threads and sealing methods

Identifying Threads, Sealing Methods and Identifying Threads, Sealing Methods and Industrial FittingsIndustrial Fittings

Module Objectives

Explain the basic thread characteristics necessary to identify threads

Module Objectives


Differentiate between and identify various types of threads used on industrial fittings

Module Objectives



Explain the various sealing methods used for the different fittings

Module Objectives



Explain the various sealing methods used for the different fittings

Identify different types of fittings being used in the industrial market place

Thread Characteristics


Thread pitch is the distance between a single thread

Pitch


Pitch:Pitch is sometimes written as the number

of threads within one inch distancee.g. 8 threads per inch


Flank Angle and Taper Angle:


Crest and Root: RootCrest


Major Diameter or OD:

Thread Style and Function

Thread StylesPort End Threads: Parallel

Parallel

Parallel Threads:

Thread Functions

Parallel threads only serve the function of holding in the fitting

Sealing is achieved by some other means, such as with an O-ring

Thread Styles

Tapered

Port End Threads:

Tapered

Thread Function

Tapered threads serve two functions:For holding in the

fittingSealing (even though

sealing is usually assisted with additional sealant)

Tapered Threads:

Thread ID Tools

Thread ID Tools

MIK-1 kitPort BoardsKnown ThreadsMarkings and Tables

Thread ID Tools

MIK-1 kit Caliper Thread gages Thread profiles Instruction

booklet Nose angle

indicator

Thread ID Tools

MIK-1 kit Caliper

Used to measure outside and inside diameter in either inch or metric units

Thread ID Tools

MIK-1 kit Thread gages

Used to compare thread form to determine pitch

Thread ID Tools

MIK-1 kit Thread profiles

Used to shadow pipe threads for determining nominal size

Thread ID Tools

MIK-1 kit Nose angle

indicatorUsed to determine

whether nose angle or seat is 37° or 45°

Thread ID Tools

MIK-1 kit Instruction booklet

(4303-B1)Contains

specifications for various thread forms

Thread ID Tools

Port Board Used to

determine male thread size based on comparison with known threads

Thread ID Tools

Other Known Threads Tube nuts or other components where

threads can be used for comparison

Thread ID Tools

Markings and Tables In some cases, fittings are marked with a

cross reference for threads Tables can be used to identify threads based

on given characteristics

Identifying Threads

Identifying Threads

1a. Verify if parallel or tapered Visual inspection

Steps for Identifying Thread Forms:

Identifying Threads

1b. Verify if parallel or tapered Compare with a known parallel


Identifying Threads

2. Determine thread pitch Use thread gages


Bad FitGood Fit

Identifying Threads

3a. Determine sizeMeasure with caliper or compare with

thread profile


Identifying Threads

Steps for Identifying Thread Forms

3b. Determine SizeCompare with Profile

Identifying Threads

4. Define thread Threads are called out according to the type

of thread They usually follow a standard pattern and

this is how they may appear on a print


Identifying Threads

4. Define thread NPT/NPTF - American Pipe Thread

Example: 1/4-18 NPT

1/4 = nominal size 18 = pitch (threads per inch) NPT or NPTF usually specified or NPT/NPTF

where it does not matter if it is either one


Identifying Threads

4. Define thread UN/UNF - Unified (SAE Straight Thread)

Example: 9/16-18 UNF

9/16 = actual size 18 = pitch (threads per inch) UN or UNF usually specified or UN/UNF where

it does not matter UNF is usually used for thread pitch above 12

TPI


Identifying Threads

4. Define thread BSPT - British Standard Pipe, Tapered

Example: R3/8

R signifies tapered 3/8 = nominal size The pitch is usually assumed based on known

standard Japanese taper thread would be written as PT

3/8


Identifying Threads

4. Define thread BSPP - British Standard Pipe, Parallel

Example: G3/4

G signifies parallel 3/4 = nominal size The pitch is usually assumed based on known

standard Japanese parallel thread would be written as PF

3/8


Identifying Threads

4. Define thread Metric Parallel

Example: M22X1.5

M signifies metric 22 = actual size in mm 1.5 = pitch (distance between threads in

mm)


Identifying Threads

4. Define thread Metric Tapered

Example: M10X1 keg (or tapered)

M signifies metric 10 = actual size in mm 1 = pitch (distance between threads in mm) keg is the abbreviation for the German word

meaning tapered and if the thread is tapered, it will be specified


Port End Sealing Methods


Female Port O-ring in chamfer

Available with • UN/UNF (SAE J1926)• Metric (ISO 6149)• BSPP (JIS B2351)


O-ring in chamfer (Male end)

Most reliable form of sealing

Available in adjustable fittings

ISO 6149 has special identification


Female Port Spot face sealing

Available with• Metric (DIN 3852-1)• BSPP (DIN 3852-2)

Wide variety of interchangeable male ends


O-ring in groove DIN 3852 Type E

O-ring not round in cross section

Adjustable not possibleSecond in pressure holding

capacity


O-ring w/ retaining ring DIN 3852 Type G & H

Separate metal ring surrounding o-ring

Adjustable fittings are type H


Bonded Seal DIN 3852 Type D

Elastomer bonded to metal ring

Undercut on fitting has taper angle

Adjustable not possible


Hard metal seal DIN 3852

Typically used on Banjo fittingsSeals by coining surface of portLimited reusabilityUseful for extreme

temperaturesAdjustable not possible


Soft Metal Seal DIN 3852 Type A

Seal material usually copper

Adjustable not possibleUndercut area has taper

angle


Cutting Face Seal DIN 3852 Type B

Sharp edge on fitting coins spotface for sealing

Limited reusabilityAdjustable not possibleUseful for extreme

temperatures


Female Port Taper threads

Available with• NPT/NPTF (SAE 476)• BSPT (DIN 3852-2)• Metric taper (DIN 3852-1)

Sometimes female port has parallel threads• Tapered male into female parallel allowed


Taper threads Sealing initiated by

thread interference Additional sealant

usually required Prone to fatigue failure Prone to galling

Tube/Hose End Sealing Methods

Tube End Identification

Tube/Hose Ends O-ring face seal (flat face seal) 37° flare 45° flare 24° flareless JIS 30° flare and 60° cone BSI (BSPP) 60° cone NPSM/NPT


Tube/Hose End O-ring face seal

SAE J1453ISO 8434-3UN/UNF ThreadHose,Inch or

metric tube


Tube/Hose End 37° flare

SAE J514ISO 8434-2UN/UNF ThreadHose, Inch or

metric tube


Tube/Hose End 45° flare

SAE J512UN/UNF

ThreadHose, Inch

tube


Tube/Hose End 24° flareless

SAE J514UN/UNF ThreadHose, Inch Tube


Tube/Hose End 24° flareless

DIN 2353ISO 8434-1Metric

ThreadHose, Metric

Tube3 pressure

series


Hose End JIS Cone

B8363BSPP Thread60° coneHose connection


Hose End JIS Flare

B8363BSPP Thread30° flareHose connection


Hose End Komatsu Flare

Metric Thread1.5 mm pitch (all

sizes)30° flareHose connection


Hose/Port End BSPP cone

BS B5200BSPP thread60° coneHose connection


Hose/Port End NPTF/NPSM

SAE J516NPT/NPTF male threadNPSM female thread30° chamfer or 60°

coneHose connection

Identifying Metric 24° Flareless Fittings


Identify markings Manufacturer’s logo Material code Tube size Pressure series


Determine Tube Size Measure sleeve ID

Identifying Metric 24° Flareless FittingsDetermine Tube Size

Measure tube OD


Measure fitting throat


Measure opening in back of nut


Determine thread pitch and size

Verify with specification table


Tube OD (mm) Pressure Series Thread size4 LL M8X16 LL M10X18 LL M12X1

10 LL M14X112 LL M16X16 L M12X1.58 L M14X1.510 L M16X1.512 L M18X1.515 L M22X1.518 L M26X1.522 L M30X228 L M36X235 L M45X242 L M52X26 S M14X1.58 S M16X1.5

10 S M18X1.512 S M20X1.514 S M22X1.516 S M24X1.520 S M30X225 S M36X230 S M42X238 S M52X2

JIS and BSPP 60° Cone Fittings

JIS and BSPP 60° Cone Fittings

Differences Thread length Chamfer diameter Undercut area Function (dual vs single) Interchangeability?

Hands on Exercise

Standards Activity and

Industry Trends

Standards Activity

Merging of BSI and JIS 60° Cone Adapters

ISO 16030 Pneumatic BSPP Port

High Pressure Multi-Bolt Round Flanges

Industry Trends

Metric Tube (plated)Elastomeric SealEO-2

Machine Tool BuildersISO 6149

Ag Equipment Manufacturers Engine Manufacturers

What’s available From TFD

What’s Available from TFD

K4 AdaptersTube Fabricating EquipmentMetric TubeEO and EO-2 Fittings & AccessoriesJIS FittingsConversion Adapters and PlugsMetric Triple-lokMetric Seal-lokMetric Tube Clamps

threads and sealing methods

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