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Combination square set
maintenance and care

Shop for Protractor Sets


Combination square set storage case; square head, centre head, protractor head, rule, ruler, blade When purchasing your combination square set, you may find that it is supplied in a box or case in which it can be kept when not being used.

Checking for accuracy

A green tick and red cross Over time, it is possible that the combination square set will become inaccurate.
Parallel lines (left) vs. non parallel lines (right); combination square, rule, ruler, blade This may occur if there is a problem with the heads or rule.
Drawing a line with a combination square to test for accuracy It is possible to test whether the square head/rule combination is inaccurate by attaching the square head to the rule and drawing a line from a straight edge.
Checking to see whether the line matches up with the rule; combination square set, square head, ruler, blade Flip the tool over and check whether the rule lines up exactly with the line you just drew. When drawing a second line, it should be parallel to the first.
Parallel lines (left) vs non parallel lines (right); combination square set, square head, rule, ruler, blade If this is not the case, then your rule or square head is likely not accurate.
The slot on the square head into which the rule goes; combination square set, square head, ruler, blade Inside the head you may find two little “pin-like” segments which the rule normally stays level with. If there is wear on the inside of the heads, the rule may sit at an angle.


Filing the "pins" inside the square head; combination square head, file It may be possible to use a file to bring the rule back into line, taping the sides of the file to avoid filing the sides of the head. However, doing this may not be particularly precise, and some advise buying a new tool.
A warranty seal Some manufacturers may simply replace the defective tool providing that it is still guaranteed under warranty and has not been mistreated.
A try square on a surface with damage and debris

What else could cause the combination square set to fail?

The combination square set may also fail if there is debris on or if there has been damage to the work surface.