How to Build Your Own External Hard Drive

DIY external drives expand storage without the need to open the computer case

What to Know

  • To build an external hard drive, you'll need a drive, a case, and a screwdriver. This project will take takes about 10 minutes of your time.
  • You can repurpose older hard drives as new external storage devices, or you can buy a new drive.
  • Solid-state drives as well as traditional hard-disk drives can be made into external storage.

External hard drives are a great way to expand your computer's storage capacity. These drives are a good choice if you have a computer that doesn’t allow you to easily add an internal hard drive or swap current drives for larger ones.

What You Need to Build a DIY External Hard Drive Case

If you build your own external hard drive, there are a ton of benefits. You can choose the size of the hard drive and the type of connections you want on your case. You can also choose an external case that lets you use all of these popular methods of connecting an external enclosure to a computer:

  • A hard drive: This can be a drive you purchased for this project or it can be an unused hard drive from another computer.
  • An external case: External cases are available from retail and online sources. These cases include a power supply, an interface adapter, and a method of mounting a standard form factor hard drive (either 3.5-inch or 2.5-inch).
  • A screwdriver: Usually, a small Phillips #1 or #2 will do, although the size you need is dependent on the design of the external case.
  • About 10 minutes of free time: Yes, we really mean 10 minutes. This is a simple project. If you can wield a screwdriver, you can build an external hard drive.

You can purchase ready-made external hard drives. Just plug them in and go. But you pay for this convenience in two ways: in actual cost and in limited configuration choices.

Select an External Hard Drive Case

In the modern-day, selecting a hard drive case is easy. Aside from the physical size of the drive and what kinds of connections you want on the case, there isn't much to differentiate one case from another other than build quality, reliability, and ease of assembly which are often reflected by a product's reviews.

  • Select a case size: Standard internal hard drives use a 3.5-inch form factor. Laptops generally use a 2.5-inch hard drive. SSDs (solid-state drives) commonly use the 2.5-inch format. The case you choose should be designed for the physical size of the hard drive you plan to use.
  • Choose the external interface: The internal interface SATA has become the norm for hard drives, but external interface connections can vary. Common choices are USB 2.0USB 3.0, and Thunderbolt. Many external cases provide more than one connector, and most come with USB 3.0.

Select a Hard Drive

You either use a drive you currently own but don't use all that much, or you can purchase a fresh drive, saving money on a pre-built by assembling it yourself.

  • Note the drive interface: Your existing hard drive's interface must match the internal drive interface used by the enclosure you selected. Hard drives today almost universally use the SATA interface, so as long as your drive isn't ancient, and probably not worth using, this should match.
  • Check the drive capacity: If you don't buy a new drive, confirm your selected drive's capacity. Many drives include this on the label, but if yours doesn't, search online for whatever is written on the device, like a model number, to find the manufacturer's listing. Small capacity hard drives may not be worth installing a case on.
  • Consider how you will use the drive: If you plan on moving the drive around a lot, from house to house or room to room, consider using a solid-state drive over a normal hard-disk drive. Hard-disk drives have moving internal components that can and will be damaged if jostled too much while spinning, but solid-state drives don't have this issue.

Disassemble the Hard Drive Case

Each manufacturer has its own way of opening an external case to add a hard drive. Read the instructions that came with your enclosure to learn how the case works.

These instructions cover the traditional way to open a hard drive case:

  1. Set up in a clean and well-lit location: Prepare for disassembly by gathering the tools you need. A Phillips screwdriver is usually all that is required. Keep one or two small receptacles nearby to hold small screws or parts removed during the disassembly process.

  2. Remove the retaining screws: Most enclosures have two or four small screws located on the back and usually one or two on each side of the panel that holds the power and external interface connectors. Put the screws in a safe place for later.

  3. Remove the back panel: After you remove the screws, remove the panel that houses the power and external interface connections. This process usually only requires a little pull with your fingers, but if the panel seems stuck, a small straight-blade screwdriver slipped between the panel and the top or bottom cover plates may help. Don't force the panel, though; it should slip off. Check the manufacturer's instructions if you have trouble.

  4. Slide the internal carrier out of the housing: After you remove the panel, slide the internal carrier out of the case. The carrier contains internal interface electronics, the power supply, and the mounting points for the hard drive. Some enclosures have wiring that connects the carrier to a switch or display light mounted in the front of the enclosure. With those enclosures, you don't remove the carrier from the case, but only slide it out far enough to allow you to mount the hard drive.

Attach the Case to the Hard Drive

Hard drives traditionally may be mounted by four screws attached to the bottom of the drive or by four screws attached to the side of the drive. Another popular method is to combine the side mounting points with a special screw that has a rubber-like sleeve.

The assembly method you use depends on the drive.

  1. Install the screws: Read the included instructions and follow along carefully. It's usually easiest to install one screw and leave it loose, and then install another screw diagonally across from the first one. This pattern helps ensure that the mounting holes in the case and the hard drive align correctly. After you insert the screws, tighten them down by hand. Don’t use excessive force.

  2. Make any necessary connections: In-between the case and the hard drive there are two connections to be made: power and data.

Making the connections may be difficult because of space. Sometimes it's easier to reverse the order for mounting the hard drive. Make any necessary connections first, and then mount the drive to the case with the mounting screws. This sequence can provide more working room to get stubborn cables connected.

Put Your DIY Hard Drive Back Together

You've mounted the hard drive to the case and made the connections. Now it's time to button the case back up, which is a matter of reversing the disassembly process you performed earlier.

  1. Slide the hard drive carrier back into the case: Check the internal electrical wiring to make sure that no cables are pinched or in the way as you slide the case and carrier together.

  2. Snap the rear panel into place: Make sure the edges of the panel and the case line up and are a good fit. If the edges fail to line up, chances are a cable or wire in the case is pinched and preventing the case from closing completely.

  3. Screw the rear panel into place: Use the two small screws you set aside earlier to finish closing the case.

Connect Your DIY External Hard Drive

Once your drive has been fully assembled, connect your new external hard drive to your computer.

  1. Attach power to the enclosure: Most enclosures offer a power switch. Make sure the switch is set to off. Then, plug the included power cord or power adapter into the enclosure.

  2. Connect the data cable to the computer: Using the external interface of your choice, connect the appropriate data cable to the enclosure and then to the computer.

  3. Switch the enclosure’s power on: If the enclosure has a power-on light, it should be lit. After a few seconds, the computer should recognize that an external hard drive is connected.

Advice on Using Your External Hard Drive

Before unplugging the enclosure from your computer or turning off the enclosure's power, unmount or eject the drive first to make sure you safely disconnect the drive.

If you used a hard-disk drive as opposed to a solid-state drive, if you suddenly disconnect the drive after using it and walk away with it, the moving components inside can be damaged. This is part of why it's important to finish using the drive then safely disconnect it and power it down.

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