Introduction: How to Tether Your Thumb Drive Cap

About: If there's one thing I've learned about being an adult, it is this: there's always another project. Over the years, I've tackled a ton of projects and built some cool stuff, and now I'd like to help people wh…

My Corsair GTX thumb drive is a very robust device with a hard, aluminum exterior. However, there is no attachment between the cap and the body of the thumb drive itself, so losing the cap is a very real possibility. In this short Instructable, I go through the process of adding a secure steel wire tether to connect the cap to the thumb drive body, removing entirely the risk of losing the cap.

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  • Thumb drive with non-attached cap (Corsair GTX in this case - note that this tutorial will not work with simple plastic caps since there's no place to drill through)
  • 8 inches of steel wire, thin gauge (1/16" or thinner is ideal, plastic coating preferred)
  • (2) cable ferrules


  • Drill (drill press makes things a bit easier)
  • Drill bit to match wire size
  • Wire snips
  • Hammer
  • Something to use as an anvil
  • Center punch (optional, but recommended - a tap with a sharp point can also be used)
  • Pliers (optional, but recommended)

Step 1: Mark and Drill Cap

A thumb drive with a cap very tight to the USB port will not work using this method.

My thumb drive happens to have a cap much wider than the USB port, and it also has a rubberized filling taking up the extra space in the cap. Choosing a location to drill in this instance was very simple. I marked a center point for the drill bit, which is simply to keep the bit from wandering at the start of the cut. This is recommended, but not strictly necessary.

After marking, it's a simple matter to drill through the cap and clear out the hole. Choose a drill bit that will allow the steel wire to pass through, which is easy enough to do by checking that the wire fits in the bit's spot in the drill index. Drill where you marked with the center punch.

Step 2: Thread Steel Wire and Crimp to Cap

With the drilled hole in the cap, thread the steel wire through the hole and loop it back on itself. Insert the ferrule at the short end of the wire, and pull the long end of the loop through the other end. Depending on the wire and ferrule, you may have to ream the holes in the ferrule so that the wire can pass through. This is easy enough to do with a drill while holding the ferrule with a pair of pliers.

Even up the loop to your liking, then use a hammer to flatten/pinch the ferrule closed by pounding it on the anvil. This should fasten the loop on the cap side of the wire.

Step 3: Thread Steel Wire and Crimp to Thumb Drive Body

Before threading the wire, slip the second ferrule on. On the thumb drive body, loop the free end of the steel wire through the lanyard hole. Replace the cap on the thumb drive so that you can properly measure the length of wire required. Thread the wire through the ferrule, and check that the cap is easy to remove and replace - if not, add some length to your tether. Repeat the steps above for crimping the ferrule and trim any remaining end of the wire.

Success! Now you won't lose the cap to your thumb drive!

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