What is the metric thread
Metric threads are designated by the letter M followed by the nominal major diameter of the thread and the pitch in millimeters. For example M10 x 1.0 indicates that the major diameter of the thread is 10mm and the pitch is 1.0mm. The absence of a pitch value indicates that a coarse thread is specified. For example stating that a thread is M10 indicates a coarse thread series is specified of diameter 10mm (giving the thread a pitch of 1.5mm).
Measure metric threads
For Metric parallel threads, taking a caliper reading of the threads outer diameter in millimetres (mm) will give a reading of the exact thread size but not the thread pitch. For example, a caliper reading of 12.03mm indicates it is very likely a 12mm thread. We still do not know however if it is 1.0 or 1.5 thread pitch (or some other pitch).
These steps should be taken in order to ensure you have successfully identified the proper Metric thread:
- Identify if the thread is parallel or tapered
- Determine the thread pitch in mm using a thread gauge or calipers (typically 1.0, 1.5, or 2.0, but other sizes do exist)
- Determine the thread O.D (male thread) or I.D (female thread) using calipers.
- Find the closest match on the adjacent chart (thread O.D and pitch combine into a “thread callout” such as M12 x 1.5 indicating a 12mm O.D with 1.5mm pitch)
- If a seal or angled sealing surface exists, use it to identify which specific type of Metric fitting it is on next page’s chart.
QC Hydraulics is carrying on very large types of metric fittings and metric DIN tube fittings.
Please feel free to contact our sales team if any demands.