Identifying Thread Pitch & Size


welcome to this Swagelok how-to video in this segment we will look at identifying thread pitch and size thread pitch concerns are very important
to anyone who uses fittings or any threaded components here’s what you’ll need to perform the
procedure shown in this brief video a caliper a pitch gauge and a thread pitch identification guide let’s take a look threads have peaks and valleys referred to as crest and roots the surface between the crest and the
root is called a flank tapered threads which may also be
referred to as dynamic threads are designed to seal as the flanks of
the mating threads are drawn together thread sealant is required to fill in
the gaps between the crest and the roots to prevent system fluids from
penetrating the connection straight threads which may also be
referred to as parallel threads are not designed to seal they must rely on other factors such as
a gasket o-ring or some kind of metal to metal contact
to create a leak tight seal the first step toward identifying the
thread size and pitch is to determine whether the thread is
tapered or parallel tapered threads are at an angle in
relation to the centerline while parallel threads are parallel to
the centerline using a caliper to measure the nominal male or female thread crest-to-crest diameter on the first and last full threads if the diameter increases on a male end decreases on the female end the thread is tapered if all the diameters are the same the thread is straight now use the caliper to measure the
nominal male or female thread diameter from crest to crest for tapered threads measure the fourth or
fifth full thread for a parallel thread measure any full thread0:02:16.519,0:02:18.569
the next step is to determine the thread pitch use a pitch gauge and check the thread
against each form until you find a match some fractional and metric thread forms
are very similar so this may take a little time the final step is to determine the
thread standard take the information you have gathered thread category nominal diameter and the thread pitch and use a thread identification guide
such as this Swagelok threadand connection identification guide to identify the thread refer to swagelok dot com for
additional information thank you for watching we will continue to develop videos like
this to help you get the job done get more information by watching our other videos or contact your authorized sales and service center

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