I haven't made a folder yet, but I have made a template from mdf to see how everything fits up, moves and how or if the lock works.
I may be way off but that may be a easy starting place, if I'm wrong let me know.
I have read about the dye, thanks for the suggestion.
I etched a peice for a few minutes and it had a few darker lines runing through and wasn't sure if they were cracks.
I don't have enough experience to know one way or the other.
If a peice of steel has cracks ( that you cant otherwise see) , will they show up when you etch it?
http://www.vintagemachinery.org/pubs/detail.aspx?id=5105
Link to Wells Bros. & Co. catalog from 1895, has the little giant #4 on page 84 if you click the pdf.