The humble rule is one of those workshop tools most of us take for granted. And I’m no exception.
For many years I’ve used and abused a pair of rather good Rabone Chesterman stainless steel rules. But over the course of a few decades, the wear and tear of workshop use has sadly taken its toll. That said, the rules in the ‘shop have been replaced with a few of the new Axminster Precision range that have been recently introduced.
Advantages to Precision Range
Made from Japanese rust resistant, stainless steel, Axminster Precision rules are finished with an anti-glare, satin chrome. My old RC rules had no such finish and as such were quite awkward to read under bright lighting conditions. This finish is therefore a definite advantage.
Each Precision rule is chemically photo-etched and the markings, including the easy-to-read font, are filled with a tough, black pigment and most are supplied with a convenient hanging hole at one end. The exception to this, is the two hook rules.
Accuracy is key
My old RC rules are accurate to BS 4372 and a couple of extracts from that standard mention that:
‘Maximum permitted departure from nominal for the distance between any two graduation lines on a single scale up to and including 300mm: 0.1mm. Maximum permitted departure from nominal for the position of the 10mm graduation line from its flat end datum: 0.08mm.’
Axminster Precision rules conform to EEC Class 1 Standard (also used for some of our new tape measures). This states that over a 2m length, there should be a tolerance of ±0.3mm. If my sums are correct, they’re accurate to ±0.05mm over 300mm.
Looking at standards is confusing at the best of times, but EEC Class 1 accuracy is without doubt excellent for all normal workshop measuring activities. Comparing my old 300mm CR rule against the Precision Hook Rule, it can be seen that for all practical purposes, there’s no discernible difference between the two.
For any users who want to know the precise accuracy of their own new Precision Rule, the top of the range Signature rules provide the answer. Each individual rule is accompanied by its own unique calibration certificate. On my particular rule, the top side 0-300mm measurement is actually 300.120mm, an error of 0.04%.
A rule for all uses
Two unique rules already discussed are the new Hook Rules where an adjustable stainless steel hook is provided at one end.
Measuring accurately from an edge is usually always a fraught experience. There’s a possibility of error because it’s difficult to line up the end of the rule, and the edge of the material. It can be done by using a square. However, this you need to use two tools instead of one. The hook rule circumvents that quite neatly.
Two other unusual rules that are well worth having are the Centre Finding Rules.
Sometimes it’s very useful to be able to work outwards from the centre point. You can see this is the picture below.
It shows the current job in the ‘shop, chest of drawers in oak and English walnut for my wife. The drawers have been fitted and the centre line (arrowed) has been drawn down the middle of each. To fit a pair of handles to each drawer, the Centre Finding Rule could be used to mark the position of a pair of lines, one on each side.
Although not strictly a rule, the last Precision tool to mention is the new D head protractor. Having used a much inferior version, this new protractor is simply light years ahead. If you need a protractor, this is unquestionably the one to buy. The only thing missing is a hanging hole in the end!