It works like this. Fix a 3 or 4 inch piece of square or rectangular brass into a file handle. File the end to a chisel shape. Put the file to be cleaned in the vice flat uppermost. Using the brass tool at a shallowish angle gouge out all the dross working side to side diagonally along the file parallel to the file teeth. The chisel point very quickly conforms to the pitch and shape of the file teeth and will get right down to the bottom of the serrations. Resharpen every so often as needed.
A handy length of flattened scrap central heating copper pipe works just as well as the brass bar and for the impecunious amongst us, could work out a cheaper option.
A handy length of flattened scrap central heating copper pipe works just as well as the brass bar and for the impecunious amongst us, could work out a cheaper option.
If you want a "file card", find a place that cards wool, or other fibre, thats what they use. My file card came from my Scotish grandfather Who lived in Paisely, so I presume it cme from one of the mills there.