Metal Files: Your Complete Selection Guide
From heavy stock removal to fine finishing, learn which file type, tooth pattern, and coarseness will deliver the results you need.
Hand file selection depends on the size and contours of the item you are shaping, as well as personal preference and the specific task. To get the best results, start by considering the work to be done, then choose the appropriate file size, coarseness, tooth type, and shape.
The metal file size and coarseness go hand in hand. Larger files are coarser, removing more material but leaving a rougher finish. Smaller files are finer, removing less material but producing a smoother finish.
Once you determine the size and coarseness, select the tooth type. Use double-cut files for fast stock removal, and smooth double-cut or single-cut files for finishing work.
File shape plays a major role in achieving the desired contour. A triangular file works best for acute internal angles, square corners, and sharpening saw teeth. Flat files are for general-purpose work, square files for enlarging rectangular holes, round files for enlarging round holes, and half-round files for both flat surfaces and curved grooves.
Parts of a Hand File & Terminology
Back: The convex side of a half-round or similarly shaped file.
Edge/Safe Edge: The side surfaces of a file. May be smooth (safe edge) or have teeth.
Handle: A holder into which the tang of the file fits. If the file has an integral holder, this is known as a solid handle file.
Pinning: The buildup of filings lodged between the file’s teeth.
Shelling: The breakage of file teeth, often caused by excessive pressure, reverse filing, or filing sharp corners and edges.
Understanding Hand File Tooth Types and Coarseness
Two key attributes determine how aggressively a metal file removes material and how smooth the resulting finish will be: tooth type and coarseness. Choosing the right combination depends on whether the task is roughing (removing material quickly) or finishing (creating a smooth, refined surface).
Metal File Teeth Types
Metal File Coarseness
Metal File Shapes
The type or shape of a file refers to its cross-section, such as rectangular, square, round, half-round, or triangular. The shape should match the area being filed. File types are further classified by their contour: blunt or tapered.
Blunt File
Maintains a constant width with parallel edges from end to end. Ideal for uniform workpieces where only one file size is needed.
Taper File
Decreases in width, thickness, or both from heel to point. Allows the user to vary the contact area without changing files, making it useful for complex shapes and varying filing needs.
How to Use a File Correctly
Metal File Care
- Protect the teeth of the file when not in use by hanging it on a rack or keeping it in a drawer with wooden divisions.
- Keep hand files clear of water or grease, as these can impair their cutting action.
- When carrying hand files in a toolbox, wrap them in a cloth for protection.
- Keep file teeth clean at all times by using a file card or a wire file brush to clear the grooves between the teeth.
- Never use a metal file without a tight-fitting handle, as serious accidents can result if the handle becomes detached, exposing the sharp point of the tongue.