Types of Files Used in ITI Fitter Shop: Easy 2026 Selection Guide

1. Construction & Structural Anatomy of Types of Files Used in Fitter Shop

In workshop engineering practice, a hand file is a multi-point hardened steel cutting tool designed to remove microscopic metal chips from workpieces. Trainees learning about the types of files used in fitter shop operations must understand that files are manufactured from high-carbon steel (HCS) or high-grade alloy steel, with the main body hardened while the tang remains soft to absorb operational shock.

Selecting the appropriate types of files used in fitter shop environments helps apprentices maintain flat reference surfaces without rocking the workpiece during bench fitting.

1.1 Anatomy of Workshop Hand Files

• Tang: The tapered, unhardened rear end fitted into the wooden or plastic handle.
• Heel: The smooth portion of the file body adjacent to the shoulder where no teeth are cut.
• Face: The broad, flat surface containing rows of cutting teeth.
• Edge: The narrow side of the file, which may feature single-cut teeth or a safe edge.
• Point / Tip: The front end opposite the tang.
• Safe Edge: An un-toothed edge designed to protect adjacent internal shoulders while filing 90-degree corners.

For trainees studying trade theory, additional precision measurement guides are available in our tutorial on Vernier Caliper and Micrometer Least Count Calculations or within the main Trade Theory Category Hub. Official syllabus outlines can be reviewed on the Bharat Skills Official Portal.

2. Classification by Cut: Single Cut vs Double Cut Files

When categorizing the types of files used in fitter shop tasks, the pattern and angle of cutting teeth determine how metal chips are sheared from the workpiece surface. Understanding the single cut vs double cut file difference is critical when choosing between soft non-ferrous metals and hard alloy steel workpieces.

2.1 Single Cut Files

Among the primary types of files used in fitter shop practice, single-cut files feature parallel rows of teeth running diagonally across the face at an angle of 60 degrees to the center line. They produce a smooth surface finish and are primarily used for filing soft metals like aluminum, brass, copper, and tin, as well as during draw filing operations.

2.2 Double Cut Files

Double-cut files possess two intersecting sets of teeth. The first set, known as the Over-cut, is cut at an angle of 70 degrees, while the second set, called the Up-cut, is cut at an angle of 51 degrees to the center line. These double-cut types of files used in fitter shop jobs break chips into smaller fragments for rapid stock removal on hard steel parts.

2.3 Rasp Cut & Curved Cut Files

• Rasp Cut: Features individual, raised triangular teeth. It is used exclusively for filing soft non-metallic materials such as wood, leather, and plastic.
• Curved Cut (Vixen File): Features continuous curved teeth designed for finishing soft sheet metal panels, such as aluminum automobile bodies.

3. Classification by Grade: Rough, Bastard, Second Cut & Smooth Files

The grade of a file refers to the spacing and pitch of its teeth per linear centimeter. Selecting among the different grade types of files used in fitter shop practice depends on the amount of material stock to be removed and the required surface roughness value.

4. Classification by Cross-Sectional Shape & Industrial Applications

Various shape profiles represent specialized types of files used in fitter shop assemblies to accommodate complex geometries such as keyways, internal splines, square slots, and V-grooves.

4.1 Flat File vs Hand File

Comparing shape profile types of files used in fitter shop work is a frequent requirement in NCVT trade examinations:

• Flat File: Rectangular in cross-section, tapered in width and thickness for the front one-third of its length. Double cut on faces and single cut on edges.
• Hand File (Safe Edge File): Parallel in width throughout its entire length, tapered only in thickness. One edge is un-toothed (safe edge) to allow filing up to internal 90-degree steps without damaging adjacent sides.

4.2 Other Essential File Shapes

• Square File: Square cross-section, tapered toward the point. Used for filing keyways, square holes, and rectangular slots.
• Three-Square (Triangular) File: Equilateral triangular cross-section with 60-degree internal angles. Used for filing internal corners and sharpening saw teeth.
• Half-Round File: Curved back with a flat face. The curved side is used for shaping concave surfaces and internal radii.
• Round File (Rat Tail): Circular cross-section, tapered toward the point. Used for enlarging cylindrical holes and finishing fillet radii.
• Needle Files: Precision miniature files supplied in sets of 12 for delicate die-making, instrument repair, and jeweler work.

5. Pinning of File & Workshop Maintenance Protocols

While operating various types of files used in fitter shop environments, particularly on soft metals like aluminum or brass, small particles of metal become trapped between the file teeth. This defect is known as pinning of the file.

5.1 Consequences & Removal of Pinning

Pinned file teeth scratch the workpiece surface, leading to deep gouges. Knowing how to maintain all types of files used in fitter shop toolkits ensures consistent fitting quality:

• File Card Usage: Clean clogged file teeth using a standard wire file card, brushing parallel to the row of teeth (along the overcut angle).
• Copper Strip Cleaning: For stubbornly embedded metal particles, push a thin copper strip across the tooth gullets to dislodge trapped chips.
• Chalk Application: Apply a light coat of powdered chalk over the file teeth before filing soft metals to reduce chip adhesion.

5.2 Essential Care Guidelines

• Never use any types of files used in fitter shop tasks without a securely fitted wooden or plastic handle to prevent injury from the sharp tang.
• Store files separately in tool racks or canvas rolls. Do not stack them together, as hard teeth contact causes chipping.
• Never hammer on a file or use it as a pry bar; hardened tool steel is brittle and can shatter.
• For dimensional verification guidelines, consult our guide to Limit Fit and Tolerance Standards or check directives on the MSDE Official Portal.

6. NIMI Pattern Mock Tests & Category Navigation

Master all technical questions on types of files used in fitter shop modules for your upcoming NCVT AITT online Computer-Based Tests (CBT) across our main study categories:

7. Frequently Asked Questions (NCVT CBT Exam Focus)

Q1: What are the main types of files used in a fitter shop for rough metal removal?
Ans: Rough files and Bastard files are the primary types used for rapid stock reduction before final sizing.

Q2: What is the tooth angle of a single-cut file?
Ans: In a single-cut file, the teeth are cut at an angle of 60 degrees to the center line.

Q3: Why is a safe edge provided on a hand file?
Ans: A safe edge has no teeth, allowing filing up to internal 90-degree corners without damaging the adjacent finished shoulder.

Q4: How do you clean metal particles trapped during pinning of a file?
Ans: Clean clogged teeth using a wire file card brushed parallel to the over-cut teeth or by pushing a soft brass/copper strip along the tooth gullets.