For a person who is new to metrology and inspection, he/she would find a supernumerary of options to work with. A thread ring gage is one such variant and is quite regularly put to usage for numerous threading operations. Primarily cylindrical in shape, it consists of a thermally stable metal whose diameter and gauge tolerance comes in handy when inspecting the outer diameter of a tubular object.

Thread ring gage – Utilization for comparative gauging:

Majority of ring gauges abide impeccable designing and is set as per the ANSI/ASME having X tolerance for- 1A, 2A, 3A (GO- as well as NO-GO members). They undergo manufacture with vivid tolerance grades both in metric as well as English dimension.

Both NO-GO and GO Ring gages- These consist of a fix gauge limit and aid in inspecting the Plus and Minus tolerances. Its dimensions base on the max OD tolerance of the oval bar.

According to ANSI/ANME B1.2- 1983

NO-GO ring gage’s functional diameter is only acceptable when its ring gauge does not pass over the thread over 3 absolute turns (without force).  As each gage is different in tolerance and style of threading! So, it’s better to consult a notable engineer when choosing the appropriate ring gages for the application.

Available Variants:

If you search for its availability, you will also come across ring gages existing apart from its general UN-Unified National Fix Pitch Series.

They include-

  • UNC- Unified National Course Series
  • UNEF- Unified National Extra Fine series
  • UNF- Unified National Fine Series
  • UNS- Unified National Special series

Some other series also exist. These sell through various thread gauges supplier with different tolerance grade for different micrometer, dimensional examination and period check-ups of the master gauge.

A tip from experts- the lower is the allowance variance from its nominal diameter when the grade is higher.

Modes of Using it to Perfection:

To speak the truth, both NO-GO as well as GO ring gages are easy to use. Here’s what to do:

  1. You should select the exact size of the ring gauge corresponding to your external threader. Experts state this is important to avoid incomplete or inaccuracy.
  2. Next, up is ensuring the right major Diameter, the TPI or Pitch or the class of fit. Along with that you also need to know if the ring gage is confirms the proper International or for that matter National standard.
  3. When selecting the ring gage, you have to ensure that it is correct to the pre plate pitch diameter (also known as pre-plate).  
  4. You should also check if the ring gage has undergone calibration. You may find some suppliers who don’t use basing frequency. So keep that point in mind.

The Right Thread Gauges Supplier:

Appropriate ring gages are important for your task precision. And you get quality requisites from notable suppliers.

So how to know if they are quality proven!

  • You have to see the number of years under their belt.
  • Check if they also manufacture and suppliers of gages, taps and dies.
  • See if they have instruments abiding ISO, DIN ASME, BS standards.
  • Examine their collection of instruments. The best will always have a vast assortment of GO, NO-GO (Right hand and Left hand tools).

Hopefully now you do have a fair idea about a thread ring gage. Plus you also know how to choose the right source for your tool. Make use of these details, procure your impeccable instrument and meticulously carry out your operation with confidence.

About The Author

Jeffrey Elder