A file is a metalworking tool used to remove unwanted burrs or blemishes on metal surfaces and edges. Also used to enlarge holes or create channels.
Using a Jeweller’s File
Files are made of tempered steel and have forward-facing cutting teeth.
It is a good idea to have specific files for working with different metals as remnants of steel and lead can taint precious metals when they are annealed or pickled.
To clean, tap the file against a wooden surface to dislodge any loose debris or use a brass brush to clear the teeth of lemel.
File Types, Cuts and Numbering
A single-cut file has one set of parallel teeth while a cross-cut or double-cut file has a second set of cuts forming diamond shaped cutting surfaces.
In Swiss-pattern files the teeth are cut at a shallower angle, and are graded by number. Swiss Pattern files are available in seven cuts, ranging in coarseness from ØØ to No. 6, with No. 6 being the finest cut. Made to exacting measurements, these files are smaller and finer than American Pattern files.
Swiss Pattern files are usually between 75mm and 150mm long, and are available in a wide range of fine cuts. With teeth that extend to the edge and narrow points for working in tight areas, Swiss Pattern files are ideal for detailed work, often used by jewellers, watchmakers, model makers, and tool and die makers. etc.
American Pattern files are available in three grades of cut: Bastard, Second Cut and Smooth. The length of a file also affects the coarseness, regardless of the cut. For example a 6″ Bastard Cut is a lot finer than a 12″ Bastard Cut. This is because shorter files are generally used for finer work. Overall, the finest would be a 4″ Smooth file and the coarsest would be a 16″ Bastard file. The relationship between the grades of coarseness for each length remains the same.