Thread gauges are used to inspect threaded components by checking features like diameters, flank angles, and threads per inch. NO-GO and GO gauges efficiently inspect drafts, while plug gauges check holes. Types of thread gauges include plug gauges for nuts, solid thread ring gauges for externally threaded components, and adjustable thread ring gauges. Caliper gauges can also be used for mass production, though they are less precise than ring gauges. Proper gauge selection and application is important to ensure quality inspection of threaded components.

1. Understanding Thread Gauges
Why are thread gauges important for thread component inspection? We explain them
here.
Thread gauges are used in the assessment of threaded components. There are
many types of gauges used, but in production centers, inspection of holes and shafts for
acceptance levels is determined with a NO-GO and GO ring / snap gauges. They’re the
most efficient for inspecting drafts, while plug gauges are used to inspect holes.
With threading components, numerous features are usually checked such as the
thread’s major and minor diameters, flank angle, threads per inch and so on. Usually a
No / No Go inspects the part according to the pitch diameter. If there is a response to
the Go gauge, it means the part threads without being forced. If it responds to the No
Go gauge, the threaded part is unacceptable.
With bolt/screw threaded components, the above mentioned gauges are used, but there
are many other types that may be used depending on the situation.
• Thread plug gauge
A thread plug gauge is used to determine the acceptance of a nut. Just as
ACME thread gauges have variations, the same thing can be said here. For
small threaded components a double ended gauge is used with the Go and No
go ends attached respectively. For large components the unit may be in two. A
thread plug gauge is used to determine the pitch diameter.
For acceptance the Go gauge needs to pass the entire nut without requiring a lot
of force for rotation. The No Go gauge should be able to go through the nut, both
ends checked, but with not more than two turns.

2. • Solid Thread Ring Gauges
This is used to determine the acceptance of an externally threaded component
like a screw. Here the Go and No Go are separate, and they are used to check
the pitch diameter, thread depth and thread correctness. Here the Go gauge
needs to pass the screw without using too much force, and the No Go cannot do
more than a double rotation.
• Adjustable Thread Ring Gauge
These are ring shaped like thread ring gauges but they are split and have a
locking and adjusting screw for making minute adjustments. When these gauges
need to be set, setting plugs are required.
• Thread Caliper Gauges
The abovementioned gauges can be effective, but thread snap gauges or caliper
gauges can also be used. Some of these can be used with roller type Go
features that allow for faster inspection. In these instances they work via quick
sliding in the threaded component through the rollers.
Caliper gauges are not as precise as their ring counterparts, but they can be
useful for mass production where screws and other components need to be
checked quickly. These caliper gauges also allow for faster inspection on
components which slide on a gauge instead of screwing in. Unlike other
ACME thread gauges, caliper gauges don’t wear out as quickly.
In cases where caliper gauges are used, ring types are also present to conduct
random inspections to ensure quality standards are met.
These are the most types of threads used, and for the most part they will get the job

3. done. However for these to be effective the individuals using them have to be familiar
with their application.
Tips for Using Gauges
There are a lot of gauges for manufacturing inspection, and it is crucial that the right
ones be used. Not only is it necessary to use the right gauge, but proper application is a
must as well to avoid problems with the process. For this reason it is essential your
company buys only from a reputable source to ensure quality.
There are several ways to determine performance, but among the keys are calibration,
inspection speed and meeting the highest manufacturing standards. The nice thing
about thread gauges today is they come in different forms, from dial, limit gauges to
the digital variants. The fact there are several gauges to choose from should not deter
you, as it is actually going to make your job easier.