Detailed Explanation of Plug Gages, Their Functioning and Uses

Plug Gages

Explained in simple terms, a plug gage is used to check the size of the drilled holes. This is extremely important in applications where the pre decided size of the drilled hole must be achieved. This can be done in two ways. The first way is to check the size of the drilled hole during the manufacturing process, i.e. On-line or Real Time Inspection. Second method is to check the sizes after the gage is manufactured. These gages can be straight or tapers, plain or threaded, depending on the customer's needs.

Here, the concept should be noted that a gage is not a plug but a tool for measuring whether the given screw or plug will fit into the hole.

Working of Gages

These gages are inserted into the drilled hole. If the gage slips in the hole for the given size then the hole is said to be correctly manufactured. There are different types of gages available for measuring different types of small parts such as screws, nuts.

The Go and No GO Concept

There is a concept called ‘GO' and ‘No GO'. As the name suggests a go measure tells us how much the part to be fitted in the hole goes ‘inside' of the hole. While a no go measure tells us how much part of it should not go ‘inside' the hole. Hence if a gage ‘goes in' exactly as per the ‘GO' measurement and ‘does not GO' as much as told in the ‘NO GO' measurement, it is said to be manufactured correctly.

Manufacturing Plug Gages

Since Carbide balls give maximum wear resistance and hardness, gages are made of Tungsten Carbide. They give the required tolerance levels in the risky (prone to hazards etc.) environment of factories.

Uses

Types of these gages are - Taperlock, Cylindrical Taper, Trilock, and Reversible gage. These gages return a state whether the drilled hole is acceptable or not acceptable and hence one does not have to measure the actual sizes etc. of any of the parts. Hence, their use can be found mostly in production industry where very little skills are little interpretation is needed. Plug gages are used in design and, mechanical engineering and water flow engineering etc..

Tolerance Levels

There are various tolerance levels, four important ones among them are X, Z, XX and ZZ. More than any other property, Gages are determined by their tolerance levels.

Selecting Suitable Gage for Your Need

There are many factors to consider before selecting plug gages for your needs. Few among them are mentioned here – Maximum Tensile and Compressive and transverse rupture Strength of the carbide balls since they have wear parts. The maximum temperature should also be considered in which the gage can work.

About the Author

Machining Technologies of known worldwide for its a high-tech, state-of-the-art manufacturing facility. We have progressively expanded our manufacturing and worldwide product line to include wear parts components, tungsten carbide balls, stainless steel balls, carbide blanks, plastic balls, tungsten carbide, and plug gages.

Plug Gages to Combat Hostile Production Environment

Ask the importance of plug gages to anyone who deals in machining tools in the manufacturing industry? The answer you would get is that ‘they are integral to ensure quality in all types of manufacturing processes'. Yes, also referred to as Go-NoGo gauge, it helps in the inspection of tools used to check a work piece against its allowed tolerances. You can conduct the test in two ways- a work piece that pass the ‘GO' test and another that goes the ‘NO GO' test.

Importance of Go/No Go Tests

As has been mentioned earlier, the Go/No Go tests using plug gages are important to gauge the quality of various machining components required in large manufacturing units. This is required for various processes like ensuring interchangeability of parts between processes and also between that of different manufacturers. The system of using plug gages to suit the quality needs of a particular manufacturer holds especially profitable in the production area of the factory as they require less skill or interpretation to use them effectively for the purpose of quality measurement. Moreover, they have no/few moving parts and hence, there are very less chances of getting damaged due to hostile production environment.

Working Principle of Plug Gages

The devices are used as plugs, hence the name plug gages. Well, using them for the purpose of getting precision measurement is quite simple. All you have to do is insert one end into the part first and depending on the result of that test, the other end is tried. These devices are threaded wherein the part to be tested is screwed on the part that is labeled GO where it enters fully and then there would be the NOT GO end where it should not fit totally. Accordingly to their area of operation, these devices are divided into hardened and ground gaug e or replaceable thread gauges.

Selecting the Best Plug Gages

With the growing importance of these measuring devices, many manufacturers have come up with different varieties of gages of varied make and dimensions. It is very important that you choose the ones that fit your needs to best of its ability to prevent wear parts. I recommend that you get custom gages that are built to your specifications that are developed from your part drawings. Buy only those that abide by ANSI/ASME B89.1.5. To get the best from these plug gages, always store them a secure location, preferably in individual containers. And, also dip all ball gages in an oil/wax based seal or coated with a rust preventive prior to storing for longer shelf life.

About the Author

Machining Technologies of known worldwide for its a high-tech, state-of-the-art manufacturing facility. We have progressively expanded our manufacturing and worldwide product line to include wear parts components, tungsten carbide balls, stainless steel balls, carbide blanks, plastic balls, tungsten carbide, and plug gages.