Steel rules have, for centuries, been indispensable measurement instruments for the world's architects, designers, construction professionals and more. That's as true today as it was back then despite the advent of advanced precision laser measurement tools. It may be a basic measurement tool but a decent quality steel rule is still a highly accurate piece of kit when used properly.
What is a steel rule?
A steel rule is exactly what it sounds like... a rule manufactured from either spring or stainless steel that feature either metric or imperial (or both) scales along its length. One end is usually flat whilst the other end (frequently including a hole for hanging) is usually round.
Steel rules can come in either flexible or rigid forms and in a variety of thicknesses and lengths. The most commonly purchased lengths are 150mm (15cm), 300mm (30cm), 600mm (60cm) and 1,000mm. However, whilst we might not advertise them all on our website, we can also source professional quality rulers right up to 6m in length.
Measurements or graduations
When considering the metric scale this is usually subdivided into either 1mm graduations or 0.5mm graduations for enhanced precision. The imperial scale, on the other hand, can be subdivided into a whole range of measurements. From 8ths, 16ths, 32nds and 64ths, to 10ths, 20ths, 50ths and 100ths...
With so many different types of steel rulers on offer it's very important to ensure you're choosing the right one. The product page for each rule sold via The Tape Store will include the length and, crucially, the measurements featured. If you have any questions about which rule is most suitable for you please don't hesitate to get in touch.
The rigidity of a rule will depend almost entirely on two factors; the type of the steel used (spring steel or stainless steel) and the thickness of that steel. The thicker the steel the more rigid the rule whilst spring steel rules will generally be more rigid than their stainless equivalents. That said, stainless steel or rustless rules are much more popular on the whole thanks to their resistance to corrosion.
Caring for your steel rule
Solid and rigid it may be but a steel rule is not a scraper, is not a screwdriver and is not designed to be used for anything but taking accurate measurements. Neither is it designed to take abuse such as dropping, banging, abrasion, bending and so on. As with all tools, how it's treated by the user will determine how well it performs and, critically, how long it lasts.
Ideally you should always keep your steel very lightly oiled to avoid corrosion as even less durable forms of stainless steel can see corrosion develop over time. What's more, you should immediately replace your rule as soon as you notice any damage such as damaged corners, dented edges or worn markings.
How to use your rule properly
Providing the edges and corners of your rule are crisp and straight (consider changing your rule if they are not) then you should be OK to measure from the very end of the rule. However, to maintain maximum accuracy, this should only be done when you can butt the end of the rule hard up against a square sold object. Using this method under other circumstances can lead to inaccuracies.
In an ideal world, and to avoid inaccuracies, it is far better to offset your measurement, i.e. to start from a known point. The easiest way to do this is to line up the 1cm or 1" mark with the end of the part or object you are looking to measure. You then simply add that 1cm or 1" back onto the final measurement to achieve the correct reading. Measuring from a graduation should be more accurate than measuring from the end due to the wear that the end can experience and the difficulty of visually linikng things up.
When measuring an object always try to ensure that the full is sitting directly on top of the part/object, perpendicular to the object rather than lying flat on it. The 'parallax' phenomenon (whereby false/inaccurate readings can be taken due to optical illusions) can lead to incorrect readings if the rule is laid flat. The user should also ensure that the object they are measuring is perfectly flat by checking for light passing between the rule and the object.