Thread Identification Our guide to identifying the most common threads

Thread Identification guide to common threads including BSP, JIC, ORFS, Metric, Flanges and more from Apex Fluid Power.
Simply click the links below to be taken direct to the thread identification for that type.
We can also provide a PDF/hard copy for easy reference in the field. Please contact us and we will get this to you ASAP.
Or simply phone us on 01228 511157 and let us help you with sizing the correct thread.


BSP Thread Identification

British Standard Pipe (BSP)

Also referred to as Whitworth threads, the BSP thread type fittings seal using metal to metal angled surfaces or a combination of metal to metal and an O-ring. The angle of the sealing surfaces is 60° for both forms.
There are two popular thread forms, British Standard Pipe Parallel (BSPP) and British Standard Pipe Tapered (BSPT).

Identification is made by measuring the outside diameter of the thread and the number of threads per inch (25.4 mm)

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How to measure BSP thread
Dash SizeSize (inches)TPIMale O/D (mm)Female I/D (mm)Hex
-21/8289.78.914
-41/41913.211.919
-63/81916.515.222
-81/21420.819.127
-105/81422.420.330
-123/41426.424.632
-16111333141
-201.1/41141.939.650
-241.1/21147.845.555
-3221159.757.470

JIC Thread Identification

JIC - Joint Industry Council Thread - SAE JIC 37°

Commonly referred to as just JIC fittings these metal to metal sealing type fittings have a 37° flare (sealing surface angle) and straight United National Fine straight Threads (UNF).
The original design specification for the fittings comes from the Society of Automotive Engineers (SAE) and these fittings are the most common American fitting type in Europe.

Standard
ISO 12151-5 2), ISO8434-2 and SAE J516

The most commonly found sizes on hydraulic hose are below:
1/4" hose - 9/16" JIC
3/8" hose - 9/16" JIC / 3/4" JIC
1/2" hose - 7/8" JIC
3/4" hose - 1.1/16" JIC
1" hose - 1.5/16" JIC

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How to measure JIC thread
Dash SizeSize (inches)ThreadMale O/D (mm)Female I/D (mm)Hex (mm)
063/824 UNF9.68.612.7
077/1620 UNF11.29.914.3
081/220 UNF12.711.415.9
099/1618 UNF14.212.917.5
123/416 UNF1917.522.3
147/814 UNF22.320.325.4
171.1/1612 UN26.924.931.8
191.3/1612 UN30.028.235.0
211.5/1612 UN33.331.338.1
261.5/812 UN41.439.250.8
301.7/812 UN47.745.557.2
402.1/212 UN63.561.470.1

Metric Thread

DIN 24° Light (L) and Heavy Series (S) with O-ring

The male has a 24° sealing angle cone seat with straight metric threads.
The female has a 24° convex cone with O-ring and a swivel straight metric threaded nut.

Standard
ISO 12151-2 / ISO 8434-1 & ISO 8434-4

The most commonly found sizes on hydraulic hose are below:
1/4" hose - 10L Metric
3/8" hose - 12L Metric
1/2" hose - 15L Metric
3/4" hose - 22L Metric
1" hose - 28L Metric

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How to measure Metric thread
Tube O.D. LightTube O.D. HeavyThreadMale O/D (mm)Female I/D (mm)
6mm / 6L M12x1.512.010.5
8mm / 8L6mm / 6SM14x1.514.012.5
10mm / 10L8mm / 8SM16x1.516.014.5
12mm / 12L10mm / 10SM18x1.518.016.5
 12mm / 12SM20x1.520.018.5
15mm / 15L14mm / 14SM22x1.522.020.5
 16mm / 16SM24x1.524.022.5
18mm / 18L M26x1.526.024.5
22mm / 22L20mm / 20SM30x2.030.028.0
28mm / 28L25mm / 25SM36x2.036.034.0
 30mm / 30SM42x2.042.040.0
35mm / 35L M45x2.045.043.0
42mm / 42L38mm / 38SM52x2.052.050.0

ORFS Thread

O-ring Face Seal (ORFS)

ORFS fittings are becoming the most popular international fitting type used on global OEM machines due to their high level of sealing and their good vibration resistance. The fittings use the O-ring compression mechanism to seal.
The female fittings have flat faces and straight threaded UNF swivel nuts. The male fittings have the O-ring in a groove in the flat face.
Seen as a major advantage, these fittings offer the possibility to build the hose assemblies into fixed distances/spaces, without having to move back other system components due the flat faces of the male and female fittings - the hose assembly can be slotted in.

Standard
ISO 12151-1, ISO8434-3 and SAE J516

The most commonly found sizes on hydraulic hose are below:
1/4" hose - 9/16" ORFS
3/8" hose - 11/16" ORFS
1/2" hose - 13/16" & 1" ORFS
3/4" hose - 1.3/16" ORFS
1" hose - 1.7/16" ORFS

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How to measure ORFS thread
Dash SizeSize (inches)ThreadMale O/D (mm)Female I/D (mm)Hex (mm)
099/1618 UNF14.112.919.0
1111/1616 UNF17.415.922.0
1313/1616 UNF20.619.127.0
16114 UN25.223.630.0
191.3/1612 UN30.028.036.0
231.7/1612 UN36.334.441.0
271.11/1612 UN42.740.150.0
32212 UN50.648.560.0

Flange Thread

Code 61 Type

The 4-bolt split flange (or full flange) fitting is used worldwide for connecting high pressure hoses typically to pumps, motors and cylinders, where the hose assemblies are subjected to large pressure loadings.
The sealing mechanism is through compression of the O-ring in the face of the flange head against the surface of the port/ connection.
The flange fittings are generally separated into two pressure classes referred to as 3000 psi (SFL) or 6000 psi (SFS).
ISO 12151-3 refers to the flange fittings as code 61 for the 3000 psi and code 62 for the 6000 psi.
In addition to these flanges, customer specific Komatsu® and CATERPILLAR® flanges can also be found in the market.

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How to measure Flange thread
Dash SizeSize (inches)Working Pressure (psi)Flange Dia (mm)Flange Thickness (mm)Hole Centres (mm)
081/2500030.26.731.8
123/4500038.16.747.6
161500044.48.052.3
201.1/4400050.88.058.7
241.1/2300060.38.069.8
322300071.59.577.7

Flange Thread

Code 62 Type

The 4-bolt split flange (or full flange) fitting is used worldwide for connecting high pressure hoses typically to pumps, motors and cylinders, where the hose assemblies are subjected to large pressure loadings.
The sealing mechanism is through compression of the O-ring in the face of the flange head against the surface of the port/ connection.
The flange fittings are generally separated into two pressure classes referred to as 3000 psi (SFL) or 6000 psi (SFS).
ISO 12151-3 refers to the flange fittings as code 61 for the 3000 psi and code 62 for the 6000 psi.
In addition to these flanges, customer specific Komatsu® and CATERPILLAR® flanges can also be found in the market.

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How to measure Flange thread
Dash SizeSize (inches)Working Pressure (psi)Flange Dia (mm)Flange Thickness (mm)Hole Centres (mm)
081/2600031.87.740.5
123/4600042.38.750.0
161600047.69.557.1
201.1/4600053.910.366.7
241.1/2600063.512.679.4
322600079.412.696.8