In my recent article about Precision rulers, I spent some time extolling the virtues of decent rules in the workshop and the same sentiments can be used when discussing squares as they take an equal amount of abuse. It has to be said though, that they’ve never been used to ‘accidentally’ open an old tin of varnish.

The squares I’ve been using for the last few years were bought from Axminster a long time ago and have seen their fair share of action. My go-to, every day square has a blade length of 150mm and I’ve also got a much larger 300mm one for the big jobs. Thus far, they’ve been fine, notwithstanding that instead of opening varnish tins, the smaller one had become encrusted with glue, gunk and other workshop unmentionables as well as having been dropped on the floor a few times. Suffice to say that when I checked it with a new Precision Engineer’s Square, it’s sadly no longer a true 90° and so, reluctantly, it’s time for it to take up a new residence in the local landfill.

Squares are as important to a furniture maker as fingers. Not much is going to happen if you don’t have either and both have to be accurate and fully functioning. Knowing that my old and trusted square was shortly to be deposed, I’m trying out a few sizes of the new Precision squares which include a couple from the Engineer’s range.

It’s a little known snippet of information, but the traditional carpenter’s square was only ever 90° on the inside only; it was always a bit hit and miss as to whether the outside corner was going to be true. In point of fact, the carpenter, joiner or furniture maker needs both the inside and the outside to be square; there’s little point in marking across a board if it’s not a cast iron certainty that what’s being marked is accurate, so it’s reassuring to know that the new range of Precision Rosewood squares are accurate on both the interior and exterior corners.

What’s more, they’ve been manufactured to BS 3322 and have been tested to a tolerance of less than 0.01mm per 10mm blade length, both inside and outside. Blades are rustproof stainless steel with a matt chrome finish. Each edge has a photo etched, EEC Class 1 scale and the measurements on it are accurate to ±0.05mm over a distance of 300mm. Again, this is the same degree of accuracy as used on some of the new range of tape measures recently introduced.

The new squares comprise an ‘H’ section brass stock, infilled with rosewood.

It’s secured to the blade with three highly polished brass rivets, the combination of which makes for quite a weighty little beast. The 225mm square tips the scales at a respectable 450g or nearly 1lb 2oz in old money. Provided they’re looked after and not used as an emergency hammer to drive in a few brads, these new squares should last a lifetime and beyond.

Many woodworkers prefer to use an engineer’s square as, unlike the traditional carpenter’s square, they’re 90° on all four angles: internal, external, outside blade to inside stock and inside blade to outside stock, but without a recognised grade, there’s no way of being sure of the accuracy. Fortunately, my old go-to 150mm square was reasonably accurate (or as accurate as I needed it to be) when it was new many years ago.

An engineer’s square also has a small machined notch in the inside corner, which is a great aid to accuracy as it allows for any irregularities in the edge of the material being checked. Without the notch, if there’s a slight whisker or a small amount of material overhanging on the edge being checked, it will get trapped and compressed into the corner and affect how the square is sighted.

The new Precision engineer’s squares are a quantum step up in accuracy, as each conforms to Din 875 Grade II (or 2) which is the normal standard for a decent workshop square. Even better, Din 875 Grade II is written large and bold on each stainless steel blade, so the user should have full confidence in its accuracy.

A grade 2 square has always been recognised as being quite sufficient for normal workshop use and if it does inadvertently get dropped onto the floor, it won’t cause a financial meltdown if it needs to be replaced. However, if it does need to be checked, then it should always be done using an Inspection Grade square (normally 1 or better, or its equivalent) and, as a matter of course, this square should never, ever be used in the workshop; instead it ought to be tucked away somewhere warm and cosy aside from the normal melee.

Having replaced my old squares and rules, I will now have absolutely no excuses to offer for any marking out and measuring mistakes on future projects, but as we all know, theory is one thing, practice is quite another.

Watch this space.

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