Starrett Combination Square Insert User Manual

Applications: Combination Square Center Head

Applications: Combination Square Protractor Head

Tips for Using Squares and Center Heads

• Ensure that the square is clean and located against a flat surface – irregularities
such as burrs on metal or knots on wood adversely effect accuracy.

• While the steel scriber can be used on any material, it is most commonly used for
metal. A carpenter's pencil is normally used on wood, but a light cut with a utility
knife will produce a finer line, and is also useful for cross grain scribing.

• When using a center head on a piece that may not be completely round, scribe more
than two intersecting lines to achieve the best possible accuracy.

The Starrett Combination Square

Introduction, Assembly & Applications

Congratulations on your purchase of a Starrett
Combinaton Square. Starrett was the first and is still the
best combination square available.

Invented by our Laroy S. Starrett, in 1877, the
combination square was literally the driving force in the
founding of The L.S. Starrett Company in 1880.

After more than 130 years, this practical and versatile tool
is still commonly utilized in a wide variety of applications.

Description and Components

The combination square includes a hardened steel
graduated rule and movable combination square and miter head with spirit level
and scriber. The square head has a precision ground 90° square face and a 45°
miter face. It is a highly versatile layout tool for scribing right angles and parallel
lines, and a measuring tool that can be used as a tri-square, miter, depth gage,
height gage, and level.

The Center Head is an available attachment that provides an easy means of
accurately locating the center of cylindrical or square work.

The Protractor Head is another available attachment. It has revolving turrets with
direct-reading double graduations, a full 0 to 180° in opposite directions. This
permits accurate and quick direct reading of angles above or below the blade.

Complete Sets are available including the rule and all three heads in a fitted case.

Scriber

Spirit Level

Square Head

Lock Bolt

Spirit Level (Reverse Side)

Lock Bolt

Direct Reading Scale

Center Head

Laroy S. Starrett

(1836-1922)

Lock Bolt

Form 955 20M/S 01/10 Specifications subject to change.

starrett.com • 978-249-3551

Steel Rule

Protractor Head

Assembling and Reconfiguring Your Combination Square

This tool was designed as a square that would move up and down a ruler blade
with precision, thus allowing a wide range of applications. The tool consists of a
blade with a machined groove on the center of one side and a square head with a
lockable assembly and specially designed bolt to engage the slot.

• When installing the blade into the head,

be sure to align the bolt with the groove.

• Look at the machined slot on the head

and note the position of the bolt.

• If the bolt is in the wrong position,

loosen the spring loaded lock nut, press
down and turn the post until the bolt
aligns with the blade slot, slide the
blade into the head and lock the nut.

• Follow the same procedure to attach

center and protractor heads.

• The blade has two or four graduation

types along its edges. To reverse the
blade and see different graduations,
loosen the nut, remove the blade, rotate
the bolt 180°, flip and re-insert the
blade, then lock the nut.

Complete Combination Square Set includes
Blade/Rule, Square Head, Center Head,
Protractor Head & Case

Applications: Combination Square with Rule & Movable Head

With 289C Clamp

Block & Scribe