Folding Squares

About Folding Squares

Folding squares are indispensable precision measuring tools that combine portability with accuracy, making them essential equipment for carpenters, joiners, roofers, and metalworkers throughout the UK. These cleverly designed layout tools feature two or more arms connected by a hinged mechanism that allows them to fold completely flat for easy storage and transport, yet open to provide reliable 90-degree angles for marking, checking squareness, and measuring both inside and outside corners. Unlike fixed try squares or engineer's squares, folding squares can be tucked into a tool belt, work apron, or trouser pocket, making them ideal for site work where space is at a premium and tools need to be readily accessible.

Modern folding squares are typically constructed from lightweight aluminium alloy with anodised or powder-coated finishes that resist corrosion and wear in demanding site conditions. The arms feature clearly marked graduations in metric measurements, with many models offering dual imperial and metric scales for added versatility. Quality examples from brands like Stanley, Hultafors, and Faithfull include secure locking mechanisms that hold the square firmly at 90 degrees during use, whilst allowing smooth folding action when needed. Blade lengths typically range from 200mm to 300mm, providing sufficient reach for most joinery, roofing, and construction applications without becoming unwieldy.

The folding square remains one of the most practical layout tools available at Tooled-Up.com, offering excellent value and durability for both professional tradespeople and DIY enthusiasts. Whether you're setting out roof rafters, checking door frames for square, marking accurate cut lines on sheet materials, or verifying corner angles in metalwork, a well-made folding square delivers the precision you need whilst fitting comfortably in your work gear. Many modern models also incorporate additional features such as 45-degree angles and spirit levels, transforming them into versatile combi angle squares suitable for multiple measuring and marking tasks.

Jargon Buster

True 90-Degree Angle

The guaranteed perpendicular accuracy of the square's arms when locked open, typically manufactured to within 0.5mm tolerance over the blade length. Essential for ensuring accurate joinery and layout work.

Anodised Aluminium

Aluminium that has undergone an electrochemical process to create a hard, corrosion-resistant surface layer. This finish protects the square from UK site conditions and prevents measurement markings from wearing off prematurely.

Blade and Stock

The two main components of a folding square – the longer 'blade' provides the measuring scale, whilst the shorter 'stock' forms the handle and reference edge when marking or checking squareness.

Etched Graduations

Measurement markings that are chemically etched or laser-engraved into the metal surface rather than merely printed. This ensures the scales remain legible even after years of heavy site use.

Locking Mechanism

The hinge system (often featuring a wing nut, lever, or friction joint) that secures the square in its open position, preventing movement during marking or checking operations.

Combi Angle Square

A folding square that incorporates additional features such as 45-degree angles, spirit levels, or integrated protractors, making it a multi-purpose layout tool rather than a single-function square.

Who Uses Folding Squares?

Folding squares serve a wide range of trades and applications:

• Carpenters and Joiners: Essential for checking door frames, marking timber cuts, setting out stairs, and verifying corner squareness in all types of woodworking projects
• Roofers: Invaluable for calculating and marking rafter angles, checking square on roof structures, and ensuring accurate cuts on fascia boards and verges
• Shop Fitters and Kitchen Installers: Vital for ensuring cabinets, worktops, and display units are installed square and true to prevent fitting issues
• Builders and General Contractors: Used throughout construction projects for checking wall corners, setting out foundations, and verifying structural squareness
• Metalworkers and Fabricators: Helpful for marking cutting lines on sheet metal and verifying right angles in fabrication work
• Dry Liners and Plasterers: Regular use when installing stud walls, checking partition frames, and ensuring plasterboard installations are square
• Tilers and Floorers: Perfect for setting out tile layouts, checking corners, and marking accurate cuts on ceramic and stone materials
• DIY Enthusiasts: Ideal for home improvement projects including decking installation, shed building, shelving, and furniture assembly where accurate 90-degree angles are crucial

How to Choose the Right Folding Squares

Material and Construction: Aluminium alloy offers the best combination of light weight, strength, and corrosion resistance for UK site work. Look for anodised finishes on quality models from manufacturers like Stanley, Hultafors, and Faithfull. Check that rivets and hinges are solidly constructed – these are the most vulnerable points on any folding square.

Blade Length: Most folding squares feature blade lengths between 200mm and 300mm. A 300mm blade offers greater reach and is ideal for checking larger frames or marking longer boards, whilst 200mm models are more compact for tight spaces and easier to carry in your work apron. Consider the typical scale of your work when choosing.

Accuracy and Tolerances: Professional-grade squares from brands like Hultafors typically guarantee accuracy to within 0.5mm over the blade length. Check product specifications for stated tolerances – cheaper models may lack this information, suggesting less rigorous manufacturing standards. For precision joinery, tighter tolerances are essential.

Locking Mechanism: A secure, easy-to-operate lock is essential for reliable measurements. Wing nut systems offer positive locking but can loosen over time with repeated use, whilst friction hinges maintain consistent pressure but may eventually wear. The mechanism should hold firmly without play yet open and close smoothly throughout the tool's lifespan.

Scale Graduations: Look for clearly marked metric graduations that are etched or laser-engraved rather than printed. The markings should be legible from various angles and sufficiently detailed for your work – typically 1mm increments. Some squares feature scales on both sides of the blade for added convenience when marking from either direction.

Additional Features: Some models incorporate 45-degree angles, small spirit levels, or scribe guides, transforming them into combi angle squares. Whilst these add versatility, ensure the additional features don't compromise the primary 90-degree accuracy or make the tool unnecessarily bulky for your tool belt.

Popular Accessories

• Combination Squares: Complement your folding square with a combination square featuring a sliding blade for internal measurements and depth marking
• Try Squares: Fixed-angle squares for workshop use where folding isn't required and maximum rigidity is preferred
• Carpenters' Pencils: Flat pencils designed for marking timber and building materials, essential for using your square effectively on site
• Marking Knives: Provide finer, more accurate marking lines than pencils when used against the square's edge for precision joinery
• Spirit Levels: Use alongside your folding square to ensure components are both square and level during installation
• Tape Measures: A quality metric tape measure from brands like Stanley or Bahco works hand-in-hand with your folding square for complete measuring operations
• Engineer's Squares: For metalwork and workshop applications requiring even greater rigidity and precision than folding designs
• Tool Belts and Pouches: Dedicated pockets and holders keep your folding square protected and readily accessible on site
• Protractors and Angle Finders: For measuring and transferring angles beyond the standard 45 and 90 degrees

Frequently Asked Questions

What's the difference between a folding square and a try square?

A try square has a fixed 90-degree angle and doesn't fold, offering slightly better rigidity but significantly less portability. Folding squares sacrifice a small amount of rigidity for the convenience of folding flat, making them ideal for site work where tool belt space is limited and tools need to be easily transported. For most carpentry and construction applications, a quality folding square from manufacturers like Stanley or Hultafors provides more than adequate accuracy whilst being far more practical to carry throughout the working day.

How do I check if my folding square is still accurate?

Place your square against a perfectly straight edge (such as a steel rule or factory edge of plywood) and draw a line. Flip the square over and align it with the same line – if it's accurate, the blade will align perfectly with your drawn line. Any deviation indicates the square has lost its accuracy and should be replaced. This simple test should be performed periodically, especially if the square has been dropped or subjected to impact. Professional tradespeople should check accuracy every few months to maintain precision in their work.

Can folding squares handle UK site conditions and weather?

Quality folding squares with anodised aluminium construction are specifically designed for UK site conditions. They resist corrosion from moisture and won't rust like steel squares, making them suitable for outdoor use in typical British weather. However, you should still wipe them clean after use and avoid storing them in permanently damp conditions. The locking mechanisms may benefit from occasional lubrication with light machine oil to maintain smooth operation, particularly after exposure to wet conditions or dusty environments.

What blade length is best for general carpentry and joinery work?

For most carpentry and joinery applications, a 300mm blade provides the best versatility. This length offers sufficient reach for checking door frames, marking boards, and general layout work without being unwieldy or difficult to handle. Smaller 200mm models suit tight spaces and second-fix work but may feel limiting for first-fix carpentry or roofing applications. Consider investing in both sizes if you regularly work across different scales – the compact 200mm for fine work and the 300mm for general duties.

Are expensive folding squares worth the extra cost?

Professional-grade folding squares from brands like Hultafors or Stanley's premium range typically offer tighter manufacturing tolerances, more durable anodised finishes, and stronger locking mechanisms that maintain accuracy over years of use. For tradespeople using their square daily, the improved accuracy and longevity justify the investment – a quality folding square can last an entire career with proper care. DIY users undertaking occasional projects may find mid-range options from Faithfull or Draper available at Tooled-Up provide excellent value whilst maintaining acceptable accuracy for home improvement work.