Few things in the computing world are as viscerally satisfying as typing on an old-school mechanical keyboard. That signature click-clack—probably louder than it should be in polite office society—generated by rapid-fire key presses with your flying fingers is something mostly lost to our touchscreens and our modern, ultra-slim, low-travel keyboards. But no one better understands that romantic pull, or works harder to preserve it, than Brandon Ermita.

Ermita runs Clicky Keyboards, a side job to his regular gig as Princeton University's IT manager. He finds, buys, rebuilds, and then sells IBM Model M keyboards to nostalgic, discerning geeks through his website. Mechanical (or clicky) keyboards improve typing speed and help eliminate carpal tunnel syndrome—but the real draw is the tactile feel of typing on a real keyboard; it's the reaction of feeling the physical switches under the keys. That "feeling" is exemplified by the Model M, and has helped create a surprisingly large market for a 30-year-old piece of equipment that weighs five pounds.

Cait Opperman for WIRED

Since 2004, Ermita has sold more than 4,000 rebuilt Model Ms to 62 countries at $80-$175 apiece. New stock sells out in days. It's like wine trading: There are slight differences to certain years and sub-models, and he can't be picky as to what will be his next stock. There are U.K-made models, rounded models, two-year-only models, models made of lightweight plastic. "Right now, I'm looking around, and I have around 150-200 keyboards in various states," he says. "I'm just surrounded by keyboards."

Though somewhat antiquated, these old keyboards still showcase some nice innovations. Typewriter keyboards feel the way they do because each key connects to a lever that, when pressed, acts on a type bar that presses ink to page. Computer keyboards have no lever and no type bar. Keystrokes register by way of electric signals sent from a contact beneath each key, which are sent to the computer through a wire. The means of activating that contact is mechanized. IBM patented the buckling spring key switch in 1978. It's a simple design: a key cap mounted on a spring mounted on a hammer. As you press the key, you feel progressively stronger resistance until the hammer snaps down on the electrical contact and the spring collapses. The force of the bent spring pushes the key cap (and your finger) back up.

Ermita began Clicky Keyboards to prepare for upcoming online academic database projects for Princeton. "Originally, the plan was simply to document the variety and publish online some of the rich history of the Model M keyboards," he says.

The Model M in 1985, and it was IBM's second swing at replicating the feel of typing on one of its electric typewriters. "They were built like tanks," says Ermita. Each Model M has over a pound of curved steel below the keys, and each mechanism has a life expectancy of 25 million presses per key. "You can still find working IBM electronic typewriters, and they're even older than these Model M's."

IBM was a major part of the evolution of the keyboard: Over the course of 14 years, the Model M transitioned people from typewriter to computer, and standardized the computer keyboard layout. And then IBM discontinued it. In 2005, just six years after human hands put together the last Model M, IBM left the personal computer business altogether.

For any 30-year-old keyboard, there are a thousand little pieces of failure.

"Unfortunately, now I'm seeing that these keyboards are 20 and 30 years old, and the supply is slowly dwindling," says Ermita. "For years and years I've said that this will be my last year, that I'm down to my last 100 keyboards, that I'm going to miss this wonderful time when it finally comes to an end, but as I keep on doing this and get more and more popularity, lots of other resellers or warehouse people contact me. They inquire whether I'm still interested because they hate throwing these things away, and they would much rather see them be useful as opposed to just being discarded."

Every mechanical switch design has its own feel. How hard you have to press, an actuation point that is a smooth bump or the sharp smacking of two colliding pieces or something else resonating through the key cap to your finger, and the subsequent release of tension that drives the key into the mounting plate all determine feel. Buckling springs are crisp and forceful; Apple's Japanese Alps switches of the Model M era wobble like little drunks; Topre's rubber-domed switches feel like typing on fresh clay; and Cherry's color-coded line ranges from softly linear Reds to sharply clacking, high-pitched Blues.

Major computer manufacturers no longer bundle mechanical keyboards with computers—it's cheaper to omit the switches. Membrane keyboards are just pressure pads with plastic keys laid over them, lacking the Model M's switch that sandwiches between them. When you press a key, you're only mushing that part of the pad down to make electrical contact. It feels like using a primitive touchscreen because that's exactly what it is.

Cait Opperman for WIRED

"For any 30-year-old keyboard, there are a thousand little pieces of failure," Ermita says. "Often times, the spring tension doesn't feel right, or there's a deep gouge in the plastic, or a previous person put a property tag on it. That said, I think of the hundred keyboards I regularly obtain in one batch, and perhaps as many as 80 or 85 percent of them can be fully restored. The remainder, they have other cosmetic or deep mechanical issues that it becomes a question, 'Do I just use it for spare parts, or do I want to invest 20 hours of work just to get it to work?'"

Four nuts hold the top panel to the keyboard. Ermita opens it up to yank 101 keys off their switches and lay open the machine's guts. The keys take turns in an ultrasonic jewelry cleaner, and he clears out three decades of crumbs, soda residue, dust, and hair jammed among the buckling springs.

"Compressed air just blows everything around," he says. "You want to capture and remove the debris carefully with a fine brush to remove the layers of dust." In extreme cases, he'll put on a surgical mask before vacuuming it out. "It can be gross."

The plastic welds holding the Model M's circuitry, contacts, and buckling springs together weaken and can break over decades of heavy use and abuse. "When I was a graduate student in neuroscience, I learned these very precise techniques in stereotactic surgery," Ermita says. "One of them is the availability of using these surgical drills similar to a Dremel, and the ability that you can make very, very precise holes and drills with specialized tools and use micro-screws and special adhesives." He cuts away the melted ends of broken and weak welds and uses small screws to remount the components in place. Once the keyboard is clean, repaired, and reassembled, he tests it using specialized software to ensure that every key functions with correct spring tension. It all takes 45 minutes to an hour.

Cait Opperman for WIRED

"Mechanical keyboards have become very popular, and I partly think that it's because of the desire for people to customize electronic tools as their own and to personalize the experience to their preference," says Ermita. "The choice of a keyboard as a personal tool is a very individual one. The keyboard is the device which allows one to convert internal thoughts and ideas into bits and bytes through one's hands."

"Computer manufacturers know how to play the number game and how to make a table focusing on the specs of the CPU cores, GPU speed, amount of RAM and screen DPI," he says. "The human factors of keyboard ergonomics is something that is hard to quantify and has historically been hard to advertise." While major manufacturers may have lost interest, as long as there are sympathetic resellers and recyclers sending him pallets of Model M's, Ermita can keep making them.

Clicky Keyboards is happy to ignore those who believe in "mass marketing" and "lowest common denominator" and "good enough," to instead just focus on providing quality product to those professionals and experts. As Ermita sees it, he's making a device for people who believe in IBM's own motto: "Good design is timeless."