Combination Square Operation Manual

Combination square is an essential tool for carpenters, machinists and builders. It is a convenient blend of a ruler and a right-angled headstock. Hence, this marking tool boosts measurements for both length and angles. Starrett combination square set eases tasks like marking cut lines, checking right angles and measuring depths.
For instance, woodworking helps craftsmen create precise joinery, while metalworkers rely on it for accurate measurements during fabrication. This tool combines the features of a ruler and a protractor to make accurate measurements.

What Angles Can the Square Head Mark and Check?

The square head of a combination set is a tool that can mark and check angles of 90° and 45°. It has two measuring faces. One at 90° and another at 45° to the rule.
In addition to measuring angles, the square head can be used for setting workpieces on machines, measuring the depth of slots, ensuring the integrity of a 90° angle, measuring a 45° angle, finding the centre of a circular object, determining depth, making simple distance measurements, and determining level & plumb using its spirit level vial.

Assemble Combination Square in Just 5 Steps

  1. First of all, align the bolt with the groove when putting the blade into the head.
  2. If the bolt is not in the right place, loosen the spring-loaded lock nut.
  3. Then, press down and turn the post until the bolt aligns with the blade slot.
  4. Finally, slide the blade into the head and secure it by locking the nut.
  5. Repeat the same steps for attaching square and protractor heads.

Also, the blade has two or four graduations along its edges. So, to switch and view different graduations:

  • Loosen the nut and remove the blade.
  • Rotate the bolt 180°, flip and re-insert the blade, then lock the nut.

How to Use Combination Square?

To use a combination square, adjust the blade to the desired angle or length by loosening the locking mechanism and sliding it along the ruler. Once set, tighten the locking mechanism to secure the blade. Then, place the square against the edge of the material to be measured or marked, ensuring the blade is flush against it. You can also use a ruler to make precise measurements or draw straight lines. It’s important to double-check measurements for accuracy before marking or cutting. After use, make sure to clean the combination square and store it in a safe place for future use.

With the Square Head

  • First, ensure that the combination square is clean and in good condition.
  • Tighten any locking screws to secure the square head in the desired position along the blade.
  • Next, clamp the material on a flat and stable surface.
  • Place the combination square against the edge of the material where you need to make a mark.
  • Then, align the square head precisely with the edge of the material.
  • Also, ensure that the combination square is firmly held in place.
  • At last, use the included scriber to make a clear and precise mark along the edge of the square head.

With the Protractor Head

  • If you need to mark an angle, first loosen the locking screw on the protractor head.
  • Then, set the protractor head to the desired angle by aligning it with the markings on the ruler.
  • Keep the material securely in place on your work surface.
  • Next, position the combination square with the protractor head against the material, aligning the blade with the reference edge.
  • Ensure that the combination square is stable and well-supported.
  • Now, use a pencil or the included scribing tool to make a precise mark at the desired angle.

Pro Tips:

  • Double-check measurements and angles before making any marks to avoid errors.
  • Apply consistent and gentle pressure when making marks to maintain accuracy.
  • Regularly check and calibrate your combination square set to ensure accurate measurements.

But, Why Starrett Combination Square?

Starrett understands that just one configuration can not fulfil all the shop’s needs. One variant may cater to one process, but not all shop needs. That’s why the brand produces combination square sets and accessories in both cast iron and forged steel variants. The cast iron combination square is ideal for woodworking. In contrast, the forged steel combination square is the preferred choice for metalworking applications.

A Starrett combination square is made with world-class features. The rule, for instance, is precision-machined and not painted or stamped. Precision machined marks are impossible to remove. As a result, the markings on Starrett rules will not wear out and will be visible even when you use them aggressively.

Available Starrett Combination Squares

ItemHead LengthHead MaterialSpirit LevelScribe Pin*
C11H-4-4R4″Cast Iron
C11H-6-4R6″Cast IronYesYes
C11H-12-4R12″Cast IronYesYes
C11H-24-4R24″Cast IronYes

*Scribe pins are attached to the back of the square heads and can also be used instead of a pencil for marking.

Moreover, the square heads are available in a black wrinkle finish. This finish provides dexterity and is thus easy to grip.

Starrett protractor heads have angle markings at the front (0 to 180 degrees) and a spirit level at the back. They also have locking holes to lock the blade and angle as well.

How Does the Protractor Benefit Daily Shop Jobs?

You can measure lengths in any direction that is practically possible if you have a set of Starrett squares and protractors.

  • Set the unit to 180 degrees and now you have a plane parallel to the base.
  • Or, set it to 90 degrees and make accurate measurements perpendicular to the base.
  • Also, you can set the protractor to any specific angle for slanting jobs, e.g., drilling slanting holes.

Available Starrett Protractor Heads

CPR-1224SCast IronSmooth Black EnamelReversible*
CPNR-1224WCast IronBlack WinkleNon-Reversible**

*Reversible protractors have measurement scales in both clockwise and counter-clockwise directions.

**Non-reversible protractors have measurement scales in only a clockwise direction.

Say goodbye to measurement inaccuracies. Get Starrett combination square sets and components at Raptor Supplies today!

Who We Are?

Raptor Supplies is an international MRO supplier and an authorised Starrett distributor. We provide the entire range to customers in the UK, Europe, the Middle East and Asia. You can also contact us via phone, WhatsApp or email at any time with our 24×7 chat support.