Why do all rolls have a round hole?

On the steel ruler (tape measure) it turns out there are many features designed to make measurement easier.

You guys are no stranger to rollers - or steel rulers as many people often call right? It is a type of construction made of steel or alloy, capable of being extended by internal springs and mainly used in construction.

Picture 1 of Why do all rolls have a round hole?

However, using a tape measure is not merely a pull-out and measure, because then we can use the normal tape measure as well. On a tape measure there are quite a number of features designed to make measurement easier without us knowing.

The first is the mysterious hole on the head . Each roll has a fold on the top of the ruler, which is used to hook the edge of the table. But that mysterious hole, what do you think it's for?

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What is this hole for?

And the answer is here.

This hole is used to hook into a nail cap, in case you have to measure a fairly long section without anyone helping to keep the other end.

Next, notice that the tape end is designed with small serrated grooves . Why not make flat for beauty? That's because when you're done measuring, you'll need something to mark like a pencil. And if there is no pencil, that jagged area will be an extremely effective and fast marker.

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Not all. Keep looking at the top of the ruler, you will see that the steel attached to the ruler is somewhat loose. Could it be a design error? No, there's a purpose.

In fact, the first inch and the second inch on the steel ruler are not equal, but are 1/16 inches apart. And you know, that "loose" range is about 1/16 of an inch. That is why we can measure accurately with very few errors.

Finally, look at the back of the case, you will see the "cryptic" numbers as follows.

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These numbers are the length of the shell . Usually the left side is in inches, and the right number is in mm. Knowing this number will help you measure objects vertically without suffering as shown below.

Picture 5 of Why do all rolls have a round hole? How much is this?

Instead, you can confidently measure like this!

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