Component Component |
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Manufacturer Model Number Manufacturer Model Number |
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DFARS (Defense Acquisition Regulations Supplement) DFARS (Defense AcquisitionRegulations Supplement) |
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Specifications Met Specifications Met |
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Starrett High-Accuracy Combination Squares
Replace your try square, miter square, depth gauge, height gauge, center-point finder, and level. The blade on these squares meets Fed. Spec. GGG-R-791H, which establishes uniform standards for accuracy, graduations, and size. Blades are labeled with numeric increments that are less than 1" for quick reading. All have wear-resistant etched markings.
Square head checks 90° angles. Center head identifies the center on pipes, rods, and shafts. Protractor head measures angles.
Satin-chrome blade finish is corrosion resistant and reduces glare. Hardened-steel heads are more durable and last longer than cast iron heads.


Blade | Graduation | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Blade Lg. | Front Grad. Marks (Increments) | Back Grad. Marks (Increments) | Accuracy | Wd. | Thick. | Material | Color | Color | Mark Style | Head Lg. | Each | |
Cast Iron Head | ||||||||||||
Inch | ||||||||||||
4" | 32nds (4/32"), 64ths (8/64") | 8ths (1"), 16ths (1") | -0.002" to +0.004" | 5/8" | 1/16" | Satin-Chrome Steel | Silver | Black | Etched | 2 1/4" | 0000000 | 0000000 |
Hardened Steel Head | ||||||||||||
Inch | ||||||||||||
4" | 32nds (4/32"), 64ths (8/64") | 8ths (1"), 16ths (1") | -0.002" to +0.004" | 5/8" | 1/16" | Satin-Chrome Steel | Silver | Black | Etched | 2 1/4" | 0000000 | 000000 |
Replacement Lockbolt for Square and Center Heads | 0000000 | Each | 000000 |


Blade | Graduation | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Blade Lg. | Front Grad. Marks (Increments) | Back Grad. Marks (Increments) | Accuracy | Wd. | Thick. | Material | Color | Color | Mark Style | Head Lg. | Each | |
Cast Iron Heads | ||||||||||||
Inch | ||||||||||||
4" | 32nds (4/32"), 64ths (8/64") | 8ths (1"), 16ths (1") | -0.002" to +0.004" | 5/8" | 1/16" | Satin-Chrome Steel | Silver | Black | Etched | 2 1/4" | 0000000 | 0000000 |
Hardened Steel Heads | ||||||||||||
Inch | ||||||||||||
4" | 32nds (4/32"), 64ths (8/64") | 8ths (1"), 16ths (1") | -0.002" to +0.004" | 5/8" | 1/16" | Satin-Chrome Steel | Silver | Black | Etched | 2 1/4" | 0000000 | 000000 |
Replacement Lockbolt for Square and Center Heads | 0000000 | Each | 000000 |



Blade | Graduation | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Blade Lg. | Front Grad. Marks (Increments) | Back Grad. Marks (Increments) | Accuracy | Wd. | Thick. | Material | Color | Color | Mark Style | Head Lg. | Each | |
Cast Iron Head | ||||||||||||
Inch | ||||||||||||
6" | 32nds (4/32"), 64ths (8/64") | 8ths (1"), 16ths (1") | -0.002" to +0.004" | 3/4" | 5/64" | Steel | Silver | Black | Etched | 2 13/32" | 0000000 | 000000 |
6" | 32nds (4/32"), 64ths (8/64") | 8ths (1"), 16ths (1") | -0.002" to +0.004" | 3/4" | 5/64" | Satin-Chrome Steel | Silver | Black | Etched | 2 13/32" | 0000000 | 000000 |
6" | 32nds (4/32"), 64ths (8/64") | 50ths (1/10"), 100ths (1/10") | -0.002" to +0.004" | 3/4" | 5/64" | Satin-Chrome Steel | Silver | Black | Etched | 2 13/32" | 0000000 | 000000 |
12" | 32nds (4/32"), 64ths (8/64") | 8ths (1"), 16ths (1") | -0.0035" to +0.005" | 1" | 3/32" | Steel | Silver | Black | Etched | 4 1/2" | 0000000 | 00000 |
12" | 32nds (4/32"), 64ths (8/64") | 8ths (1"), 16ths (1") | -0.0035" to +0.005" | 1" | 3/32" | Satin-Chrome Steel | Silver | Black | Etched | 4 1/2" | 0000000 | 000000 |
12" | 32nds (4/32"), 64ths (8/64") | 50ths (1/10"), 100ths (1/10") | -0.0035" to +0.005" | 1" | 3/32" | Satin-Chrome Steel | Silver | Black | Etched | 4 1/2" | 0000000 | 000000 |
18" | 32nds (4/32"), 64ths (8/64") | 8ths (1"), 16ths (1") | -0.0035" to +0.006" | 1" | 3/32" | Satin-Chrome Steel | Silver | Black | Etched | 4 1/2" | 0000000 | 000000 |
24" | 32nds (4/32"), 64ths (8/64") | 8ths (1"), 16ths (1") | -0.0035" to +0.007" | 1" | 3/32" | Satin-Chrome Steel | Silver | Black | Etched | 4 1/2" | 0000000 | 000000 |
Inch/Metric | ||||||||||||
11 3/4"/300mm | 1/2 mm (10 mm), 32nds (4/32") | Millimeters (10 mm), 64ths (8/64") | -0.0035" to +0.005"/ -0.09 mm to +0.15 mm | 1" | 3/32" | Satin-Chrome Steel | Silver | Black | Etched | 4 1/2" | 0000000 | 000000 |
23 1/2"/600mm | 1/2 mm (10 mm), 32nds (4/32") | Millimeters (10 mm), 64ths (8/64") | -0.0035" to +0.007"/ -0.11 mm to +0.25 mm | 1" | 3/32" | Satin-Chrome Steel | Silver | Black | Etched | 4 1/2" | 0000000 | 000000 |
Hardened Steel Head | ||||||||||||
Inch | ||||||||||||
6" | 32nds (4/32"), 64ths (8/64") | 8ths (1"), 16ths (1") | -0.002" to +0.004" | 3/4" | 5/64" | Satin-Chrome Steel | Silver | Black | Etched | 2 13/32" | 0000000 | 000000 |
6" | 32nds (4/32"), 64ths (8/64") | 50ths (1/10"), 100ths (1/10") | -0.002" to +0.004" | 3/4" | 5/64" | Satin-Chrome Steel | Silver | Black | Etched | 2 13/32" | 0000000 | 000000 |
12" | 32nds (4/32"), 64ths (8/64") | 8ths (1"), 16ths (1") | -0.0035" to +0.005" | 1" | 3/32" | Satin-Chrome Steel | Silver | Black | Etched | 3 5/8" | 0000000 | 000000 |
12" | 32nds (4/32"), 64ths (8/64") | 50ths (1/10"), 100ths (1/10") | -0.0035" to +0.005" | 1" | 3/32" | Satin-Chrome Steel | Silver | Black | Etched | 3 5/8" | 0000000 | 000000 |
18" | 32nds (4/32"), 64ths (8/64") | 8ths (1"), 16ths (1") | -0.0035" to +0.006" | 1" | 3/32" | Satin-Chrome Steel | Silver | Black | Etched | 3 5/8" | 0000000 | 000000 |
24" | 32nds (4/32"), 64ths (8/64") | 8ths (1"), 16ths (1") | -0.0035" to +0.007" | 1" | 3/32" | Satin-Chrome Steel | Silver | Black | Etched | 3 5/8" | 0000000 | 000000 |
24" | 32nds (4/32"), 64ths (8/64") | 50ths (1/10"), 100ths (1/10") | -0.0035" to +0.007" | 1" | 3/32" | Satin-Chrome Steel | Silver | Black | Etched | 3 5/8" | 0000000 | 000000 |
Inch/Metric | ||||||||||||
11 3/4"/300mm | 1/2 mm (10 mm), 32nds (4/32") | Millimeters (10 mm), 64ths (8/64") | -0.0035" to +0.005"/ -0.09 mm to +0.15 mm | 1" | 3/32" | Satin-Chrome Steel | Silver | Black | Etched | 3 5/8" | 0000000 | 000000 |
23 1/2"/600mm | 1/2 mm (10 mm), 32nds (4/32") | Millimeters (10 mm), 64ths (8/64") | -0.0035" to +0.007"/ -0.11 mm to +0.25 mm | 1" | 3/32" | Satin-Chrome Steel | Silver | Black | Etched | 3 5/8" | 0000000 | 000000 |


Blade | Graduation | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Blade Lg. | Front Grad. Marks (Increments) | Back Grad. Marks (Increments) | Accuracy | Wd. | Thick. | Material | Color | Color | Mark Style | Head Lg. | Each | |
Cast Iron Heads | ||||||||||||
Inch | ||||||||||||
6" | 32nds (4/32"), 64ths (8/64") | 8ths (1"), 16ths (1") | -0.002" to +0.004" | 3/4" | 5/64" | Satin-Chrome Steel | Silver | Black | Etched | 2 13/32" | 0000000 | 0000000 |
12" | 32nds (4/32"), 64ths (8/64") | 8ths (1"), 16ths (1") | -0.0035" to +0.005" | 1" | 3/32" | Satin-Chrome Steel | Silver | Black | Etched | 4 1/2" | 0000000 | 000000 |
12" | 32nds (4/32"), 64ths (8/64") | 50ths (1/10"), 100ths (1/10") | -0.0035" to +0.005" | 1" | 3/32" | Satin-Chrome Steel | Silver | Black | Etched | 4 1/2" | 0000000 | 000000 |
18" | 32nds (4/32"), 64ths (8/64") | 8ths (1"), 16ths (1") | -0.0035" to +0.006" | 1" | 3/32" | Satin-Chrome Steel | Silver | Black | Etched | 4 1/2" | 0000000 | 000000 |
24" | 32nds (4/32"), 64ths (8/64") | 8ths (1"), 16ths (1") | -0.0035" to +0.007" | 1" | 3/32" | Satin-Chrome Steel | Silver | Black | Etched | 4 1/2" | 0000000 | 000000 |
Hardened Steel Heads | ||||||||||||
Inch | ||||||||||||
6" | 32nds (4/32"), 64ths (8/64") | 8ths (1"), 16ths (1") | -0.002" to +0.004" | 3/4" | 5/64" | Satin-Chrome Steel | Silver | Black | Etched | 2 13/32" | 0000000 | 000000 |
12" | 32nds (4/32"), 64ths (8/64") | 8ths (1"), 16ths (1") | -0.0035" to +0.005" | 1" | 3/32" | Satin-Chrome Steel | Silver | Black | Etched | 3 5/8" | 0000000 | 000000 |
12" | 32nds (4/32"), 64ths (8/64") | 50ths (1/10"), 100ths (1/10") | -0.0035" to +0.005" | 1" | 3/32" | Satin-Chrome Steel | Silver | Black | Etched | 3 5/8" | 0000000 | 000000 |
18" | 32nds (4/32"), 64ths (8/64") | 8ths (1"), 16ths (1") | -0.0035" to +0.006" | 1" | 3/32" | Satin-Chrome Steel | Silver | Black | Etched | 3 5/8" | 0000000 | 000000 |
24" | 32nds (4/32"), 64ths (8/64") | 8ths (1"), 16ths (1") | -0.0035" to +0.007" | 1" | 3/32" | Satin-Chrome Steel | Silver | Black | Etched | 3 5/8" | 0000000 | 000000 |


Blade | Graduation | Cast Iron Heads | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Blade Lg. | Front Grad. Marks (Increments) | Back Grad. Marks (Increments) | Accuracy | Wd. | Thick. | Material | Color | Color | Mark Style | Head Lg. | Each | |
Inch | ||||||||||||
12" | 32nds (4/32"), 64ths (8/64") | 8ths (1"), 16ths (1") | -0.0035" to +0.005" | 1" | 3/32" | Steel | Silver | Black | Etched | 4 1/2" | 0000000 | 0000000 |
18" | 32nds (4/32"), 64ths (8/64") | 8ths (1"), 16ths (1") | -0.0035" to +0.006" | 1" | 3/32" | Steel | Silver | Black | Etched | 4 1/2" | 0000000 | 000000 |
24" | 32nds (4/32"), 64ths (8/64") | 8ths (1"), 16ths (1") | -0.0035" to +0.007" | 1" | 3/32" | Steel | Silver | Black | Etched | 4 1/2" | 0000000 | 000000 |
Replacement Lockbolt for Square, Center, and Protractor Heads | 0000000 | Each | 00000 |
![]() | ![]() Inch |
![]() Inch/Metric |
Blade | Graduation | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Blade Lg. | Front Grad. Marks (Increments) | Back Grad. Marks (Increments) | Accuracy | Wd. | Thick. | Material | Color | Color | Mark Style | Head Lg. | Each | |
Cast Iron Heads | ||||||||||||
Inch | ||||||||||||
12" | 32nds (4/32"), 64ths (8/64") | 8ths (1"), 16ths (1") | -0.0035" to +0.005" | 1" | 3/32" | Steel | Silver | Black | Etched | 4 1/2" | 0000000 | 0000000 |
12" | 32nds (4/32"), 64ths (8/64") | 50ths (1/10"), 100ths (1/10") | -0.0035" to +0.005" | 1" | 3/32" | Steel | Silver | Black | Etched | 4 1/2" | 0000000 | 000000 |
18" | 32nds (4/32"), 64ths (8/64") | 8ths (1"), 16ths (1") | -0.0035" to +0.006" | 1" | 3/32" | Steel | Silver | Black | Etched | 4 1/2" | 0000000 | 000000 |
24" | 32nds (4/32"), 64ths (8/64") | 8ths (1"), 16ths (1") | -0.0035" to +0.007" | 1" | 3/32" | Steel | Silver | Black | Etched | 4 1/2" | 0000000 | 000000 |
Inch/Metric | ||||||||||||
11 3/4"/300mm | 1/2 mm (10 mm), 32nds (4/32") | Millimeters (10 mm), 64ths (8/64") | -0.0035" to +0.005"/-0.09 mm to +0.15 mm | 1" | 3/32" | Steel | Silver | Black | Etched | 4 1/2" | 0000000 | 000000 |
23 1/2"/600mm | 1/2 mm (10 mm), 32nds (4/32") | Millimeters (10 mm), 64ths (8/64") | -0.0035" to +0.007"/-0.11 mm to +0.25 mm | 1" | 3/32" | Steel | Silver | Black | Etched | 4 1/2" | 0000000 | 000000 |
Hardened Steel Heads | ||||||||||||
Inch | ||||||||||||
12" | 32nds (4/32"), 64ths (8/64") | 8ths (1"), 16ths (1") | -0.0035" to +0.005" | 1" | 3/32" | Satin-Chrome Steel | Silver | Black | Etched | 3 5/8" | 0000000 | 000000 |
12" | 32nds (4/32"), 64ths (8/64") | 50ths (1/10"), 100ths (1/10") | -0.0035" to +0.005" | 1" | 3/32" | Satin-Chrome Steel | Silver | Black | Etched | 3 5/8" | 0000000 | 000000 |
18" | 32nds (4/32"), 64ths (8/64") | 8ths (1"), 16ths (1") | -0.0035" to +0.006" | 1" | 3/32" | Satin-Chrome Steel | Silver | Black | Etched | 3 5/8" | 0000000 | 000000 |
18" | 32nds (4/32"), 64ths (8/64") | 50ths (1/10"), 100ths (1/10") | -0.0035" to +0.006" | 1" | 3/32" | Satin-Chrome Steel | Silver | Black | Etched | 3 5/8" | 0000000 | 000000 |
24" | 32nds (4/32"), 64ths (8/64") | 8ths (1"), 16ths (1") | -0.0035" to +0.007" | 1" | 3/32" | Satin-Chrome Steel | Silver | Black | Etched | 3 5/8" | 0000000 | 000000 |
24" | 32nds (4/32"), 64ths (8/64") | 50ths (1/10"), 100ths (1/10") | -0.0035" to +0.007" | 1" | 3/32" | Satin-Chrome Steel | Silver | Black | Etched | 3 5/8" | 0000000 | 000000 |
Inch/Metric | ||||||||||||
11 3/4"/300mm | 1/2 mm (10 mm), 32nds (4/32") | Millimeters (10 mm), 64ths (8/64") | -0.0035" to +0.005"/-0.09 mm to +0.15 mm | 1" | 3/32" | Satin-Chrome Steel | Silver | Black | Etched | 3 5/8" | 0000000 | 000000 |
23 1/2"/600mm | 1/2 mm (10 mm), 32nds (4/32") | Millimeters (10 mm), 64ths (8/64") | -0.0035" to +0.007"/-0.11 mm to +0.25 mm | 1" | 3/32" | Satin-Chrome Steel | Silver | Black | Etched | 3 5/8" | 0000000 | 000000 |
Replacement Lockbolt for Square, Center, and Protractor Heads | 0000000 | Each | 00000 |
Starrett High-Accuracy Combination Square Blades


Use these blades with Starrett High-Accuracy Combination Square Heads. They meet Fed. Spec. GGG-R-791H, which establishes uniform standards for accuracy, graduations, and size. Blades are labeled with numeric increments that are less than 1" for quick reading. All have wear-resistant etched markings.
Satin-chrome finish is corrosion resistant and reduces glare.
Graduation | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|
Lg. | Front Graduation Marks (Numeric Increments) | Back Graduation Marks (Numeric Increments) | Accuracy | Wd. | Thick. | Color | Color | Mark Style | Each | |
Inch | ||||||||||
Satin-Chrome Steel | ||||||||||
4" | 32nds (4/32"), 64ths (8/64") | 8ths (1"), 16ths (1") | -0.002" to +0.004" | 5/8" | 1/16" | Silver | Black | Etched | 0000000 | 000000 |
4" | 32nds (4/32"), 64ths (8/64") | 50ths (1/10"), 100ths (1/10") | -0.002" to +0.004" | 5/8" | 1/16" | Silver | Black | Etched | 0000000 | 00000 |
6" | 32nds (4/32"), 64ths (8/64") | 8ths (1"), 16ths (1") | -0.002" to +0.004" | 3/4" | 5/64" | Silver | Black | Etched | 0000000 | 00000 |
6" | 32nds (4/32"), 64ths (8/64") | 50ths (1/10"), 100ths (1/10") | -0.002" to +0.004" | 3/4" | 5/64" | Silver | Black | Etched | 0000000 | 00000 |
12" | 32nds (4/32"), 64ths (8/64") | 8ths (1"), 16ths (1") | -0.0035" to +0.005" | 1" | 3/32" | Silver | Black | Etched | 0000000 | 00000 |
12" | 32nds (4/32"), 64ths (8/64") | 50ths (1/10"), 100ths (1/10") | -0.0035" to +0.005" | 1" | 3/32" | Silver | Black | Etched | 0000000 | 00000 |
24" | 32nds (4/32"), 64ths (8/64") | 8ths (1"), 16ths (1") | -0.0035" to +0.007" | 1" | 3/32" | Silver | Black | Etched | 0000000 | 000000 |
24" | 32nds (4/32"), 64ths (8/64") | 50ths (1/10"), 100ths (1/10") | -0.0035" to +0.007" | 1" | 3/32" | Silver | Black | Etched | 0000000 | 000000 |
36" | 32nds (4/32"), 64ths (8/64") | 8ths (1"), 16ths (1") | -0.0035" to +0.007" | 1" | 3/32" | Silver | Black | Etched | 0000000 | 000000 |
Inch/Metric | ||||||||||
Satin-Chrome Steel | ||||||||||
11 3/4"/300mm | 1/2 mm (10 mm), 32nds (4/32") | Millimeters (10 mm), 64ths (8/64") | -0.0035" to +0.005"/-0.09 mm to +0.15 mm | 1" | 3/32" | Silver | Black | Etched | 0000000 | 00000 |
23 1/2"/600mm | 1/2 mm (10 mm), 32nds (4/32") | Millimeters (10 mm), 64ths (8/64") | -0.0035" to +0.007"/-0.11 mm to +0.25 mm | 1" | 3/32" | Silver | Black | Etched | 0000000 | 000000 |
Starrett High-Accuracy Combination Square Heads
Attach to Starrett High-Accuracy Combination Square Blades with the included lockbolts.
Square head checks 90° angles. Center head identifies the center on pipes, rods, and shafts. Protractor head measures angles.
Hardened-steel heads are more durable and last longer than cast iron heads.



Protractor | |||||
---|---|---|---|---|---|
Component | For Blade Lgs. | Angle Measuring Range | Graduation Marks (Numeric Increments) | Each | |
Cast Iron | |||||
Square Head | 4" | __ | __ | 0000000 | 000000 |
Square Head with Built-in Level | 6" | __ | __ | 0000000 | 00000 |
Square Head with Built-in Level | 12"-48" | __ | __ | 0000000 | 00000 |
Center Head | 4" | __ | __ | 0000000 | 00000 |
Center Head | 6" | __ | __ | 0000000 | 00000 |
Center Head | 12"-48" | __ | __ | 0000000 | 00000 |
Nonreversible Protractor Head with Built-in Level | 12"-48" | 0°-180° | 1° (10°) | 0000000 | 000000 |
Reversible Protractor Head with Built-in Level | 12"-48" | 0°-180° | 1° (10°) | 0000000 | 000000 |
Hardened Steel | |||||
Square Head | 4" | __ | __ | 0000000 | 00000 |
Square Head with Built-in Level | 6" | __ | __ | 0000000 | 00000 |
Square Head with Built-in Level | 12"-48" | __ | __ | 0000000 | 00000 |
Center Head | 4" | __ | __ | 0000000 | 00000 |
Center Head | 6" | __ | __ | 0000000 | 000000 |
Center Head | 12"-48" | __ | __ | 0000000 | 00000 |
Starrett High-Accuracy Squares

These squares meet Fed. Spec. GGG-S-656-E, which establishes uniform standards for square accuracy to ensure reliable, repeatable angles.
Blade | ||||||||
---|---|---|---|---|---|---|---|---|
Lg. | Wd. | Thick. | Accuracy | Color | Container | Container Material | Each | |
Inch | ||||||||
Steel | ||||||||
1 1/2" × 1 1/2" | 1/2" × 17/32" | 3/64" × 1/4" | +0.0001" | Silver | Case | Wood | 0000000 | 0000000 |
3" × 2 3/8" | 47/64" × 7/8" | 1/16" × 13/32" | +0.0001" | Silver | Case | Wood | 0000000 | 000000 |
4 1/2" × 3 1/2" | 1 1/8" × 15/16" | 23/32" × 1/2" | +0.0001" | Silver | Case | Wood | 0000000 | 000000 |
6" × 4 5/16" | 1 5/16" × 1 1/16" | 5/64" × 1/2" | +0.0001" | Silver | Case | Wood | 0000000 | 000000 |
12" × 7" | 2" × 1 31/64" | 5/64" × 3/4" | +0.0002" | Silver | Case | Wood | 0000000 | 000000 |