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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