Thread Designation & Dimensional Calculation

Thread Designation

Outer dimensions, thread type and pipe connection size of a nozzle in the drawings and data tables appeared in our catalog are denoted in accordance with ISO standards.
However, for ordering or sending inquiries, they are denoted according to our coding system. For details, please refer the following cross reference of thread type designation.
Unless otherwise specified, our products have taper pipe threads.

ISO standards Old JIS IKEUCHI's coding system NPT standards (USA)(*4) BS standards (UK)
Taper pipe thread Male taper thread R PT M NPT BSPT
Female taper thread Rc F
Parallel pipe thread Male parallel thread G (*1) PF M NPS BSP(P) or
Female parallel thread G F
Female parallel thread Rp (*2) PS (*3) F - -
Metric thread Fine pitch M M M - -
Coarse pitch - -

*1) Denotation of pipe connection size followed by effective diameter tolerance class "A" or "B".
*2) A female parallel pipe thread used with a male taper pipe thread.
*3) A taper pipe thread not in ISO standards.
*4) NPT and ISO threads are not compatible due to the differences in their thread forms. ISO thread is compatible with BSP threads.

Our catalog description example

Diagonal Dimension of a Hexagonal Nozzle Shape

To calculate the diagonal dimension of hexagonal geometry, the approximate value can be estimated by multiplying the width across the flats by 1.16.

(Example) In the figure at right, the dimension H is 12 mm, so the diagonal dimension is 13.92 mm ( = 12 x 1.16).