One of the methods mentioned for making a tapered wire involves using
a file and a grooved block. A drawback to this method is the time and
effort that it takes. One way to speed up the process is to use an
appropriately sized and graded tool.
For example, while a small wire, say 18 gauge, can be effectively
tapered with needle files, to file a six inch taper on a length of 10
gauge wire would take a long time. However, by using a big and coarse
file, like a 10 inch mill file, the work will go much faster.
You don’t always need costly precision files to do fine work. Big
files like the mill file mentioned can be purchased at Home Depot or
Amazon for little money.
Here’s a source for about files, their applications and
how to use them, from Nicholson, a U. S. producer of high quality