
• 8 #6 countersunk wood screws (for attaching to the desk. The length you need will vary depending on how thick your desk is, I used 1/2" long screws for my 19/32" thick desk)
• 8 #6 countersunk wood screws (for attaching the tray to the bearing slides. You can technically use any length screw here but I just used the same 1/2" long wood screws from before. You can also get away with just using 4 screws here)
• 8 M4x12 mm countersunk machine screws and nuts (or imperial equivalent)
• A rectangular piece for the "tray" of your choosing. I used an 8"x24"x5/8" piece of shelving made by Rubbermaid from Home Depot.

Follow instructions by EasilyBuild for the bearing slide assembly and the rest is pretty simple!