Measuring Metric Screw

In order to measure the diameter of a screw correctly, one must note that one measures on the thread and does not accidentally place the caliper between the thread. If you insert the screw crosswise into the caliper, the probability of a measuring error is very high, because the jaws of the caliper can slip between the threads. The screw must therefore be inserted lengthwise to the legs of the caliper. The diameter of a screw is always measured on the thread.

In order to measure the length of a screw correctly, it is necessary to know that the part of the screw that can be screwed into the material is indicated as the screw length.

For cylinder head screws or pan-head screws, for example, only the thread length is measured, i.e. from the underside of the screw head to the tip of the screw. This can best be measured with the caliper depth gauge, see the picture on the left. Only the part that penetrates into the material is measured!

But watch out! Countersunk head screws are an exception here, here the head of the screw is also measured, as it disappears completely into the material when screwed in. With countersunk screws you can clamp the entire screw between the two jaws and measure the screw length, see picture on the left.

Measuring a screw correctly is not difficult with a caliper gauge and now you know how to do it!

You don't have a caliper yet, then you can buy it here.. 

In order to measure the diameter of a wood screw correctly, one must note that one measures on the thread and does not accidentally place the caliper between the thread of the wood screw. If you insert the screw crosswise into the calliper, the probability of a measuring error is very high, because the jaws of the calliper can slip between the threads. The screw must therefore be inserted lengthwise to the legs of the caliper. The diameter of a screw is always measured on the thread.

In order to correctly measure the length of a wood screw, it is necessary to know that the part of the screw that can be screwed into the material is indicated as the screw length. For wood screws with a lens head, for example, only the thread length is measured, i.e. from the underside of the screw head to the tip of the screw. This can best be measured with the depth gauge of the caliper gauge. Only the part that penetrates into the material is measured!

But beware! Wood screws with countersunk head are an exception here, here the head of the screw is also measured, since this disappears completely in the material when screwing in. With countersunk screws you can clamp the entire screw between the two jaws and measure the screw length, see picture on the left.