For some time I have been engraving Experimental Aircraft Data Plates. No matter how well I clamp down the thin aluminum sheet, there always seems to be an area that is slightly bowed above the work surface. When you are engraving to a depth of .003, there is not much room for error! Sometimes I have enough difference in the depth of cut to easily see, and I need to start over on a new piece.
I have considered a spring loaded tool holder for some time, but just could not see spending the money to buy one. All this has brought me to the point where I decided to build one from scratch. My design is similar to ones that I have seen, over the years, and provides me with a way to do PERFECT engraving every time.
I have put all the details on my web page. There is a Dimensioned Sectional drawing there so you can make your own if you wish, and I also have them available for sale, if you are interested.
Here is the link:
http://www.mrrace.com/SpringTool/George