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Types of screws PS and PF Is it possible to share thread machining tools and gauges?

Both are parallel screws for pipes, but the tolerance settings are different.

Gauges cannot be shared with machining tools.

division	Male thread	Female thread	combination
for tight coupling Tapered screw for pipes Example: Prevent water and gas from leaking	R(PT) Taper	Rc(PT) Taper
		Rp(PS) parallel
mechanical coupling Pipe parallel screw Examples: Protection tubes for wiring cables, etc.	G(PF) parallel	G(PF) parallel

The effective diameter of the internal thread is different between PF and PS. You cannot use a PS tap on a PF female thread, and you cannot use a PF tap on a PS female thread.

PS has a negative tolerance from the standard dimension with an emphasis on tightness, and PF has a positive tolerance from the standard dimension with an emphasis on fit. If the screw for tight coupling (Rp/PS) is processed with a tap (G/PF) for mechanical coupling, there is a risk of leakage because dense resistance cannot be obtained.

When selecting machining tools and gauges, please select the type of screw in the drawing instructions.