Files & Rasps

By: John Kelsey, This Old House magazine (Page 1 of 6)

Photo: John Kelsey

Photo: John Kelsey

Photo: John Kelsey

HALF-ROUND
For concave surfaces and edges, holes

Photo: John Kelsey

ROUND OR RAT-TAIL
For round holes

Photo: John Kelsey

FLAT, MILL, AND HAND
For flat surfaces, straight edges. Traditionally, a flat file tapers in width and thickness from the middle of the belly, a mill file tapers in width and thickness throughout, and a hand file tapers only in thickness — the point is square (called a blunt).

Photo: John Kelsey

TAPER (a.k.a. THREESQUARE OR TRIANGULAR)
For handsaw teeth, squared holes.

Photo: John Kelsey

CHAIN SAW
For chain-saw teeth

Photo: John Kelsey

SINGLE-CUT
Teeth arranged in parallel grooves. Best for sharpening, deburring, or smoothing metal and plastic.

Photo: John Kelsey

DOUBLE-CUT
Crisscrossed teeth. Best for shaping or derusting metal and smoothing wood

Photo: John Kelsey

CURVED
Teeth arranged in parallel arcs. Best for shaping and smoothing decorative plaster, fiberglass, and auto-body putty

Photo: John Kelsey

RASP
Coarse, pyramidlike teeth. Best for shaping wood

Photo: John Kelsey

Nicholson ergonomic file handle with inserts, from Cooper Tools, $4

Photo: John Kelsey

If You Need To:
Smooth wood or work thick metal, as when removing heavy rust from a lawn mower blade or sharpening a shovel.

Choose a:
MILL BASTARD

Shown here:
Craftsman 10-inch mill file, from Sears, $8

Photo: John Kelsey

If You Need To:
Sharpen a fine blade, as on an axe or lawn mower; flatten wood or metal.

Choose a:
FLAT DOUBLE-CUT

Shown here:
Craftsman 10-inch flat Multi-Kut file, from Sears, $6

8-inch All-Purpose Black Maxi file, from Simonds International

Photo: John Kelsey

If You Need To:
Deburr plastic or metal, remove the scratches from a flattened surface, file a metal part to a precise fit.

Choose a:
FLAT or HAND SINGLE-CUT

Shown here:
8-inch All-Purpose Black Maxi, from Simonds International, $8.50

10-inch Pattern Maker cabinet rasp, from Cooper Tools

Photo: John Kelsey

If You Need To:
Rapidly rough out a wooden handle or part.

Choose a:
HALF-ROUND CABINENT'S RASP

Shown here:
Nicholson 10-inch Pattern Maker cabinet rasp, from Cooper Tools, $40

Snap-on triangular slim taper miniature file

Photo: John Kelsey

If You Need To:
Sharpen a tool with teeth or crevices, such as a handsaw or steel (not carbide) drill bit.

Choose a:
SMALL SLIM TAPER

Shown here:
Snap-on triangular slim taper miniature file, $5.50

Nicholson round bastard, from Cooper Tools

Photo: John Kelsey

If You Need To:
Enlarge a wood hole, deburr the inside of a pipe.

Choose a:
RAT-TAIL

Shown here:
Nicholson round bastard, from Cooper Tools, $6

Collar 8-inch shoe rasp/four-in-hand, from AngloAmerican Tools

Photo: John Kelsey

If You Need To:
Outfit a tool kit with a general-purpose file that has both file and rasp teeth and curved and flat sides.

Choose a:
FOUR-IN-HAND FILE (SHOE RASP)

Shown here:
Collar 8-inch shoe rasp/four-in-hand, from AngloAmerican Tools, $7.50

Nicholson 10-inch file card and brush, from Cooper Tools

Photo: John Kelsey

If You Need To:
Clean sawdust and metal shavings out of file teeth.

Choose a:
FILE CARD

Shown here:
Nicholson 10-inch file card and brush, from Cooper Tools, $16

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What You'll Learn:

When you want to break out of jail, have someone bake you a cake with a hacksaw in it. But if you'd rather make a key from a spoon and quietly slip away like Houdini, ask for a cake with a 6-inch slim taper file.

Files shape, trim, and smooth anything made of metal, wood, or plastic. With their closely spaced, hardened steel grooves, they can sharpen a lawn-mower blade, knock the rust off a shovel, and remove burrs from a product with "some assembly required." Rasps are files made specifically for wood. Their coarse, individual teeth, punched up from the steel surface, are perfect for grating away at lumber. Both files and rasps are meant to be used between the rough cut of a saw and the smoothing of sandpaper — not instead of either one.

Because of all the possible combinations of teeth patterns, coarseness, shape, and thickness, there are countless kinds of files and rasps made for every common material and need. On the following pages, you'll learn how to tell a four-in-hand from a rat-tail, and find a selection of types that will help you through most jobs on the homestead.