The IBM Model F is one of the most durable keyboards ever made. Even after 40+ years, a Model F can almost always be restored to feeling like new - with a bit of work.

I have restored many of these and learned many painful lessons along the way. In this post, I will take you along as I restore a Model F XT and share my process and tips.

You will need:

• Screwdriver

• Pliers

• Hammer/mallet (preferably rubber)

• Clamps

• Replacement foam (available pre-cut or you can make one yourself. More on this later)

• Keycap puller

Optional:

• Scrap piece of wood (for hammering on)

• Strip of rubber if you want to try to prevent scratching the bending tab on the plate

Step 1: Disassembly

Open the case to get at the keyboard assembly inside.

Remove the keycaps (keycap puller recommended).

WARNING: On an F XT/AT, the spacebar is NOT removable at this stage. Do not remove it yet or it will break. If there are square columns underneath the spacebar, it is NOT removable.

Square column underneath non-removable spacebar

Otherwise, the spacebar, as well as the other large stabilized keys, will have a wire that sits underneath plastic tabs on the barrel plate. Be careful taking these keys off. You really don't want to break the plastic tabs.

Once you have removed all the removable keycaps, it's time to open the assembly.

The barrel plate (top black metal plate) has several tabs that lock it into place on the back plate (shiny metal plate on the bottom).

All of these tabs have room to slide out except for one, which can only be bent away.

Right tab: a typical sliding tab. Left tab: the locking tab, which will need to be bent away.

First, bend out the locking tab so that it is no longer locking the two plates together. If you want to prevent any additional scratches, use a rubber sheet or similar between your pliers and the tab.

You may also find a flathead screwdriver useful if your pliers don't fit at first.

Locking tab successfully bent away

The next step will be to slide the back plate out. It may be held in place quite strongly; the hammer and scrap piece of wood will come in handy here.

Rest the barrel plate on the corner of the scrap wood:

Make sure it is the correct side; the back plate should have room to slide down at the sliding tabs.

Finally, carefully hammer the top edge of the back plate until it is free.

Note: When the assembly opens, all the innards will dump out. If you are careful, you can separate the assembly by hand after hammering it loose to prevent the innards getting everywhere.

You can now remove the flippers and barrels and put them aside for later.

If you have a non-removable spacebar, only now can you remove it. First remove the metal wire, then the keycap itself.

The metal wire has a slight bend in the middle; take note of which side it's on for reassembly!

Step 2: Cleaning

The flippers/springs usually only need a light dusting. Wipe the flippers if needed but avoid soaking the springs in water, as they can rust.

The PCB, backplate, and barrel plate usually only need to be wiped down.

Note: It is almost guaranteed that your barrel plate will have at least some rust. You can just ignore it, as it does not affect function. If you want, you can sand it down and repaint it. However, on any Model F other than the XT, this has an extra complication because of the wire stabilizer tabs that are melted into the barrel plate. If you paint over them, the stabilized keys may not feel right. If you remove them, it may be difficult to reattach them. If you try to tape them off, you may have poor results because they are so small.

The outer case of the keyboard is usually dirty and frustrating to clean. The problem is that the outer surface is almost always painted (that includes XT and AT, though it may not look like it), and paint is easy to damage.

I will not give specific instructions for cleaning the case as it depends a lot on what kind of gunk is on there, how clean you want it, etc. But I will give some important warnings.

WARNING: If you want to use anything more than a rag and warm soapy water, be very sure that you will not damage the surface of your case. It is easy to damage the surface of your case. For example:

• You may find that the green part of a sponge (or perhaps you found a so-called "magic eraser") is good at cleaning stuff. It is good at cleaning stuff because it is highly abrasive. It will very quickly scratch your keyboard.

• You may find that toothpaste is good at cleaning stuff. This is because toothpaste is abrasive. It will scratch your keyboard.

• You may find that baking soda is good at cleaning stuff. Once again, abrasive! (Not a whole lot, but it absolutely will scratch paint/plastic)

• You may find isopropanol useful for certain marks, like ink. Isopropanol is great at dissolving those. Isopropanol also dissolves paint (maybe not all? I don't know. But I know for a fact it will ruin at least some Model F case paint).

In my experience, anything that works significantly better than a rag and warm soapy water will damage the keyboard. I just stick to a rag and warm soapy water. With enough patience, it will clean just about any keyboard.

The warning above applies to the keycaps too.

My process for cleaning the keycaps/barrels: Put them in a jar with warm water and dish soap. Let it sit for a couple hours up to a couple days. Then simply rub the keycaps clean with a rag while they are still wet. For the barrels, use a pipe cleaner (and a toothbrush on the outside if you want to clean that too). Then rinse them with water.

Some foam types leave a horrible sticky residue on the barrels and barrel plate. Isopropanol is very useful for cleaning this, although it is not critical to clean it perfectly anyway because that residue will only make contact with the new foam you put in.

To dry the barrels/keycaps, simply lay them out on a towel for at least a couple days. The insides of the key stems are very good at holding water; do not assemble the keyboard until they are defintely dry.

Dissolved solids

When you rely on evaporation, the water will leave behind any solids that were dissolved in it. You may find this concerning for the key stems and barrels, as they will be sliding against eachother. For peace of mind, you can rinse them with distilled water (no dissolved solids). I don't know how much of a difference this makes, if it is at all perceptible. Maybe it would be noticeable if you have hard water. Distilled water is easy to come by anyway.

Step 3: Foam

In order to assemble the keyboard, the foam will very likely need to be replaced with a new one.

I will not go into much detail on how to cut a new one as there are several methods and frankly I haven't found one that isn't a huge pain. This is why I started producing them by machine. You can purchase those here.

If you choose to cut your own, this is the way I've done it in the past:

• Cut the foam into the desired rectangle shape.

• Lay it on the barrel plate (perhaps tape it to prevent it from moving around).

• Then trace every hole onto the foam with a pencil (if you are spray painting the barrel plate, you could use the spray paint to mark the holes).

• Then, with a hammer, the correctly sized punches, and a scrap piece of wood underneath, punch out each circular hole.

• Finally, cut out anything remaining with an exacto knife.

Step 4: Assembly

Finally, it's time to reassemble the keyboard. But don't celebrate yet, as this can be the most frustrating part of the whole process.

First, put the foam in the underside of the barrel plate and put the barrels in.

You will need to rest the barrel plate on two objects of equal height at the sides (here I used clamps):

If your keyboard has the non-removable spacebar, put the spacebar and the spacebar wire in now.

Next, put a flipper in each barrel that originally had one (on every Model F other than the XT, the larger (stabilized) keys have a second barrel underneath them that does not contain a flipper. If you have lost track of which those are, take a look at the corresponding keycap and check which barrel has the key stem (and flipper) and which is empty. These keys could be backspace, enter, left shift, right shift, spacebar, numpad enter, and/or numpad 0.

If your keyboard has the non-removable spacebar, take special note of that one. Even when you insert the flipper properly, it will not stay in position because there is a keycap in there already.

So, put it in last and hold it in place with your thumb. Then hold it with the back plate (with PCB and all).

Holding the flipper in using the back plate almost in position

Then slide the back plate into position, making sure it never lets the spacebar flipper out of place.

Now start putting clamps on the edges of the assembly.

If your keyboard has the plastic stabilizer tabs in the barrel plate, be careful not to crush them with the clamps!

If your keyboard has the non-removable spacebar, check now that it is properly clicking. If not, that probably means either the flipper is not properly seated or the wire is not properly inserted. It is much easier to reopen it and adjust it now than later!

How many clamps you need depends on how strong they clamp and which Model F you are working on (for example, F122 is notoriously hard to reassemble, requiring more clamps than the others. For F122, I use 8 of the pictured clamps plus an additional two extra large clamps in order to compress the inner tabs enough).

The bottom line is: the clamps must compress the assembly enough that each sliding tab will have enough room to get on top of the back plate when you start sliding in the back plate.

The foam here is sufficiently compressed. When the back plate slides to the right, it will hit the tapered part of the sliding tab and get pushed down to the correct level, where it will be able to slide all the way in.

Now hold the barrel plate on the corner of the scrap wood, just like for opening the assembly (except this time the other side of the keyboard).

Make sure it is correctly positioned so that the back plate has to slide down into position and start hammering away!

Be patient. You will need to hammer quite hard for it to slide in, but it will only work if it is sufficiently compressed. Double check and reposition the clamps as needed.

The back plate is fully in when it can't slide any farther:

Before removing the clamps, bend the locking tab in to prevent the back plate from sliding back out:

Finally, you can remove the clamps as you have successfully closed the keyboard assembly.

Next, put in the keycaps. This is much easier if you put the keycaps in while the keyboard is upside down, like so:

Once all the keycaps are in and correctly clicking, reassemble the rest of the keyboard and enjoy your restored Model F!