Page 15 - Threading_Handbook

1.3 Thread Standards

To ensure the interchangeability of threaded products for the main parameters of thread
profiles, it is necessary to set the appropriate standards.

The Most Common Standards According to Their Purpose INTRODUCTION
Machinery and General Use Aerospace Industry

ISO UN UNJ MJ
NUT NUT NUT NUT
1/4 TP 1/4 TP
60° 60° 5/16 TP 5/16 TP
60° 60°

1/8 TP 1/8 TP REmax 0.18042TP REmax 0.18042TP
SCREW SCREW REmin 0.15011TPSCREW REmin 0.15011TP SCREW

Pipe Threads (Connection, Fittings and Sealing)

BSW BSPT NPT NPTF
NUT 0.137TP NUT NUT NUT
0.137TP
55° 27.5° 30° 30° 30° 30°

0.137TP 90° 0.137TP 90° 1°47' 90°
SCREW 1°47' SCREW SCREW 1°47' SCREW

Trapezoidal Worm Threads for Power Transmission
American
Trapeze Acme Stub Acme Buttress Metric Buttress
NUT NUT NUT TP NUT NUT
30° 29° 29° 45° TP

7° 3° 30°
SCREW SCREW SCREW SCREW SCREW

Oil & Gas Industry for Pipes and Couplings
API Round Exteme Line Casing API Buttress Casing
NUT NUT TP NUT NUT
30° 30° 6° 6° 30° 30° 3° 10°

IPF
TAPER 1:16 90° TAPER- IPF 90° SCREW 90° IPF 90° IPF
SCREW SCREW SCREW

Fire Fighting and Electric Cable Connectors - Join Pieces of
Food Industry Pipe Couplings Electrical Conduit and Cable Glands
RND PG

0.22105TP NUT NUT
0.25597TP
30°
80°
0.23851TP SCREW
SCREW

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