What is a Combination Square

How to use a combination square set

What is a combination squareWhat is a combination square? The composition of the Combination Square consists of ruler blade on to it various head can slid along its length.


Uses of a combination square:

The basic head is one that has a 90 degree face and a 45 degree face these are used to check or lay out right and 45 degree angles.

There are other heads and one very common one is a centre finder of round material.

What is a Combination Square used for:

  • First to create a reference surface on the material to work from, the surface must be flat. Using the ruler blade of the Combination set to check for the flatness.
  • Then using the basic head it can work from the reference to create right angled areas from it.
  • Using the 45 degree angle create miter joints.
  • Using the centre finder of a round workpiece the two cast iron legs of the centre finder with the ruler blade resting on the round surface aline is scribed across it.
  • Then moving the centre finder to another position and scribing again, where the two lines cross is the centre.
  • The basic head can be used as a depth gauge, resting the 90 degree on the material and moving the ruler blade down the depth can be determined.
  • Then using the locking screw this measurement can be transferred to another article to ensure it is cut to the same dimension.

Please note:
If viewing from Canada, France or United Kingdom articles selected to view may be substituted for an equivalent model if the selected model is not available in your country.


Empire Level E250 12-Inch Heavy Duty Professional Combination Square w/Etched Stainless Steel Blade and True BlueR Vial


  • The Empire Level is a 12” is a professional heavy duty combination square.
  • The stainless steel blade is etched in inches and has a True Blue vial for accurate levelling.
  • The easy readable vial has a guaranteed accuracy to within 0.0005”.
  • The steel blade has a matte finish and will not corrode or rust being manufactured of stainless steel.
  • The draw bolt is self-aligning lock the heavy duty machined head.
  • A hardened scriber is included for marking materials being worked on.
  • Manufactured in the USA.
  • A 5 year limited warranty.

There are a number of critical reviews that indicate that quality control has not been vigil enough.

The top reviewers considered the product was value for money.


See the latest price of Empire Level here…




IRWIN Tools Combination Square, Metal-Body, 6-Inch (1794468)


  • For durability the Irwin Combination
  • square has a cast zinc body.
  • For rugged use the blade is manufacture from stainless steel.
  • The blade has black etched scales are in inches to give accuracy.
  • The body is in black with two settings 90 and 45 degrees.
  • Included in the head is a highly visible level vial.


The tool can be used as a depth gauge and it can be purchase in three blade lengths 6”, 12” and 16”.


See the latest price of IRWIN Tools Combination Square here…



Kreg KMA2900 Multi-Mark Multi-Purpose Marking and Measuring Tool


  • This is a very handy multi-purpose marking tool.
  • It has a 3/16” reveal gauge and a built in level.
  • There are three scale positions
  • To trim a door there is a 3/16” offset.
  • To transfer measurements there is a cumulative scale.
  • Ideal for general layout.
  • Made in the USA.


This product is a comparative newcomer to the market. It was conceived by the designer in 1986 when he was building his house and installing some kitchen cabinets.

He didn’t want to nail them so came up with the idea of this product to fit the face frames so he could attach them without the fixings wouldn’t show.

So the present product was the development of the original “Craig’s Jig” to the present product now available..
It has a multitude of applications for Jobsite or Household use.


There are a number of criticisms regarding its not being square but if they had looked at the photo it was obvious that there could be some play in the fixing..
Those at the top 5 stars realised and used the product for what it is.


See the latest price of Kreg here…




PEC 12″ 4R 4 piece combination machinist square with reversing protractor marked with 1/32″, 1/64″, 1/8″, 1/16″


The blade of the PEC 12” is hardened and tempered steel and is 1” wide x 085” thick.
It is has a satin chrome finish and precision photo etched filled black foe easy reading.

The main head is manufactured from cast iron, a spirit level is inset in it.
A centre finder is included and manufactured to the same standard.
Also included is a protractor that is reversible and includes a spirit vial.

A hardened steel scriber is included..
The complete assembly is housed in a folded plastic case.

The PEC product is manufactured in the USA.


See the latest price of PEC 12″ here…




Starrett C11HC-12-4R Cast Iron Square Head And Center Head With Satin Chrome Blade Combination Square, Black Wrinkle Finish, 4R Graduation, 12″ Size


The Blade is manufactured of hardened and tempered steel finished in satin chrome..
It is photographically engraved in inches with graduated steps 1/64”..
The combination square heads are manufactured in cast iron and have a black wrinkle finish.

They have accurately ground bearing surfaces..
Also fitted with a spirit level and a reversible lock bolt.
A hardened steel scriber is also included.


Useful tips:

  • When locating against the workpiece remove any burs or debris.
  • The square must be clean to go against a flat surface.
  • The scriber can be used to mark the material but on wood a carpenter’s pencil or a utility knife is used.
  • The knife give a finer mark and is very good when marking cross grain.


See the latest price of Starrett C11HC-12-4R here…





What is a Combination Square – Recommendation


The best combination square set is the Sterratt Combination Square is considered in the trade to be the best unit available. Invented in 1877 and the Starrett Company was formed in 1880 and has stood the test of time.


If your need for a combination square is limited and you consider the cost of the Starrett can not be justified.


Then consider then either the: Empire Level E250 12-Inch Heavy Duty Professional Combination Square w/Etched Stainless Steel Blade and True BlueR Vial or IRWIN Tools Combination Square, Metal-Body, 6-Inch