Hi everybody! Welcome to my first instructable!
I apologize in advance if you find the pictures a bit poor.
I hope I make a good first impression... here goes:
After looking at some of the fancy retro keyboards at this site, I really wanted to make one myself.
Unfortunately, I lack the tools/space and money to get and cut brass, and I'm not confident enough to do so with any other metal.
Old typewriter keys, offered on eBay are quite expensive and usually only about 40 pieces per set.
I would need at least 2 if not more of these.
I also couldn't be sure if they were looking the same or at least similar.
I will use buttons!!!

Update 4/20/14: Due to all the questions, feedback and support for my instructable I felt compelled to improve it with some new photos and better writing. Thanks!

References and inspiration, thanks to all for to think outside the box:
Steampunk keyboard by phirzcol www.instructables.com/id/steampunk-keyboard/ (wood frame)
Miss Betsy's Steampunk Keyboard by MissBetsy www.instructables.com/id/Miss-Betsys-Steampunk-Keyboard/ (buttons, bic pen lights and roman numbers for function keys)
Most Detailed Steampunk Keyboard Instruction by Admiral Aaron Ravensdale www.instructables.com/id/Most-Detailed-Steampunk-Keyboard-Instruction/ (amazing job!!!)
Cheap and Easy to make Steampunk Keyboard by HighWing www.instructables.com/id/Cheap-and-Easy-to-make-Steampunk-Keyboard/
Steampunk Keyboard Mod By Jake von Slatt http://steampunkworkshop.com/keyboard.shtml
And obviously: /www.datamancer.net/keyboards/keyboards.htm

Materials:
1 keyboard
flat clothing buttons with metallic ring (about 110-120) 18 mm diameter
wood sheet (veneer, 1 mm thickness)
Bic pens or similar
transparent silicon sealant
Styrene sheet and "L" profiles like Evergreen (for rectangular keys)
three 5 mm color LED's (for numlock, capslock and scrolllock)
four 5 mm white or blue LED's+ matching resistors (for "bic pen lights")
on/off switch (for "bic pen lights")
four little wooden pennant tips (for "bic pen lights")
two medium drawers pulls (rear feets)
Cap nuts brass (decoration)
clear self-adhesive film (to protect the paper inserts for the keycaps)
Shoelaces (to cover the cable)

Step 1: Step 1: Select a Keyboard

Obviously if you are going to do this you will need a spare keyboard that you can take apart and cut up.
You can use any keyboard you have, even cordless, though when selecting one, try to keep some things in mind.
Select a keyboard that will allow you to wrap the wood in one axis.
More than one axis will complicate the process to an unbelievable level.
Not all keyboards make noise, and after modding, the noise might not sound the same.

The one I used here was an old APC f-21 keyboard (1991, twentythree years old!!!!).
Now it should be clear why it is called a semi-mechanical hybrid:
From mechanical keyboards it borrows the sliders, springs, and click plates, and omits the printed circuit board, individual contacts, and separate switch housings.
From membrane keyboards it borrows the membrane sheets.

I chose this one because I liked how the keys sounded when pressed.
They made a nice clicking noise that was almost like an old typewriter.
Which would be perfect for a steampunk mod.

Step 2: Step 2: Disassemble the Keyboard

Remove the top of the keyboard and all of the keys .
Do not damage the key stems as yo will be reusing them later.
Before we start this step, if you don't have a photographic memory, I might suggest that you take a picture or make a diagram of the keyboard before you start popping off keys.
This way you can reference it later when you need to put the keys back on.
Taking the keys off is very easy to do with a flat head screw driver.
Simply push the flat head screw driver all the way down between a key.
Then gently move the handle away from the key and it should pop right off.
Now find the key that you just popped off as it probably went flying!

Step 3: Step 3: Cover the Frame

Make a paper template, attach to the wood sheet and cut out the holes for the keys with a 12 mm punch.
Some will be square and some round.
Square holes will require a great deal of extra care for the wood will split.
The next step is to use cyanoacrylate to adhere the wood sheet to long edge of the keyboard.
Leave some overlap on the sides of the keyboard , you will be cutting them off later.
With a thin seam of quick dry glue adhere the wood to the plastic frame until the entire face is covered.
Once the top face is covered, also cover the sides of the plastic frame with wood.
Once the sides and top of the keyboard are covered with wood, use sandpaper that matches the hardness of the wood to finish the surface and take any blemishes out.
The finer the wood grain the finer the sandpaper you want to finish with.
Use a light poly spray to seal the wood .
Repeat over and over with the finest sandpaper available until satisfied.

Step 4: Step 4: Cut the Keys

This is by far the longest and most tedious part of this, and any Keyboard mod.
The Cutting of the keys!
Here we will need to modify the existing keys to look more like the keys on an old typewriter.
After removing the keys from the keyboard, I made a cut using wire cutters at each corner of each key.
Once these cuts were made, I used a pair of needle nose pliers to snap the apron off the keys.
A couple of bends on each apron was all it took to snap them off, leaving me with a key with only a top and a shaft, ready to receive the buttons.
Be carefully, every key have a distinctive angle and you can't insert the key anywhere later.

Step 5: Step 5: Key Letters

To make the letters for the new keys I had thought of designing them in Scribus.
If you don't have that, any other photo editing program should do.
I measured the inside of the buttons first (16,5 mm) and also measured the square keys because I wanted to keep them and not just replace them with round buttons.
So I drew the exact shape of the square buttons.
Then I printed and covered the paper sheet with clear self-adhesive film.
After punching all my letters and numbers out, I glued them to the inside of the buttons.
Maybe You should consider adding a coat of gloss or epoxy to protect them or clear nail polish.
I have tried and I do not like the result :-( , I prefer clear self-adhesive film.

Step 6: Step 6: Insert the Round Keys

Insert all the stems back in the keyboard.
Then, using epoxy glue, put the buttons on top of the stems.
I started in the middle and made sure to get the row as straight as possible!
I pried a few key-tops (buttons) back off and re-glued them because they were just misaligned.
A ruler helped with this job and I think, at the end, I did a pretty good job.

Step 7: Step 7: Rectangular Keys

What's left are the rectangular keys. You can replace them with round buttons but I do not like the result.
I prefer for this mod the original rectangular keys shape.
If the original has any means of keeping these keys from tilting and jamming, like in my case metal bars, try to preserve them. The new keys are made from Evergreen 1/16" styrene sheet and "L" profiles, available at your modelers hobby shop.
First I removed the edges of the original keys with heavy cutters or scissors.
Then I marked the exact size of the buttons on the styrene and cut it with scissors.
I found this "L" profile at the hobby shop and made the edge of the buttons. These look quite right with the round buttons.
I use a modeler's special styrene glue.
Slightly sand the corners to round them and on to the spray both to apply a couple layers of metal silver.
Finally cut the printout and glue the pieces in.

Step 8: Step 8: Test the Keys

With this, the basic keyboard is done.
At this point you might want to try every key if it works properly.
If it has a tendency to jam, remove the key gently from the keyboard and inspect the stem.
Maybe you marred it after all and there is a burr left; remove it with an X-Acto.
Or a piece of dirt is stuck to the stem.
Also check the hole.
Use a little bit of graphite dust, cross your fingers and put the key back in.

Step 9: Step 9: Keyboard Illumination

I stripped down Bic pens and insert two 5 mm blue leds perfectly with some help of hot glue.
I filled the empty pen with silicone sealant first.
The lateral posts are wooden pennant tips drilled horizontally and vertically.
I took the 5 volts for the circuit from the keyboard pcb and I installed the switch in the rear of the frame.
Also I change original 3 mm leds numlock, scrolllock and capslock indicators with 5 mm leds.

Step 10: Step 10: Old Keyboard 5-pin DIN to PS2

Look at this for step to step:
https://www.instructables.com/id/Old-Keyboard-5-pin-DIN-to-PS2-converter/

Step 11: Step 11: Cloth Covered Cable

After a lot of hard work, I realized that also the keyboard cable needed to be "steampunked" !!!
Looking for alternatives I found two interesting instructables:
Cloth Covered Banana Cables by Aud1073cH www.instructables.com/id/Cloth-Covered-Banana-Cables/
Steampunk USB Cable by Winged Fist www.instructables.com/id/Steampunk-USB-cable/

I found a brown shoelace with a size compatible with my cable and then I passed the cable through the lace.
It’s a simple but tedious process...

And...That's all folks...

Thanks in advance for your comments!!!