Hey guys! Let's dive into the world of Starrett combination squares. These tools are incredibly versatile, but understanding their parts is crucial for accurate work and proper maintenance. Whether you're a seasoned woodworker, metalworker, or just a DIY enthusiast, knowing the ins and outs of your Starrett combination square will definitely up your game.

Understanding the Main Components

The Starrett combination square isn't just one piece; it's a system of interconnected parts that work together to give you precise measurements and layouts. Let's break down each component:

The Blade (or Rule)

At the heart of the combination square is the blade, sometimes referred to as the rule. This is the long, slender, typically steel portion that features precise graduations for measuring. The blade's quality is paramount; a high-quality blade ensures accuracy and longevity. Starrett blades are known for their exceptional clarity and durability. They're made to withstand wear and tear, giving you reliable measurements for years. The graduations are usually etched or laser-marked, providing clear and easy-to-read markings. Different blades come in various lengths, such as 6 inch, 12 inch, or even longer, catering to different project needs. When selecting a blade, consider the types of measurements you'll be making most frequently. For detailed work, finer graduations are preferable, while larger projects might benefit from a longer blade. Always keep your blade clean and lightly oiled to prevent rust and maintain its accuracy.

The Square Head

The square head is one of the key attachments that slides onto the blade. Its primary function is to provide a precise 90-degree angle for marking and checking squareness. A well-made square head will sit perfectly perpendicular to the blade, ensuring accurate layouts. The square head typically features a hardened steel face that resists wear, maintaining its precision over time. It also usually includes a spirit level, which allows you to check for level or plumb. This adds another layer of versatility to the combination square, making it a valuable tool for various tasks. Some square heads also have a scriber, a small pin used for marking lines on your workpiece. The scriber is usually stored within the square head and can be easily accessed when needed. When using the square head, always ensure it's firmly seated against the blade and that the locking mechanism is secure. This prevents any movement that could compromise your measurements. Regularly check the squareness of the head against a known accurate reference to ensure it remains true.

The Protractor Head

The protractor head expands the combination square's capabilities by allowing you to measure and mark angles other than 90 degrees. This attachment typically features a rotating dial with degree markings, allowing you to set the desired angle accurately. The protractor head is incredibly useful for a variety of tasks, such as cutting miters, creating angled joints, or checking the angles of existing structures. Like the square head, the protractor head slides onto the blade and is secured with a locking mechanism. The accuracy of the protractor head depends on the precision of its dial and the tightness of its locking mechanism. When using the protractor head, make sure the dial is properly calibrated and that the locking mechanism is fully engaged to prevent slippage. Some protractor heads also include a spirit level, which can be helpful for ensuring accurate angle measurements, especially when working on vertical surfaces. The protractor head greatly enhances the versatility of the combination square, making it an indispensable tool for any serious craftsman.

The Center Head

The center head is a specialized attachment designed to locate the center of round stock accurately. This is particularly useful for metalworkers and machinists who frequently work with cylindrical materials. The center head features two arms that form a V-shape, which, when placed against the round stock, allows you to draw a line that passes directly through the center. To use the center head, simply place the round stock within the V-shaped arms and slide the head along the blade until it's centered. Then, use a scriber or pencil to draw a line along the edge of the blade. Rotating the round stock by 90 degrees and repeating the process will give you two intersecting lines that pinpoint the exact center. The accuracy of the center head depends on the precision of its V-shaped arms and the straightness of the blade. Ensure the arms are clean and free of debris before use to maintain accuracy. The center head simplifies the process of finding the center of round stock, saving time and ensuring precision in your work.

Additional Components and Accessories

Beyond the main components, several smaller parts and accessories contribute to the functionality and versatility of the Starrett combination square:

Locking Mechanisms

The locking mechanisms are crucial for securing the heads to the blade at the desired position. These mechanisms vary depending on the model but typically involve a setscrew or a clamp that tightens against the blade. A reliable locking mechanism ensures that the head remains firmly in place, preventing any movement that could compromise the accuracy of your measurements. Over time, these mechanisms can wear down or become loose, so it's essential to inspect them regularly and tighten them as needed. Some locking mechanisms also include a fine-adjustment feature, allowing you to make precise adjustments to the head's position. When tightening the locking mechanism, avoid over-tightening, as this can damage the blade or the head. A firm, snug fit is usually sufficient to hold the head securely in place. The quality of the locking mechanism is a key indicator of the overall quality of the combination square.

Spirit Levels

Many square heads and protractor heads include spirit levels, also known as bubble levels. These levels allow you to check for level or plumb, adding another layer of functionality to the combination square. The spirit level consists of a small vial filled with liquid, usually alcohol or mineral spirits, and a bubble. When the bubble is centered between the markings on the vial, it indicates that the surface is level or plumb. Spirit levels are particularly useful when installing shelves, hanging pictures, or ensuring that structures are perfectly vertical. To ensure accuracy, spirit levels should be calibrated regularly. You can check the calibration by placing the level on a known level surface and noting the position of the bubble. Then, rotate the level 180 degrees and see if the bubble remains in the same position. If it doesn't, the level needs to be adjusted. The presence of a spirit level enhances the versatility of the combination square, making it an even more valuable tool for a wide range of tasks.

Scribers

Some combination squares come with a scriber, a small, hardened steel point used for marking lines on your workpiece. The scriber is usually stored within the square head and can be easily accessed when needed. Scribers are particularly useful for marking lines on metal or other hard materials, where a pencil might not leave a clear mark. To use the scriber, simply hold it against the edge of the blade and drag it along the surface of the workpiece. Apply firm, even pressure to create a clear, precise line. When not in use, the scriber should be stored safely to prevent damage or injury. Some scribers are replaceable, allowing you to swap out a dull or damaged point with a new one. The inclusion of a scriber adds to the versatility of the combination square, making it a valuable tool for both woodworking and metalworking.

Maintaining Your Starrett Combination Square

Proper maintenance is key to ensuring the accuracy and longevity of your Starrett combination square. Here are some tips to keep your tool in top condition:

• Cleaning: Regularly clean the blade and heads with a soft cloth to remove dust, dirt, and grime. For stubborn residue, use a mild solvent or degreaser.
• Oiling: Apply a light coat of oil to the blade and moving parts to prevent rust and corrosion. Use a high-quality oil specifically designed for tools.
• Storage: Store your combination square in a dry, safe place to protect it from damage. Consider using a case or sheath to prevent scratches and dents.
• Calibration: Periodically check the squareness of the square head and the accuracy of the protractor head. Make adjustments as needed to ensure precise measurements.
• Inspection: Regularly inspect all parts for wear and tear. Replace any damaged or worn parts to maintain the tool's accuracy and functionality.

Troubleshooting Common Issues

Even with proper maintenance, you might encounter some common issues with your Starrett combination square. Here are some troubleshooting tips:

• Loose Locking Mechanism: If the locking mechanism is loose, tighten the setscrew or clamp. If the mechanism is worn, consider replacing it.
• Inaccurate Square Head: If the square head is not square, adjust the head or replace it. You can use a precision square to check for squareness.
• Sticking Blade: If the blade is sticking, clean and oil it. Make sure there is no debris obstructing the movement.
• Damaged Graduations: If the graduations on the blade are damaged, consider replacing the blade. Accurate graduations are essential for precise measurements.

Conclusion

So, there you have it! A comprehensive look at the parts of a Starrett combination square. Understanding each component and how they work together is essential for getting the most out of this versatile tool. With proper care and maintenance, your Starrett combination square will be a reliable companion in your workshop for years to come. Now go out there and make some accurate measurements!