Tools You'll Need to Build Your Own Computer
You don't need an expensive toolkit to build your own computer, but there are a few simple electronics tools that you absolutely must have. All of these can be easily obtained at almost any computer store or online.
You may already have some of these tools. If not, then the easiest way to get the tools you need is to purchase a computer repair tool kit that contains all the tools you'll need, as well as a handy carrying case to keep them organized.
As with all tools, you should buy the best quality computer tools that you can afford. Good tools last longer and make the job easier. All computer tools should be non-magnetized.
You will need, at a minimum, the following simple tools:
Screwdrivers and nut drivers. You should have, at a minimum, small- and medium-sized Phillips and flat screwdrivers and a 1/4" nut driver. A precision screwdriver set should have all the screwdrivers you'll need.
Cable Ties. Plastic cable ties are useful for neatly bundling wires and cables away from fans and other components inside the computer.
Anti-Static Kit. An anti-static kit consists of a rubberized mat and a wrist strap that attaches to both the mat and the computer or electronic device you're working on. This both protects the equipment from static damage and protects your tabletop from scratches. Click here for more information about anti-static precautions.
Heat Sink Compound. Heat sink compound improves the thermal efficiency of heat sinks and improves cooling. It's sometimes included with processor fans or heat sinks, but may also be purchased separately. It is applied neatly to the area where the processor contacts the heat sink to improve cooling efficiency. (Some heat sinks have the compound "built-in" behind a little peel-off label.) I like Arctic MX-4 or other silver-based thermal compounds.
Canned Air or Canless Air Duster. Canned air or a canless air duster air is used to blow dust out of the nooks and crannies of your computer. Never blow into a computer with your lips to remove dust. Your breath contains too much moisture (and maybe other things depending on what you ate for dinner). Also, never use a household vacuum cleaner nozzle to clean inside a computer. They generate way too much static.
Pill Bottle or a Small Container. You'll need a pill bottle or other small container to hold the various screws, jumpers, and other small parts used to assemble and configure a homebuilt computer.
Nice Computer Tools to Have, but Not Strictly Necessary
In addition to the above, if you plan on making computer-building an ongoing hobby or if you'd like to learn to repair computers, you may want to consider the following tools. They're not necessary for a typical computer-building project, but they're nice to have if you do this sort of work often or want to pursie the computer-repair trade.
Multimeter. All multimeters measure voltage and resistance, and many can do much more. In computer-related work, they're most often used to diagnose power problems, loose wires, switch problems, and ground faults.
Power Supply Tester. A power supply tester is a specialized tool that applies a load to all the output voltages of a power supply to check its proper functioning. It's a must-have for computer-repair technicians, and a "nice-to-have" for hobbyist computer builders.
Logic Probe. A logic probe is a tool used to check the operation and logical states of binary circuits. It's most often used for differential diagnosis of problems that could be due to various components (for example, is the RAM failing or is the chipset defective). It's an utterly useless tool unless you know enough about computer electronics to understand how to use it, and an indispensable one if you do.
Soldering Iron. A precision soldering iron is one of those tools that is rarely used in computer-repair work, but which has no substitute when you do need one. In computer-repair work, they're most often used to replace burnt-out capacitors on motherboards as a last-ditch effort to avoid having to replace the mobo.
Networking Tools. Every computer technician and network technician needs a networking tool kit to make or test network cables or troubleshoot network flaws. For hobbyists, it's more of a "cool-to-have" kind of thing.
Hard Drive Duplicator. A hard drive duplicator duplicates hard drives. Some things just make sense. They are available for both SATA and NVMe (M.2) drives. Most of them can also be used as docks to connect to the drive using USB (and sometimes eSATA). Computer technicians use hard drive duplicators all the time. Hobbyists probably don't need one unless they're really into the hobby.