Information About Types of Gauges

We can classify the types of gauges as follows:

Gauge Blocks (Parallel Gauges)

These are made in the shape of a rectangular prism from high-carbon stainless steel. Their surfaces undergo extremely precise processing. Their measuring surfaces are made so precisely that when combined together to achieve a certain dimension, they adhere to each other strongly. Testing has shown this adhesion force to be around 40 kg/cm².

Properties of Gauge Blocks

1. Each gauge block in a set has its own dimensional accuracy, and the desired measurement precision can be achieved at the desired sizes.
2. By combining several gauge blocks together, the desired length can be achieved quickly and easily.
3. Taking advantage of the surfaces’ flatness, parallelism, and dimensional accuracy, the desired tolerances can be easily achieved.
4. The properties of combined gauge blocks remain unaffected as long as there’s no dropping, striking, or similar impact. For this reason, their use in industry is increasing day by day

Gauge series are built starting from the last digit of the dimension. That is, starting from the smallest gauge that makes up the series.

If dimensional accuracy is being achieved by combining two or more gauge blocks, protective wear blocks that stay permanently attached should be fixed to the top and bottom surfaces of the gauge block stack. This way, the other gauge blocks are protected from scratching, impact, and similar effects

Materials of Gauge Blocks

Gauge blocks are generally made from carbon steel and hardenable, wear-resistant chromium-alloy steels. Materials used for gauge blocks need to have the following properties: they must harden well, must not change shape during hardening, must be resistant to wear, must have a very low elongation percentage, and the material must be low-cost and easy to machine.

Gauge blocks are also made from nickel-alloy steels and stainless steels to increase wear resistance. They’re also manufactured from hard metals such as tungsten carbide and chromium carbide. However, gauge blocks made from hard metals are quite costly. Depending on the application, some gauge blocks are also made from copper, quartz, and aluminum alloys

Profile Gauges

Profile gauges are used for checking parts’ characteristic profiles, cross-sections, wire diameters, cutting edges, and similar features.

Thread-Cutting Tool and Thread Pitch Gauges

They’re used to ensure that thread-cutting tools have the correct profile for the thread being cut, and to check the thread once it’s cut

Limit Gauges

Also known as Go-No Go gauges.

The upper and lower limit dimensions of toleranced parts can be checked with a male gauge for corresponding holes, and with a female gauge for shafts.

The Go gauge checks the largest allowed dimension on shafts and the smallest allowed dimension in holes.
The No-Go gauge checks the largest dimension in holes and the smallest dimension on shafts. A workpiece that fits the No-Go gauge is scrapped

Plug Gauges

(Plug Gauges) Used for checking holes and grooves. The Go side should enter the hole under its own weight. It represents the lower tolerance limit of the hole. Only the tip of the No-Go side should enter. It represents the upper tolerance limit of the hole.

The Go side has a long cylinder, fitted with hard-metal bars to reduce wear. The No-Go side has a short inspection cylinder. This part of the gauge is marked in red, with the upper dimension limit printed on it.

On limit gauges, the part the workpiece can pass through is marked with the word “Go,” green, or no color at all; the part the workpiece cannot pass through is marked with the word “NoGo” or red.

Checking Tolerance With a Go/No-Go Plug Gauge

The video above shows how a plug gauge is used and how tolerance is checked with a Go/No-Go plug gauge.

Snap Gauges

(Snap gauges) Among the types of gauges, snap gauges are used to check the diameter and thickness of workpieces. The Go side has the largest allowed dimension and passes over the part being checked under its own weight. The No-Go side is made slightly shorter, with a small tolerance difference. The No-Go side also has angled inspection surfaces and is marked in red, with the lowest limit value printed on it.

35 f6 Snap gauge, Go position.(above)

The No-Go position of the snap gauge for the same workpiece. We can say this workpiece was machined within tolerance.

A progressive snap gauge, where the Go and No-Go parts are designed one after the other on the same piece

An adjustable snap gauge where the Go and No-Go parts are designed one after the other on the same piece, adjustable according to the nominal dimension and tolerance value

Checking Tolerance With a Go/No-Go Snap Gauge

The video above shows how a snap gauge is used and how tolerance is checked with a Go/No-Go snap gauge.

Ring Gauges

Thread Gauges

(Thread gauges) These gauges are used for checking threads cut into internal or external cylindrical surfaces. With this check, we can precisely verify whether the major diameter, minor diameter, pitch, and tooth shape of the thread will provide good contact.
Their difference from thread pitch gauges is that they offer more precise and reliable checking.

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