Last Updated on June 13, 2022 by Dave Farquhar
Many modern computers don’t require any tools to work on. But that’s not always the case, especially with vintage computers, or less-expensive DIY cases. A nut driver, also known as a hex driver or hex nut driver, makes things easier. So what is the right size nut driver for computers? Or do you need more than one?
The most useful size nut driver for computers: 1/4″
A quarter-inch nut driver is the most useful size for working on PCs. The screws used to hold in motherboards and hold the case together generally have a quarter-inch hex head on them. So using a quarter-inch hex driver is a convenient way to tighten and loosen them without the risk of stripping the head. If it’s too late for that and you’ve already stripped the head, the hex sides provide an alternative way to remove the screw.
I’ve generally found the hex driver to be faster than a Phillips driver. I’ve always preferred to use a quarter-inch hex driver, when I can find mine. Keeping an at least semi-organized tool box helps with that, not that I’m as disciplined about that as I could be.
Conveniently, the most common size for interchangeable screw bits is 1/4-inch. So most screwdrivers that use changeable bits have a quarter-inch hex head.
Use a 5mm nut driver for port and motherboard standoffs
We don’t have to deal with port screws as often anymore thanks to modern connectors like HDMI, Displayport, DVI, and USB. But VGA ports and old-school serial and parallel ports all have hex standoffs next to them that your cables can screw into to secure them. And of course, sometimes that connection seizes, and when you go to remove the cable, you remove the standoff with it. It happened to the VGA port on my Compaq 486. And I know for a fact I’m not the only one this has happened to, because the Apple IIe I bought last summer had loose ports on them, due to the standoffs coming loose.
Most computer ports use a 5mm hex head. That means a 5mm hex driver is the correct tool for tightening or replacing them.
The standoffs that motherboards bolt into aren’t all that well standardized, but I find they are usually either 5mm or 3/16 inch. A 5mm driver will fit a 3/16 hex head well enough to work if you don’t have a 3/16 bit.
A 5mm driver is harder to find than it needs to be. Harbor Freight’s 16-piece precision screwdriver set includes one. It’s inexpensive, and usually eligible for coupons, which makes it even less expensive if you know my secrets for timing Harbor Freight sales.
What size screwdrivers for computers?
Sometimes you can’t get around the need for screwdrivers as well. The correct size Phillips driver for almost every common computer case screw is a #2 Phillips. Using a #2 Phillips greatly reduces the chances of stripping the head.
Compaq was very fond of T15 Torx bits. HP inherited this when they bought Compaq, and sometimes Dell uses T15 bits as well. Torx heads are much less common, but also much less likely to strip if someone overtightens them or they seize up.
Preventing standoffs from coming out and screws seizing
To keep a standoff from coming out accidentally, loosen it enough to expose most of the threads. You don’t have to completely remove it. Then apply a drop of Loctite threadlocker to the threads, retighten it, and let it sit for at least 10 minutes. The blue threadlocker, marketed as formulation #242, is removable if you ever need to remove it. It just puts up a good fight–more fight than a seized screw can generally give.
For good measure, dab a bit of anti seize lubricant, available at auto parts stores, onto the threads of the standoff. A toothpick works well for this. It doesn’t take much, and an application lasts decades.
By using threadlocker on standoffs that you don’t want to remove and don’t expect to remove often at all, and anti-seize where you do, you can pretty much eliminate the difficulty of removing screws and damaging heads.
David Farquhar is a computer security professional, entrepreneur, and author. He started his career as a part-time computer technician in 1994, worked his way up to system administrator by 1997, and has specialized in vulnerability management since 2013. He invests in real estate on the side and his hobbies include O gauge trains, baseball cards, and retro computers and video games. A University of Missouri graduate, he holds CISSP and Security+ certifications. He lives in St. Louis with his family.