Canadian Woodworking

Woodpeckers in-DEXIBLE standard combination square system

A comprehensive set of versatile, premium quality, high precision squares that will last a lifetime.


A comprehensive set of premium quality, versatile, high precision squares that will last a lifetime.

Author: Carl Duguay

Furniture and cabinet making is all about accuracy. Whether laying out or checking angles for your projects or setting up machinery you’ll do your best work with precision measuring and marking tools. And if you take care of these tools they’ll last a lifetime.

The new Woodpeckers in-DEXIBLE combination square system are essential everyday tools that will handle 90 percent of your measuring and layout tasks in the shop.



Manufacturer: Woodpeckers
Model: I-SDK-I
Price: $599.99 US (set of 4 heads, 3 blades)
Warranty: Limited lifetime; 30-day money back
Made in: USA



  • Heads: Combination, double square, protractor and center finder
  • Blades: 18″, 12″ and 6″
  • 4 Rack-It’s
  • Aluminum heads
  • Precision machined one-piece 11/128″ thick steel blades
  • Laser engraved scales graduated in 1/16″ or 1mm
  • Blades are bead blasted to produce a low sheen finish
  • Available with imperial or metric scales
  • Individual head and blade units available separately

The Woodpeckers in-DEXIBLE combination square system consists of four heads (combination, double square, protractor and center finder) and three blades (6″ 12″ and 18″). The heads and blades are interchangeable. Switching between them takes all of 10 seconds.

The fit and finish on these tools is superb. The heads are machined from a solid billet of aircraft grade aluminum and anodized for durability and reliability. The 1/16″ thick, 1-1/2″ wide, stainless steel blades are CNC machined engraved and then bead blasted to produce a low sheen finish that makes the laser-engraved scale very easy to read. And those markings will never wear off. Unlike squares with much thicker blades, these thinner blades really do reduce parallax errors (which occurs if you read a scale when you’re not looking perpendicular to the point of reference on the scale).

woodpecker indexable
Low sheen finish makes the scale very easy to read.

The measurement scale is graduated in 1/16″ increments one one side and 1/32″ on the opposite side and has two rows of laser-cut notches on 1/8″ centers that run the length of the blade. The notches are large enough to accommodate pencils, pens, fine tipped Sharpies and Pica-style mechanical pencils.  This makes it easy and quick to mark precise and consistent lines parallel to the edge of your stock. I’ve been using it to layout mortises, and it works like a charm.

woodpecker indexable
Thin blade reduces parallax errors yet is very rigid.

There is also a row of holes along the center of the blade that serve to index the head to the closest full inch. A spring-loaded pin on the head (hence the “in-DEXABLE” feature) registers the head on the blade. It’s useful for quickly setting the square to any whole number. The knurled steel locking knob is nice and chunky making it easy to tighten with fingertips.

woodpecker indexable
The in-DEXABLE pin registers the head on the blade.

Another innovative feature is the sliding tab (on the double and combo squares) that keeps the square flat on your stock. I find it particularly useful when using the longer (12″ and 18″) blades as the weight of the head invariably causes the head to fall downward.

woodpecker indexable
The sliding tab on the end of the head keeps the square flat on your stock.

If you work with a range of angle measurements then you’ll find this protractor invaluable. You can be forgiven for falling in love with this tool. It’s wonderfully designed, extremely precise, and a pleasure to use.  To set the blade at a desired angle you loosen two knurled knobs on the back of the head. You then rotate the head to the desired angle. There are short registration lines at every 1° and longer lines at every 5°. The head is nice and stiff when moving, which I especially like – it makes setting angles a lot easier than a loose head that flops back and forth. The protractor has presets, right and left of the beam, for the most frequently used angles — 22.5°, 45°, 67.5° and 90° — which you set by means of a small indexing pin on the back of the head.

woodpecker indexable
Large knurled head locking knobs.
woodpecker indexable
Presets at the most commonly used angles.
woodpecker indexable
Angles marked at 1° increments.

When installing built-in furniture I continue to use my contractor-grade squares. In the shop though, I reach for these Woodpecker squares.  They’re somewhat heavier than other similar squares I’ve used – 8-3/4 oz for the double square, 13 oz for the combo, 9 oz for the center finder and 1 lb 8 oz for the protractor – which gives them a solid feel in the hand. The aluminum bodies and stainless steel blades mean they’ll never rust, corrode or likely tarnish. And they’re deadly accurate.

The two squares I use almost every day are the 6″ double square and 12″ combo square. The double square, which gets the most use, is a tad too large to carry around in my apron – as with the combo square I leave it parked on my workbench. While the center finder’s primary function is to locate the center of round or square stock for lathe turning, I find it also works well as a depth gauge.

Woodpecker squares are competitively priced in relation to other premium brands, including Starrett and Mitutoyo. If you prioritize precision, durability and versatility, they’re worth the investment.

You can purchase the four squares as a set or separately – the protractor comes with a 18″ blade, the combination square comes with a 12″ blade and the double squares and center finder come with 6″ blades.

If  you do small scale work, or you just like smaller tools, there is an equivalent MINI in-DEXIBLE system that consists of the same four types of squares but in a compact size and length that will fit nicely in your shop apron.

woodpecker indexable


woodpecker indexable


woodpecker indexable

Last modified: September 29, 2023

Carl Duguay - [email protected]

Carl is a Victoria-based furniture maker and the web editor at Canadian Woodworking & Home Improvement.

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