Sand Hourglass Accuracy

As a sand timer factory, we are constantly asked questions about the accuracy of sand timers. It is a critical factor of the hourglass, so we should write a blog to clarify these questions.

The running time of our sand hourglasses is accurate to +/- 10%. But 10% is the worst situation. The accuracy of our sand timers is much better than that. Last month, a customer did the 15 minutes sand timer inspection before shipping, and the tolerance of all 200 pcs samples is within 20 seconds.

There are some factors to affect the accuracy.

Sand hourglasses with short duration are more accurate than long duration ones. Generally, 30 seconds sand timers are more accurate than 30 minutes ones. It’s not because 30-second ones are of better quality, but just less running time to cause fewer issues.

Hourglasses with large holes are more accurate than ones with small holes. A large hole can ensure the sand flow down more smoothly. That does not mean the sand timer with small holes will get stuck, just more smoothly.

The size of the sand inside the hourglass is not exactly the same, though we can’t tell the difference with your eyes. Every time when you turn over the hourglass, the sand is in a different position. This situation might have a minor influence on the running time. That’s why the running time is a little different, though it is the same hourglass. One more thing, the sand is not natural sand but glass beads. We’ll write a blog about the material of the sand.

Some customers would like to order sand timers in a set, like the mini plastic hourglass set for kids. So here comes the questions. The tolerance is 10%, so 5 Min 30 Sec is OK for 5 Min hourglass, while 5 Min 24 Sec is OK for 6 Min hourglass. Does that mean the running time of 6 Min hourglass can be less than 5 Min? Many customers will think about this, but this issue will never happen. We check this problem before packing. And rarely will customers order the hourglasses with so close running time.

If you need hourglasses with better accuracy, please feel free to let us know. We have helped a customer to produce 60 Minutes hourglass that the tolerance is 1 minute. Nothing different, just the price would be slightly higher than regular ones as we need more time to do the work.

We’ll update the article when we meet new ideas.