What is coarse thread metric?
5 (coarse) thread has a 1.5mm pitch, while an M10x1. 25 (fine) thread has a 1.25mm pitch. To simplify metric thread callouts, the international (ISO) standard for metric threads eliminates the pitch callout on coarse threads.
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Are metric threads fine or coarse?
Coarse is the most common metric thread and is assumed when pitch isn’t specified. What size Drill bit do I use to tap M…? Tip: To calculate the tap drill size for metric threads the diameter of thread minus the thread pitch will give you the required tap drill size. So for M6 x 1 thread size.

Is M8 fine or coarse?
Diameter
Diameter | Coarse Pitch | Fine Thread Pitches |
---|---|---|
M6 | 1.00 | 0.75 |
M7 | 1.00 | 0.75 |
M8 | 1.25 | 1.00 |
M9 | 1.25 | 1.00 |
What is M20 coarse thread?
Thread geometry – metric coarse
Thread | Major diameter | Pitch |
---|---|---|
M18 | 18.0 | 2.50 |
M20 | 20.0 | 2.50 |
M22 | 22.0 | 2.50 |
M24 | 24.0 | 3.00 |
Are metric threads different than standard?
Metric thread pitch measurements are read differently than standard ones. While for standard thread pitch measurements the lower number is coarse thread and the higher number refers to fine thread, in metric this is opposite. M10-1.50 is a coarse thread denotation while M10-1.25 is a fine pitch.

What is a coarse thread?
Bolts with coarse threads have a larger pitch (fewer threads per axial distance) compared to fine threads. A coarse threaded bolt is specified for most applications unless there is an overriding reason to use a fine threaded bolt (e.g. thorough thread adjustment is crucial for the application).
What are the different types of metric threads?
NPT/NPTF. BSPP (BSP, parallel) BSPT (BSP, tapered) metric parallel.
Is 18 thread coarse or fine?
Table 3.
Coarse | Fine |
---|---|
10-24 | 10-32 |
12-24 | 12-28 |
1/4-20 | 1/4-28 |
5/16-18 | 5/16-24 |
Is M5 coarse or fine thread?
Table 5.
Coarse | Fine |
---|---|
M5-0.8 | |
M6-1.0 | |
M7-1.0 | |
M8-1.25 | M8-1.0 |
What is M10 coarse thread?
Basic Metric Thread Chart (M1 – M100)
Diameter | Coarse Pitch | Fine Thread Pitches |
---|---|---|
M9 | 1.25 | 0.75 |
M10 | 1.5 | 1 |
M11 | 1.5 | 0.75 |
M12 | 1.75 | 1.25 |
What is the difference between imperial thread and metric thread?
Metric threads are measured by their pitch. That is the distance from the crest of one thread to the crest of the next measured in millimetres. The pitch of a metric thread can be checked by direct measurement with a metric rule. Imperial threads have their pitch measured indirectly as a given number of teeth per inch.
What thread count is coarse thread?
Standard Thread Pitch Chart
Coarse Thread Series – UNC | ||
---|---|---|
Nominal Size and Threads Per In. | Basic Pitch Dia. | Section at Minor Dia. |
3⁄8 – 16 | 0.3344 | 0.0678 |
7⁄16 – 14 | 0.3911 | 0.0933 |
1⁄2 – 13 | 0.45 | 0.1257 |
What number is coarse thread?
They are measured by finding the number of thread crests in 1″ of threads. They are separated into Coarse (NC, National Coarse) and Fine (NF, National Fine) threads….US Standard Thread Pitch.
Coarse Thread – NC | ||
---|---|---|
Thread | Decimal | Tap Drill |
10-24 | 0.1900 | 25 |
12-24 | 0.2160 | 17, 11/64 |
1/4-20 | 0.2500 | 7, 13/64 |
How to understand thread sizes?
Thread Sizes Explained – How to Understand/Read Thread Dimensions 1 1.Thread sizes in inches are specified by diameter and threads per inch. For example, in the screw size 10-24, the first… 2 2.Thread sizes in metric are specified by diameter and pitch. The metric thread sizes are generally expressed as M2 × 0. More
What is an ISO Metric thread?
ISO Metric Thread. The ISO metric screw threads are the worldwide most commonly used type of general-purpose screw thread. They were one of the first international standards agreed when the International Organization for Standardization (ISO) was set up in 1947.
What is a 6mm thread?
Thread sizes are given in nominal sizes, not in actual measurement. For instance, when a screw or bolt measures 5.9mm, it is called a 6mm thread. There are two common methods to write the thread dimensions.
What is the standard for a 60 degree screw thread?
The standard is in basic agreement with ISO screw standards and resolutions, as of the date of publication, and features detailed information for diameter-pitch combinations selected as to preferred standard sizes. This Standard contains general metric standards for a 60-degree symmetrical screw thread with a basic ISO 68 designated profile.