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Wednesday, 19 October 2011

The Combination Square

many uses for a combination square

Invented in the United States in 1878 the combination square is a very versatile instrument indeed. I thought it might be fun to run through as many ways to use one as I can think of and then see if anyone can come up with any others.

As well as the obvious uses for marking lines square to or at 45 degrees to an edge, the combination square can also be used as a depth gauge:

using a combination square as a depth gauge

A rudimentary marking gauge or panel gauge:

using a combination square as a panel gauge

A protractor, dovetail marker or an extra sliding bevel if need be:

using a combination square as a protractor

A graduated centre finder for both establishing and measuring from the centres of round materials:

using a combination square as a centre finder

Or a mitre gauge:

using a combination square as a mitre gauge

A small level, (and because it's a square you also have a means of gauging for plumb):

using a combination square as a level

A greater level of accuracy can often be achieved by using the components independently.

The square head can be used as an internal 135 and 90 degree square:

using a combination square as an internal square

The centre finder as an external 90 degree square (note the cutout for the corner to rest in):

using a combination square as an external square

And the protractor head can be used as either a level or an inclinometer:

using a combination square as an inclinometer

On a good one like this Starrett C435M-300 Metric Combination Set, the photo engraved hardened steel blade is accurate enough to use as a straight edge too:

using a combination square as a straight edge

In almost all cases a dedicated tool probably will do a better job (assuming that you are looking at a similar quality level). However, for a lot of woodworking tasks the level of accuracy you can achieve with a decent combination square is perfectly acceptable.

If budgetary restrictions are a consideration then you may be better off getting one good quality combination set than struggling with lower quality individual tools.

The sheer abundance of things that you can do with a decent combination square make it a wise investment for the beginner woodworker and it will always be a useful tool to grab whether you are working in or away from the workshop.