How To Measure Hex Holes With Go & No Go Gages

go & no go gages

During a manufacturing process, it is often a challenge to measure hexagonal (hex) holes. Hex holes are even harder to measure if they are internal (inside a compartment or object) because of varying reasons such as getting the right tools. This is the reason why Go & No Go gages are so useful in such processes. Typically, to make hex holes, a pilot hole is first done and then the sides are cut out to create the hex shape. The first stage usually presents few problems as a pilot hole is relatively easy to gage (such as with an air gage for example). The harder part comes when you are doing the sides as these usually determine how well the hex hole will fit into its intended part.

What Are Go & No Go Gages?

Go & No Go gages are simple gages that help machine operators determine the precision of hex holes that they make on objects. They are very popular because they are relatively simple to make and do not require any special material to coat them. They are usually designed to work within specific parameters and are shaped accordingly.

How Go & No Go Gages Work

The principle behind the Go & No Go gages is simple. If the machinist fits the go gage into the hex hole and it does not fit, the hex hole is tiny. If on the other hand the No Go gage fits, then the hole is too big. When the hex hole has been cut right, only the Go gage should fit perfectly. In a manufacturing process, the Go & No Go gages will be used on samples that are picked from the production line at fixed intervals. This way, the machinist can get a rough idea whether his or her hex holes are off and in case of the latter, corrections can be made before a large number of the products are made.

Why Go & No Go Gages Are Popular

Apart from them being easy to manufacture, Go & No Go gages are extremely durable as they do not suffer any severe pressure when in use. Most of these gages are hand-held and are used on select samples so if they are made with the standard tempered steel, they are unlikely to break or wear out from such use. The other advantage is that the simplicity of their use means that their operation can be explained to workers and machinists at any level without the need for complex training regimes. Usually the way they are designed, makes their use even easier.

The two gages are placed on separate ends of the same tool with a simple grip in the middle. The Go end of the tool is usually colored green while the No Go end of the tool is colored red. This way, it is almost impossible for a machinist to get the ends wrong while using the tool.

As you can see, this is a simple mechanism to help machinists gage hex holes and determine if they are in line with the set standard. Using a Go & No Go gage to size the ends to meet the required standards will ensure perfectly sized hex holes every time.

by George Chitos