I’m afraid I don’t know where to find diamond files in as fine a grit
as 1,000; I’m not sure if they’re made at all.
However, you can make your own. Take a piece of ordinary 1/4" copper
tubing which is as long as you want the finished file to be, beat the
tubing flat on an anvil all except for say two inches at one end which
will be the handle. Then on a bench block or other piece of flat steel
do some fine hammering to get it as even and as flat as you can, and
finally file out the hammering bumps. Now you have a strip of smooth
even copper with a round handle at one end. Or you can start with a
sawed strip of, say, 3/32" copper sheet.
Once the metal is smooth and flat just barely moisten one side with
olive oil. Then apply two or three dabs of 1,000 grit diamond powder,
each about the size of a pinhead. Spread the grit evenly over the
oiled copper with your finger. Then press it into the metal by rocking
a rounded polished piece of agate over it. The hardness difference is
such that the diamond particles will quickly embed themselves into the
While it’s not as robust as a sinter-embedded tool would be, the
resulting file works quite well, albeit you’ll need to use it with a
light touch and re-charge it with diamond from time to time.
I’ve used the same basic process with copper wire also, when I wanted
to cut rounded grooves into a curved bracelet stone. Just hold one end
of the wire in the vise, the other with the pliers, stretch, apply
olive opil and diamond grit, run the stone over it to embed the
diamond, and voila.
Hope that helps,