File and Rasp Distinctions
When choosing between a file and a rasp it’s important to consider the material you’re working with and how fine of a finish you need.
Files. Feature parallel, diagonal rows of teeth that form ridges across the surface. Each of the sides is either cut and has teeth or uncut and is smooth.
- Single-cut files have one set of teeth and are used to provide a somewhat smoother finish or create a sharp edge on knives, shears or saws. Use light pressure when working.
- Double-cut files feature a second set of teeth that cut in the opposite direction and are used for more aggressive filing, shaping or removing rust from metal and smoothing wood. Use heavier pressure when working.
- Curved-cut files feature curved contours across the face of the file and are used for a variety of automotive applications, such as smoothing body panels. They can also be used for working with plaster and fiberglass.
- Rasp-cut files feature a series of individual teeth and are used primarily on wood.
Rasps. Feature individual teeth that are randomly placed to provide a faster, rougher cut.
- Wood rasps have a very coarse surface and are used primarily for quick removal of stock.
- Cabinet rasps are best suited for finer, more delicate work and can be used on wood of all types, leather or soft materials.
- Patternmaker’s cabinet rasps provide a smoother finish.
- Horse rasps are used for working on horseshoes.
Files and rasps come in several different shapes. The chart below describes their unique set of advantages for different tasks.
Flat, Mill or Hand
- Features straight edges and a flat surface with a series of parallel teeth.
- Flat files taper in width and thickness from the middle outward
- Mill files taper in width and thickness all the way through
- Hand files taper only in thickness and feature a square point
- Features both a flat face and a curved face.
- Concave surfaces, edges and holes
- Flat face can be used for filing flat surfaces
- Curved face is ideal for use on grooves
- Circular design features teeth all the way around. Also called "rat-tail."
- Enlarging round openings
- Removing burrs from metal
- Features four cut sides.
- Enlarging rectangular openings
- Features two cut sides and one uncut side. Also called "taper" or "threesquare"
- Working on acute internal angles
- Squaring corners
- Filing grooves
- Sharpening saw teeth and other tools
File grades are often broken down into bastard cut, second cut or smooth cut.
- Bastard cut is the coarsest grade and is used to remove material quickly
- Second cut can also be used for fast removal but it provides a slightly smoother finish. Second cut is also known as medium cut.
- Smooth cut features a fine grade best used for finishing work and preparing surfaces for sanding.
Rasp grades include bastard, cabinet and wood.
- Unlike with files, a rasp bastard cut is the finest grade.
- Cabinet cut is also known as medium cut.
- Cabinet- and wood-grade rasps remove material quickly
Usage and Care
It’s important to choose the right combination of shape, size and grade for the project you’re working on. Also, proper care and technique is key to safe and effective use.
- When using tool push outwards across the surface and adjust pressure according to type of material you’re working with.
- Lift the tool at the end of the stroke and bring it back to the starting position before allowing it to touch the surface again.
- When files become clogged clean them with a wire brush or file card. Rubbing chalk on the surface of the tool can help prevent clogging.
- Always work in a well-ventilated area and use respiratory protection when necessary.
- Keep files in protective sleeves or slotted racks when not in use to prevent them from scraping against each other.
Handles. Ergonomic handles feature rubberized grips that provide greater comfort when using tools. Universal handles feature inserts that allow it to be used with different shapes.
4-in-1 Tool. A multi-faceted tool used for many different tasks. Some files are designed with both round and flat surfaces and others are a file and rasp in one tool.
File Card. Used to get in between the teeth of files and rasps to clean out sawdust, metal shavings and other debris.
Diamond File. Features ground diamond particles that make them well suited to industrial applications. Best used when working on fiberglass, epoxy and other hard surfaces. Smaller diamond files work well on glass, ceramic and various metals.