IBM Buckling Spring Keyboard

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The IBM Buckling Spring keyboards are widely regarded as the best keyboards ever built. They were designed to emulate the feel and sounds of an IBM Selectric typewriter, and were bundled with every IBM PC (AT, XT, PS/2) as well as IBM Terminals. The IBM Model M keyboard is a classic piece of computing history, included with the many popular models of the IBM PC, whose signature loud clacking sound still lingers on as the sign of a true keyboard, a true descendant of the IBM Selectric typewriters.

What makes the Model M special and sought after by collectors to this day is it's durability, it's ease of repair, and the feel of it's buckling spring keyswitches; everything which has been lost in modern keyboards. And what other vintage computing technology can you think of that is still usable 30 years later?

However, the Model M's PS/2 keyboard socket is an aging format, long since superseded by the all-purpose USB port. You need an active PS/2 converter to USB, a passive one will not work. The Model Ms are getting rarer and more expensive with every passing year. And that's if your keyboard is lucky enough to have a PS/2 socket:

Buying a Model M[edit]

In the modern day, you have two ways of buying a Model M keyboard; buy a new one from Unicomp, or look for an old one on eBay.

In 2003, a used Model M could be found in working order at the junkyard for just a few dollars. But those days are gone, so we're left to eBay auctions by people who generally know the value of their product. Expect to pay around $30-$150 for used models, depending on the state of disrepair.

Make sure that you avoid any keyboard with an RJ-45 "telephone" plug; these are obsolete terminal connections, and cannot be converted to PS/2 and USB without difficult hardware modification. However, they are inexpensive ($15-30), making them a great source of genuine replacement keycaps on the cheap.

Variants and differences[edit]

All Model M keyboards have the same keyswitch design with negligible differences in feel. However, there were many variants over the years, and three main manufacturers.

(Create icons that show features, like that on the Thinkwiki.) PS/2, USB, removable SDL cable, water channels, doubleshot keycaps,

  • IBM (1985-1992) - The Model M was a lighter, PC-bound version of the Model F terminal keyboard, bundled with the first IBM PC. The only interesting feature is that these used AT cables (which are electrically compatible with PS/2, and can then be converted to USB). Since the original IBM PCs were expensive, serious business products, these are not as common.
  • Lexmark (1992-1998) - IBM divested it's typewriter and printing divisions into Lexmark, and had the Model M keyboards built on contract. These are the most common variant. No change in keyswitch technology, though water drainage channels were added. However, the cable is no longer replaceable.
  • Unicomp (1999-Modern Day) - A few Lexmark employees took the patents and the machinery of the Model M with them to form Unicomp, which still cranks out the good ol' keyboard in an American factory. They sell the only buckling spring keyboard that can be bought new, including a USB cable, a more compact case, and the sometimes reviled Windows key. The keyswitches are still the same, but the keys are no longer doubleshot, the key labels are adhered, and the key stem is all in one piece (like the Shift key on the IBM Model M). Also, Unicomp uses the same old injection molding machines from 30 years ago. They're starting to wear out, and the result is minor, hard to see cosmetic overshots on the keys.

Required Parts[edit]

  • PS/2 to USB Interpreter - Not your ordinary adapter. This one has a chipset that actually converts the signal and gives the keyboard enough power, which the cheap adapters don't do.

Cleaning Tools[edit]

  • 7/32" Nut Driver - This is a very special size, not the kind you'll find in a hardware store, so you'll generally have to buy it online.
  • 2 Double Medium Ziploc bags
  • Disposable, circular paintbrush - Depending on what's in your board, you might not want to reuse your brush...
  • Sponge Brush - For soaking up the water and gunk.
  • Liquid Soap and Water
  • Hair dryer, or the hot sun - To quickly dry off your keys.
  • Old, unneeded microfiber cloth (optional)

Cleaning the Model M[edit]

The IBM Model M is built to last, and made for easy maintenance. The key levels are burned in and won't rub off, and the whole thing is made of plastic that will never discolor (though removable gunk might obscure the original color on the surface).


(Be careful when removing the Caps Lock key, some people have had problems removing it.)

  1. Remove the keycaps by pulling the key up from the sides. Place them in a ziploc bag. Some keys aren't doubleshot (i.e. the shift, enter, spacebar), so sort those with the keystems.
  2. Remove the keystems by firmly pulling up, and place them in a ziploc bag.
  3. From the top of the back of the keyboard, open up the case using the nut driver.
    • Be very careful not to damage the rivets on the back of the steel plate! These are delicate, unlike the rest of the keyboard, yet are vital to keeping the keys stable.

Washing the Keycaps[edit]

  1. Pick up the bags where the keycaps are stored.
  2. Dump water and pump plenty of soap into the bags. Shake well.
  3. Dry the keycaps out with a hair dryer, or in the hot sun for a couple hours. (Picture)

Washing the Keystems[edit]

Since the keystems are more difficult to clean and dry, only wash the keystems if they smell strange, or are actually dirty.

  1. Pick up the bags where the keystems are stored.
  2. Dump water and pump plenty of soap into the bags. Shake well.
  3. To minimize rust, we can't allow water to reach the springs. Shake out embedded water individually for every single keystem, to make drying easier.
  4. Throughly dry each keystem out with a hair dryer, or in the hot sun, with all stems facing up.

Washing the Case[edit]

  1. Wash off the front side of the case by hand, with dishwasher soap.
  2. If the paper label is still on the keyboard, protect it with a rigid piece of plastic surrounded by duct tape.
  3. Now you can wash the back side of the case without worry. However, if water still leaks into the label, finish washing, remove the tape, and dry the label off immediately with a towel and hair dryer.

Cleaning the keybase[edit]

  1. Get a disposable paintbrush, dip it in soap, and use it to push off all the gunk on the keybase. Be careful not to let too much water get on the springs.
  2. Use the sponge brush to wipe away the water and sweep away remaining gunk.


You might want to keep an image of a Model M keyboard handy while reinserting the keycaps.

  1. After all components are fully dried and cleaned, insert them back into the keybase.
  2. When inserting keystems, try to keep springs in the middle while inserting, and test them for that signature click.
  3. Don't worry, you can remove the stems if there are issues; it's just going to be harder when everything is back in place. (Picture)

Now enjoy your fresh and clean keyboard.