MOLDED KEY TOPS

[BSimon999@AOL.COM]

In a message dated 12/16/99 7:08:40 PM, tomnjan@bellsouth.net writes:

<< On trimming one of the newly installed key tops by
hand using a rasp made of a carefully squared plank and attached
sandpaper, I discovered that the key wood was not square, thus the key
and top now displays a noticeable taper.>>

For best work, Jigs and sandpaper just don't do a good job because they sand 
the side of the key as well as the top. If you were only to lightly touch the 
side of the key with sandpaper and "just clean them up to fresh wood", taking 
off only the thickness of a postage stamp, that would be .005" to .006" off 
of each side, seemingly trivial.  But -  times two sides of the key, -equals 
perhaps .012" per key  - times 52 keys - equals  five-eighths of an inch of 
gap width added to the set of keys. 

This is the minimum! The operations I have seen doing keys badly  just run 
the side of the key against a moving belt or disk, and since they sand, then 
look, then sand, then look, they cannot see as they sand and they frequently 
take .015" or .020" inches off each side. ( times two sides equals .040", 
times 52 keys equals TWO INCHES of gap added to whatever the keys already 
had. The keys look like  stand alone teeth in the mouth of an old man with 
receding gums.

Don't sand, EVER, - because you always sand off wood and increase gap.

The keys I do look fantastic, and I take nothing off the wood sides of the 
keys. I  trim off only  the top material.  I use a very fine 10 inch single 
mill file. 

Buy a new file of top quality, never use it on anything but plastic key tops 
and it will stay very sharp and cut very fast  forever. Pad the jaws of a 
good 4" vise with thick leather and lightly clamp the key side to be trimmed 
facing up. ( Generally more stable if you actually clamp on the key top 
itself, just leaving 1/4"  stick above the jaws of the vise. ) Using a handle 
on the tang,  fore and aft grip on the file and light pressure, just file 
down the plastic. You can see the amount of material removed with every 
stroke. You can see, and feel, that you have only perhaps .001" to .002" left 
before the side of the key top is dead flat with the wood of the key, and one 
last light lick with the file placed flat on the wood takes the key top dead 
even with the side, and only removes the dirty fingerprints from the side of 
the key, - and no wood at all.  You can easily feel the file going from a 
cutting action to a sliding condition. It is a "skill" thing.

Then put the key upright in the vise, clamped farther back  with the entire 
key top sticking well out and lightly radius the edges and corners of the top 
with the same file.  Polish. Done.

This actually goes fairly fast, and the result is superb.

This method DOES NOT WORK with a poor quality or dull file. You will stand 
there cursing because it is taking waaaaay too long.

One possible variant to this method is to use a medium mill file to take the 
excess key top material off to about .006" to .010" remaining, then switch to 
a fine file to finish.

Happy Holidays,

Bill Simon
Phoenix