Measure with Precision: Finding the Best Combination Square for You

A combination square is an essential woodworking tool that every workshop should have. This versatile tool allows you to mark 45- and 90-degree lines, measure material thickness, and ensure workpieces are square. With many options on the market, choosing the right combination square depends on your budget and needs. The highest-rated combination squares are made by premium brands like Starrett and iGaging, known for their durability, precision, and smooth sliding mechanisms.

The Starrett Steel C11H-12-4R combination square is considered the best overall by woodworking experts. Its forged steel head provides unmatched lifetime accuracy. For most DIYers, the Irwin 1794469 12-inch model strikes the ideal balance of quality and price. Both options have durable metal bodies with clearly etched imperial markings. iGaging also makes excellent affordable squares with up to 1/64” precision. Other top brands like Swanson and Johnson Level & Tool offer quality etched blades and smooth adjustments for lower prices.

When selecting a combination square, pay attention to the head material, rule length, locking mechanism, measurement markings, and overall accuracy. The head should be steel, not plastic or aluminum. Common rule lengths are 6 and 12 inches. Precisely etched markings are preferable to stamped. And above all, the square must consistently measure 90 and 45 degrees with minimal deviation. With so many choices, you can find the ideal combination square to suit your budget and projects. Investing in a quality model from a reputable brand will provide years of reliable service in your woodshop.

Best Combination Squares

Product Key Features
Irwin 12″ Combination Square – Best for most people
– Durable aluminum head
– Etched imperial markings
iGaging 4R Series – Most affordable
– Premium accuracy
– Machined steel head
Starrett C11H-12-4R – Top choice of experts
– Maximum precision
– Cast iron head
  • Irwin 12-inch – This combination square strikes the ideal balance of price and performance for most DIYers. The aluminum head provides durability while keeping the weight manageable. The 12-inch etched steel rule gives clear imperial measurements. The locking mechanism is a bit loose but gets the job done. For the price, it’s hard to find a better all-around combination square.
  • iGaging 4R Series – For an accurate yet affordable option, the iGaging combination squares can’t be beat. The machined steel head and premium etched blade offer incredible precision at a budget-friendly price point. The slide lock provides a smooth and secure fit. If you want the quality of a premium brand without the high cost, iGaging is the way to go.
  • Starrett C11H-12-4R – If money is no object, this model is considered the best of the best. The cast iron head and finely honed rule deliver unmatched precision within 0.001″. The slide lock mechanism provides the smoothest adjustment of any square. The Starrett square will last a lifetime if cared for. While expensive, it’s worth the investment for the most demanding woodworkers.

Other top choices include the WORKPRO rafter & combination square set, Mr. Combination Square, and the IRWIN 6-inch & 12-inch combination set. The WORKPRO set provides both a rafter square and 12″ combination square at a bargain price point. Mr. Combination Square is praised for its clever two-sided etched imperial/metric rule. And the IRWIN 6-inch & 12-inch set bundles two popular sizes at an affordable cost.

Combination Square Uses

A combination square is one of the most versatile tools to have in a woodworking shop. Here are some of the most common uses:

  • Marking 90° lines – The head allows you to mark straight lines perpendicular to an edge. This aids in ripping boards and cutting joinery.
  • Marking 45° lines – The head also marks 45° angles for miter joints.
  • Measuring thickness – Set the rule to the thickness and lock it to transfer the measurement.
  • Checking for square – Verify that edges are at true 90° angles.
  • Gauge setup – Set tools like table saw blades and router bit heights.
  • Layout lines – Transfer measurements for drawers, boxes, etc.
  • Ensuring stock is straight – Use the edge to check wood boards for twist or bowing.
  • Finding center of stock – Mark center lines on boards for turning operations.

As you can see, a combination square has a place in nearly every woodworking operation. Keep one near your work area for frequent access and use.

What to Look for When Buying

With many combination squares to choose from, here are the key factors to consider:

  • Accuracy – This is the most crucial factor. A combination square must accurately mark 90° and 45° angles. Tolerances up to 0.005′′ are acceptable. Test the square when you first get it and return if it’s inaccurate.
  • Materials – The head should be steel or cast iron to prevent twisting. Rules with etched markings are easiest to read after years of handling. Avoid plastic components if possible.
  • Size – 6-inch squares are ideal for smaller workpieces, while 12-inch models allow wider layout lines. Make sure the rule is long enough for your largest stock.
  • Locking mechanism – A smooth, secure slide lock makes adjustments effortless. Look for a knurled knob that won’t slip.
  • Markings – Rules with etched imperial and/or metric markings are preferred for durability. Font size should be easy to read.
  • Extras – Some squares include useful bonuses like a level vial for angled stock or a scoring awl for marking lines.
  • Price – Expect to pay $10-$100. Higher prices bring more precision but provide minimal added benefit.
  • Brand reputation – Stick with trusted brands like Starrett, Swanson, and Johnson. Check reviews as well.
  • Warranty – Many quality squares have a 1 year warranty or more. This protects against defects.
  • Made in USA – Look for American-made models if supporting domestic manufacturing is important to you.

By keeping these factors in mind as you shop, you’ll be equipped to select the ideal combination square for your needs and budget.

Top Brands

Some of the leading combination square manufacturers include:

  • Starrett – The Starrett brand is synonymous with precision measurement tools. Their combination squares represent the gold standard for accuracy. The phased cast iron heads prevent twisting and their slide locks adjust smoothly. Starrett is a USA-made product.
  • iGaging – This relative newcomer has quickly built a reputation for affordable precision. Their combination squares perform well above their price point. The machined steel heads stay true and the etched blades are easy to read. iGaging tools are made in China.
  • SwansonSwanson has been producing combination squares and rules for over 100 years. Their squares offer solid performance at a reasonable cost. While not as refined as premium brands, Swanson is perfect for the casual woodworker. Made in the USA.
  • Johnson Level & Tool – Known for levels, Johnson also makes capable combination squares at budget prices. The aluminum heads aren’t as robust but get the job done. Johnson squares are manufactured in China.
  • Irwin – Part of Newell Brands, Irwin offers a range of combination squares for DIYers. Most feature durable aluminum heads and accurate etched rules. Irwin strives for decent quality at affordable made-in-China price points.
  • Empire – Empire Level Manufacturing specializes in construction layout tools. Their combination squares have a good reputation, especially for the cost. Many Empire products are made in the USA.

Using a Combination Square

Combination squares provide many functions but must be used properly to achieve accurate results:

  • Line drawing – For straight lines, press the head against the edge of the stock. Lock the rule at the desired distance. Use a knife to slice along the rule edge.
  • Measuring – Make sure the rule is firmly locked to take measurements. Don’t move the head when transferring readings.
  • Checking for fit – When marking across a surface, lock the rule and pivot only the head for precise fit.
  • Accuracy – Check the square periodically for 90° and 45° accuracy. Don’t rely on slightly inaccurate tools.
  • Secure stock – Hold the stock firmly against a stop block when using the square. This prevents slipping.
  • Mind the extrusions – Don’t bump the adjustment nut or level vial to throw off the tool’s accuracy.
  • Protect the surfaces – Avoid dropping the square or scraping it against abrasives. This maintains the precision.
  • Check for wear – Look for any wobble in the head-rule connection. This indicates loosening that affects performance.

Following these tips will ensure you get reliable results from a combination square for years to come. Don’t underestimate this humble but versatile woodworking tool!

Maintaining a Combination Square

With periodic care, a quality combination square will deliver decades of accurate service:

  • Clean surfaces – Wipe off any rust, grime, or oil that accumulates on the surfaces. This prevents buildup.
  • Lubricate slide – Use a dry lubricant spray on the slide joint. This keeps the action smooth.
  • Inspect locking nut – Check that the nut turns smoothly and keeps the rule secure. Replace if needed.
  • Verify 90° – Periodically check that the head marks an accurate 90° angle to the rule.
  • Confirm 45° – Check that the 45° notch on the head lines up properly with the rule.
  • Store properly – Keep the square in a tool chest or hanging on a wall hook. Don’t let it roll around loose.
  • Refinish as needed – If oxidation appears on the steel, use emery cloth and oil to restore the surfaces.
  • Replace broken parts – Contact the manufacturer if any components like the rule become damaged or lost.

With minimal maintenance, a high-quality combination square should stay in alignment and provide accurate markings and measurements for a lifetime. Don’t let this inexpensive tool be an afterthought – take good care of it!

Combination Square Techniques

Beyond the basics, there are some specialized techniques that combination squares can enable:

  • Offset lines – Place thin shims between the square and stock to mark parallel offset lines.
  • Circle marking – Tack the square at a set radius from the center to mark circular cuts.
  • Angle duplication – Mark an angled line, then pivot the square to transfer the angle.
  • Joint layout – Use an adjustable square to mark the same mortise and tenon shoulders on multiple pieces.
  • Row marking – Clamp a straight board to use the square edge to mark identical layout lines.
  • Circle dividng – Mark precise divisions on a circular piece by using the square against a straightedge.
  • Marking duplicate parts – Set the rule to mark matching components like chair legs without measuring each time.

With creativity, a combination square’s uses are virtually limitless. Explore ways to incorporate it into more complex woodworking operations.

Alternatives to Combination Squares

While indispensable in most workshops, combination squares aren’t the only option:

  • Speed square – Thinner and more compact for quick 90 and 45 degree marking tasks.
  • Try square – Larger all-steel squares with precision-ground edges for layout.
  • Drafting square – Oversize triangles perfect for drawing long straight edges on oversized stock.
  • Framing square – Two-foot steel squares for construction and timber framing tasks.
  • Digital angle finder – Electronic angle finder that can dial in any custom angle.
  • Sliding T bevel – Adjustable blade allows marking any angle needed. Locks to transfer angles.
  • Protractor – Plastic circular protractors ideal for measuring and marking angles.

Each has advantages in certain situations depending on the demands of the application. But for general woodworking, the classic combination square is still hard to beat!

Frequently Asked Questions

What are the main uses of a combination square?

The main uses are marking perpendicular lines, checking for square, measuring thicknesses, setting saw blade heights, marking angled lines, transferring measurements, and aligning stock.

What size combination square should I get first?

A 12-inch combination square is the most versatile size for general woodworking tasks. It allows you to work with wider stock pieces.

Should I buy plastic or metal combination squares?

Metal combination squares are more durable and precise. The head and rule should be steel or cast iron. Avoid plastic components if possible.

How can I check if a combination square is accurate?

Test it by marking lines on a known straight piece of scrap. Flip the square and mark again. Compare the lines to see if they perfectly align.

Why is the rule loose and slipping on my combination square?

Tighten the locking nut or knob to securely hold the rule. If that doesn’t work, dirt or wear may require you to replace components.

What is the best way to clean a combination square?

Wipe off any grime with a soft cloth. Remove rust with emery paper. Lubricate the sliding joint with a dry lubricant spray.

Should I oil or grease the sliding surfaces?

No, use a dry lubricant instead of oil/grease which can attract sawdust and grime. Periodically reapply the dry lubricant.

How can I check if my combination square is still at perfect 90 degrees?

Verify with an engineer’s square, machined straightedge, or by marking perpendicular lines on a flat board.

Where is the best place to store a combination square?

Keep it in a dedicated tool chest drawer or hanging on a wall hook. Don’t allow it to roll around loose in a toolbox.

How much should I expect to pay for a quality combination square?

Budget $20-50 for a decent square with machined steel components. Higher priced premium squares over $75 offer slightly better precision.

The Bottom Line

In conclusion, selecting the best combination square is an essential step for any craftsman or DIY enthusiast striving for precision in their projects. With the options highlighted in this guide, you’ve gained insights into some of the top choices available, each offering unique features to cater to your specific needs. Whether it’s woodworking, metalworking, or general layout tasks, the right combination square can be your trusted companion in achieving accurate measurements and angles.

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