I love the looks of a solid brass key and always wanted to build one, but never thought I could do it.
One day I discovered the "Radiotelegraphy" group (http://www.radiotelegraphy.net/).  On the site are some links of real craftsmen who love to make keys, and are happy to share their wealth of information.   One post from Ron, G3YUH, interested me particularly, since he explained in detail how to make one with basic tools.
Subsequently, I thought I could do that.  Of course, I did not want to make an exact copy but add some of my own ideas.
What works is to use new blades for the hacksaw and a new flat file with lots of patience.  In addition I used a drill press which I also used as a basic lathe to make the knob.  Some improvements are still on order, for example to add silver contacts but it turned out better than I thought and the action is much better than what I had in the past.
It has now a special place in my shack, and I am so happy about it that I like to share my excitement.