Metal file cabinets are a staple in many offices and organizations, providing secure and organized document storage. But what exactly are these ubiquitous office furniture pieces made out of? The materials used to construct metal file cabinets can vary, but they typically include steel, aluminum, and sometimes even wood.

Steel – The Primary Building Material

The majority of metal file cabinets are made primarily of steel. Steel is a strong, durable metal alloy composed mainly of iron with additions of carbon and other metals. It offers an optimal balance of strength, durability, and affordability, making it well-suited for fabricating file cabinets.

There are a few main reasons why steel is commonly used:

Strength and Durability

Steel is simply stronger than other metals like aluminum. It has a very high tensile strength, meaning it resists breakage under pressure. This is vital for file cabinets which need to stand up to daily use and abuse. The strength of steel also allows metal file cabinets to be thinner yet still sturdy.

Steel’s inherent strength lends well to making durable file cabinet constructions that can withstand bumps and bangs and avoid becoming misaligned or warped. Quality steel file cabinets can easily last for decades with proper care.

Fire Resistance

Properly manufactured steel is naturally fire-resistant, an important feature in office furniture. Steel file cabinet frames will maintain their integrity better than other materials if exposed to high heat. Some metal file cabinets are even rated for 1-2 hour fire protection of documents inside.

Cost Efficiency

Steel is more affordable than other cabinet-building metals like stainless steel or aluminum. This allows steel file cabinets to be mass produced at costs reasonable for most businesses and organizations. The relatively low cost makes replacing old worn-out steel file cabinets more practical as well.

Customizability

Steel is easy to shape, cut, and weld. This facilitates the production of metal file cabinets in a wide variety of sizes and configurations to suit specific needs. Custom paint colors and finishes can also be applied to steel for aesthetics.

Aluminum and Stainless Steel Options

While the majority of metal file cabinets rely on steel construction, some higher-end models incorporate aluminum or stainless steel:

Aluminum File Cabinets

Aluminum provides an ultra-lightweight alternative to steel. Made from aluminum alloy, these file cabinets weigh up to 50% less than steel designs. The lightweight quality makes aluminum file storage easier to move and reposition. Aluminum still provides reasonable durability for office use.

Stainless Steel File Cabinets

Stainless steel contains chromium that gives it attractive shine and luster. It is also extremely durable and rust-resistant. Stainless steel file cabinets convey a modern, high-end aesthetic. However, stainless steel models come at a premium cost over standard steel.

Laminate and Wood Veneer Options

The exterior surfaces of metal file cabinets are typically coated or laminated:

Laminate Coatings

Powder coating and spray-on finishes are commonly applied to metal filing cabinets. These laminate layers provide aesthetic appeal in any color along with protection of the underlying steel. Common options include neutral tones like beige and gray as well as bold colors like red and black. Gloss and matte textures are also available.

Wood Veneers

Real wood veneers consisting of thin sheets of wood can be adhered to metal filing cabinets to achieve an elegant wooden look. Popular veneer options include oak, cherry, maple, walnut, and mahogany. Wood laminates and plastic laminates imitating wood grains are also used.

Locking Mechanisms and Drawer Slides

Several important components contribute to the internal functionality of metal filing cabinets:

Locking Systems

Most filing cabinets incorporate locking rods or interlocking drawer designs for security. Keyed locks, combination locks, and electronic locks are common options. High-security locks prevent unauthorized entry.

Drawer Slides

Drawer slides, roller glides, or drawer rails allow smooth opening and closing of drawers even when heavily loaded with files. Ball bearing slides and full extension slides provide maximum usability. High quality slides enable effortless access and protection of contents.

Hanging Folder Frames

Special frames inside drawers allow hanging folders to be suspended vertically and accessed easily. These metal frames maximize drawer space for folders.

Not Always 100% Steel

With the variety of metals, veneers, laminates, and other materials used in parts of metal file cabinet constructions, most are not literally made 100% of steel. But steel does comprise the bulk of the structural framing and offers the greatest benefits for strength, fire resistance, and cost savings versus other metals. It provides the fundamental component bringing the key attributes of durability, security, and functionality to quality metal file storage cabinets.

What Steel Grades Are Used in File Cabinets?

Not all steel is created equal. There are numerous grades and formulations of steel tailored to specific applications and performance requirements. When it comes to manufacturing file cabinets, some key steel grades rise above the rest as optimal choices.

Common Steel Grades for File Cabinets

Here are some of the most popular steel types used to fabricate filing cabinet frames and bodies:

• Cold Rolled Steel – This is steel that has been processed by rolling passes at room temperature to improve its strength and surface finish. It provides a nice smooth foundation for coatings.
• Mild Steel – Contains relatively low carbon levels, making it easy to form and weld. It strikes a balance between strength, ductility, and cost.
• Electrogalvanized Steel – Has a zinc coating applied via electrical current to resist corrosion. Provides protection during manufacturing.
• Hot Rolled Steel – Rolled at high temperatures to soften and shape it. Offers good strength at a reasonable price point.
• Stainless Steel – Alloys like 304 and 430 stainless add nickel, manganese, and chromium to improve corrosion resistance, albeit at a higher cost.

Key Steel Properties That Matter

These particular steel types work well in filing cabinets because they possess the ideal properties:

Strength

File cabinets need sufficient strength to protect documents without warping, bending, or breaking with repeated use. Minimum yield and tensile strengths of about 30,000-50,000 psi work well.

Formability

The steel needs enough ductility to be bent, pressed, and manipulated into file cabinet components without cracking or failing.

Weldability

Multi-part file cabinet bodies must be welded together cleanly. Steels with low carbon and sulfur facilitate strong welds.

Coating Adhesion

Powder coats, paints, and laminates need to bond tightly to the steel surface to avoid chipping and peeling issues.

Cost

Affordability is essential for mass production. Standard hot rolled and cold rolled steels offer the best balance of performance and price.

Why Low Carbon Steels Dominate

Steels with lower carbon percentages, like hot rolled, cold rolled, and mild steel, offer the optimum combination of strength, formability, weldability, and cost-efficiency. Higher carbon steels are stronger but more expensive and difficult to fabricate. Stainless steels improve corrosion resistance but are overkill for indoor file cabinet use.

Low carbon steels hit the sweet spot between performance, durability, and budget-friendly production. That makes them the go-to choice for constructing affordable but sturdy metal filing cabinets suitable for both home and office use.

What Thickness of Steel Is Used in File Cabinets?

The steel sheet metal used to fabricate the cabinets must be thick enough to provide sufficient structural integrity without being overly heavy. Most quality file cabinets utilize steel in the range of 16 gauge to 22 gauge thickness. This provides the right balance of strength and affordability.

Steel Thickness Measurements

Steel thickness used in manufacturing is measured in gauges. The lower the gauge number, the thicker the steel. Here is an overview of common gauge measurements:

• 10 gauge – Approximately 1/8 inch thick
• 14 gauge – Approximately 1/16 inch thick
• 16 gauge – Approximately 0.06 inch thick
• 18 gauge – Approximately 0.05 inch thick
• 20 gauge – Approximately 0.04 inch thick
• 22 gauge – Approximately 0.03 inch thick

Thinner 24 or 26 gauge steel is too flimsy for filing cabinets. Thicknesses below 16 gauge become excessively heavy.

Key Factors in Choosing Thickness

The ideal steel gauge depends on a few key factors:

Sturdiness

Thicker steel provides enhanced sturdiness and impact resistance, preventing dents. But it also makes the cabinets much heavier.

Fire Resistance

Thicker steel withstands fire better. But most home/office use doesn’t require extreme fire ratings.

Weight

Excessively thick steel makes cabinets difficult to move and reposition. Lighter cabinets with thinner steel are desirable for easy handling.

Cost

Thicker steel adds costs. Thinner steel saves on materials and shipping.

16 to 22 Gauge – The Sweet Spot

Given all these considerations, most manufacturers find 16 to 22 gauge steel optimal for standard file cabinets:

• 16 gauge – Provides sturdy protection from dents and impact damage thanks to the thicker 1.6mm steel. But weight is still reasonable at around 130-180 lbs when full.
• 18 gauge – Very popular choice that makes cabinets lightweight for easy mobility at around 100-140 lbs full, yet durable enough for office use.
• 20 gauge – Slightly more prone to dents but still sufficiently sturdy for home office applications. Excellent choice for minimizing weight (70-100 lbs). Very affordable.
• 22 gauge – Approaching the lower limit for acceptable sturdiness and fire ratings, but enables very light cabinet weight (50-70 lbs).

Within this range, buyers can choose the ideal balance of affordability, weight, and strength suited to their specific home or office needs.

Main Manufacturing Processes for Metal File Cabinets

Constructing quality metal file cabinets involves manufacturing processes such as forming, cutting, welding, surface finishing, and assembly. Each process contributes to efficient fabrication and customizability.

Forming the Steel Components

Steel parts like panels, drawers, and frames begin as sheet metal coils. Computer-controlled machines transform the coiled steel into properly shaped components.

Popular forming methods include:

• Roll forming – Steel sheets are passed through consecutive rollers that bend and form the metal into precise 3D shapes. Efficient for high volume production.
• Press braking – A press brake machine bends and forms sheets using male and female dies and hydraulic pressure. Versatile for lower volume runs.
• Stamping – Steel is stamped between matched male/female dies to cut, emboss, and form features and holes. Quickly creates complex, consistent parts.

Cutting and Drilling

Once formed, additional machines trim and cut the steel into final parts:

• Laser cutting – A high-precision laser cuts complex profiles from sheet metal while avoiding wear of mechanical blades.
• Punching – Punch presses use shaped punches to stamp clean holes rapidly with minimal waste.
• Shearing – Shears cut steel to width and length for final sizing and edging.
• CNC Machining – Computer numerical control mills and drills create custom holes and features.

Welding and Joining

For multi-part cases, the formed steel components get welded together:

• Spot welding – Robotic spot welders rapidly fuse overlapping pieces at fixed points.
• MIG welding – Continuous wire-feed welders provide full seam welds with inert gas shielding.
• Adhesives – Adhesives help reinforce and fill seams.

Finishing Processes

Surface finishing steps complete the fabrication:

• Deburring – Edges are polished to remove sharp burrs and smooth surfaces.
• Powder coating – Electrostatically applied powder creates colorful, durable exterior finishes.
• Laminating – Thin laminates add aesthetics like realistic woodgrains.

Hardware Insertion and Assembly

Finally, all the cabinet hardware gets installed:

• Hinges, drawer slides, and locks get inserted into pre-formed attachment points.
• Contents like file frames and dividers get mounted within the case interior.
• Drawers are attached to the slides and chassis.
• Doors are mounted to hinges and adjusted.

Proper manufacturing techniques allow high quality file cabinets to be mass produced efficiently while maintaining precision and consistency. Consistent quality ensures years of reliable service life.

Processes for Applying Finishes to Metal File Cabinets

The outer finish completes a metal file cabinet’s look while protecting the underlying steel. Several processes can apply both decorative and functional coatings:

Powder Coating

Powder coating is the most common finishing process used on metal file cabinets:

• The steel is first cleaned and pretreated to improve powder adhesion.
• The cabinet is then sprayed electrostatically with a colored polymer powder.
• The powder is cured under heat to melt, flow, and harden into a smooth, durable finish.

Benefits

Powder coating offers many advantages:

• Attractive glossy or matte look in virtually any color.
• Excellent durability and scratch resistance.
• Consistent automated application minimizes quality issues.
• Environmentally friendly process with minimal VOCs.

Limitations

Powder coating does have some downsides:

• Doesn’t provide the rich depth of real wood laminates.
• Can show signs of wear over time, especially on handles.
• Upfront equipment costs make in-house powder coating prohibitive for low volumes.

Wet Spray Painting

Liquid paints can also be spray-applied and baked to cure:

• Spraying allows coating of complex cabinet geometries.
• Skilled painters can achieve high quality decorative finishes.
• Provides similar durability to powder coating.

Drawbacks

The disadvantages of liquid painting include:

• More environmentally harmful VOC emissions.
• Requires significant manual effort by skilled painters.
• Runs and drips can easily occur if not applied carefully.
• Air bubbles in the finish are common.
• Color matching between batches can be inconsistent.

Wood Laminates

Real wood veneers or laminates offer an elegant finish:

• Thin sheets of natural wood are bonded to the steel.
• Synthetic laminates imitate woodgrain patterns.

Benefits

• Provides warmth and aesthetics of real wood at lower cost.
• Variety of wood species and stains available.
• Alternative to painted finishes.

Limitations

• Not as durable as powder coating and more prone to scratching or damage over time.
• Darker real wood finishes show dust buildup readily.
• Not well suited for painting or re-coating later if damaged.

Overall, powder coating delivers the best combination of appearance, durability, and cost-effectiveness for most high-volume metal file cabinet manufacturing.

How Sheet Metal Parts Are Cut and Formed into File Cabinet Components

Transforming raw sheet metal into the precisely formed parts of a file cabinet is a fascinating process accomplished through cutting, punching, bending, and stamping operations.

Cutting Metal to Size

Large coils of flat sheet metal are first cut down to workable sizes:

• Mechanical shearing uses straight blades to cut sheets to length and width.
• CNC laser cutting ensures maximum precision and complexity in profiles.

Punching Holes

Punch presses utilize shaped punches and dies to cleanly stamp holes of any shape in seconds while the metal is still flat:

• Attachment holes allow joining of separate panels.
• Lock holes accommodate installation of locking hardware.
• Ventilation holes facilitate airflow.
• Handle holes provide ergonomic access points.

Forming and Bending

Specialized machines then form the sheared and punched flat blanks into 3D preformed parts:

• Press braking presses sheet metal between male and female dies to create precise bends and edges.
• Roll forming uses a series of rolling dies to gradually bend metal into curved profiles.
• Stamping employs male and female dies to form 3D cavities and protrusions.

Fabricating Specific Components

These processes transform sheet metal into the individual components:

• Major side panels, top panels, and drawer bodies take shape through bending and flattening operations.
• Drawer slides get roll formed for smooth function.
• The drawer handle gets precisely punched and bent up from flat stock.
• The front frame is stamped for consistency across production runs.
• Hinge plates are blanked and formed for sturdy door attachment.

Automated machines churn out each part rapidly while maintaining strict tolerances for proper assembly. Skilled technicians program the proper sequencing of manufacturing steps to make each part. The result is intricately transformed sheet metal ready for assembly into the final file cabinet.

How Are the Metal File Cabinet Frame and Chassis Assembled?

Once the precisely fabricated sheet metal components are complete, they are ready to be joined together to form the main file cabinet chassis and frame. Careful welding and mechanical fastening produce the core structure.

Frame Assembly

The cabinet requires a surrounding steel frame for structural rigidity:

• The side panels, top panel, bottom panel, and back panel get aligned and spot welded in place.
• Corner brackets also strengthen the joints.
• Spot welds spaced a few inches apart ensure sturdy connections without warping.

Chassis Weldment

The interior chassis provides mounting points for drawers:

• The chassis consists of front-to-back rails and cross-braced slide supports.
• Rails get fully MIG welded for seamless joints.
• Slide supports