Ross 300Mm Combination Square – Precision Measuring Tool

Description

ROSS Combination Square – 300mm

Product Description

 

• A combination square is a multi-use measuring instrument which is primarily used for ensuring the integrity of a 90° angle, measuring a 45° angle.
• Measuring the centre of a circular object, find depth, and simple distance measurements.
• It can also be used to determine level and plumb using its spirit level vial.
• Steel scriber and a steel blade.
• Etched mm graduations.

 

Terminology

 

• Before using a combination square, one must first be familiar with the structure and terminology of the square itself.
• A combination square consists of a rue-type blade attached to a handle.
• The handle is composed of two parts, a shoulder and an anvil.
• The shoulder is placed at an angle of 45° between itself and the blade.
• It is therefore used for the measurement and layout of miters.
• The anvil is placed at a 90° angle between itself and the blade.
• The handle contains an adjustable knob which allows it to move freely horizontally along the edge of the ruler so that it may be tailored towards any size job.
• Additionally, contained within the head of the handle is a scriber used for marking measurements and a vial which may be used for measuring plumb and level.

 

Testing for Accuracy

 

• Regardless of the job being undertaken, the first step when using a combination square is to check the square to ensure its accuracy.
• This task can be easily accomplished by first taping a white piece of paper to a board with a perfectly straight edge.
• Place the anvil of the square against this edge and draw a line on the outside edge of the blade.
• Once this is complete, turn over the square and draw a second line at least 1/32 in, away from the first line drawn.
• If the two lines drawn are parallel with each other, then it can be said that the combination square is accurate.
• To test the accuracy of the shoulder, one may simply gauge the angle it makes with the blade against a 45° drafting triangle.
• If the angle between the shoulder and the blade is the same as that of the triangle, then the square is accurate.

 

How To Use a Combination Square

 

• Place the shoulder of the square against the edge of the working surface you wish to cut.
• Draw a line along the blade edge until your pencil reaches the shoulder of the combination square.
• Once completed, the line should be a perfect 45° angle with the edge of the working surface. 

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