Metric Bolt Thread Pitch

Ultimate tensile and proof loads for metric bolts according iso 898 1 mechanical properties of fasteners made of carbon steel and alloy steel part 1.

Metric bolt thread pitch. M12 x 25 12 mm diameter coarse thread is assumed 1 75 mm 25 mm long. Bolts screws and studs with specified property classes coarse thread and fine pitch thread. The thread angle is 60 o. The thread pitch is the distance between threads expressed in millimeters measured along the length of the fastener.

M metric thread designation. Bellow are iso din accepted thread pitch charts for commonly found metric fasteners. As i explained at the top of the page metric bolt sizes are stated as diameter x distance between threads x length. The thread depth is 0 614 x pitch.

This bolt is one half inch in diameter has 13 threads per inch and is one inch long. An example of a sae bolt size is 1 2x13x1. Maximum rounded form minor diameter d 3max d 2max 0 5h 2r min 1 cos 60deg arccos 1 t d2 4r min. For example a thread pitch of 1 5 means that the distance between one thread and the next is 1 5mm.

Sae bolts will not thread perfectly into a metric nut or metric threaded hole. Bolt depot common metric thread pitches standard fine super fine jis. 20 length in millimeters see below this example illustrates how a coarse threaded screw may appear. American or sae bolt sizes are expressed as diameter x thread pitch x length.

Thread pitch is the number of threads per inch. 1 0 pitch distance from thread to thread in millimeters. The metric system s pitch is commonly viewed as the reverse of tpi in that it is the distance measured between two adjacent threads. Metric thread pitch table metric pitch table metric diameter pitch mm coarse standard fine standard 3mm 0 50 0 35 4mm 0 70 0 50 5mm 0 80 0 50 6mm 1 00 0 75 8mm 1 25 1 00 10mm 1 50 1 25 12mm 1 75 1 25 14mm 2 00 1 50 16mm 2 00 1 50 18mm 2 50 1 50 20mm 2 50 1 50 22mm 2 50 1 50 24mm 3 00 2 00 27mm 3 00 2 00 30mm 3 50 2 00 33mm 3 50 2 00 36mm 4 00 3.

In the imperial inch system threads are commonly referred to by measuring an inch and counting how many threads are inside that measurement. The rest of the dimensions are tabulated values from the asme standard. 8 nominal diameter in millimeters. Thread pitch metric fasteners are specified with a thread pitch instead of a thread count.

Here r min is minimum root radius t d2 is pitch diameter tolerance and h is height of sharp v thread. The smallest or largest pitch diameter that fits onto a screw or into a nut including all of the form deviations such as lead thread angle taper and roundness.