What is the measuring tool for extra long stainless steel machine screws?

Generally, when we measure the length of screws, we use vernier calipers. Are these tools used to measure the length of the extra long stainless steel machine screws?

Generally, vernier calipers of digital display classes can measure 150mm in length, which is quite common. This length vernier caliper measures almost all screws. But extra long stainless steel machine screws are not the same. They are usually more than 100mm in length, and sometimes reach more than 800mm, 1000mm, and so on. How is such a long length measured?

Such a long screw is usually measured with a longer vernier caliper, such as a 300mm vernier caliper. Or if the screw is longer, you can use a ruler to measure it. Some people will say, isn’t it inaccurate to measure with a ruler?

Generally speaking, it is not accurate to measure with a ruler, but it depends on the size of the screw. If the screw length is 8mm and their tolerance range is only 7.7mm-8mm, then measuring with a ruler would be very inaccurate. But the length of the extra long stainless steel machine screws is too long, their tolerance range will be larger. For example, the length of the screw is 560mm, so their tolerance range is 558mm-562mm, which can be measured with a ruler.