Top 6 Commonly Used Gauges for CNC Machining

September 6, 2023

What is a Gauge?

A gauge, in science and engineering, is a device used to make measurements or to display certain dimensional information.
A gauge is an important inspection instrument in CNC machining process that measures a part’s dimensions against the maximum and minimum permitted limits. It is commonly used to separate acceptable and non-acceptable parts without knowing the exact dimension value.

Why do We Need Gauges?

There are many benefits by using gauges in CNC machining process. The following are some of the reasons why we utilise gauges.

They are portable, simple to set up, and do not require any additional equipment. So they can be used not only in OQC but also in IPQC.
Dimension may be examined in a variety of ways to assist in the constant production of high-quality parts.
They are more affordable than measurement devices which will help to reduce manufacturing cost.
It is possible to quickly check whether the part is within its stated limit to reduce production waste by detecting incorrect parts before they are finished.
There is less reliance on operator competence, so the outcome is not influenced by operator judgment.

What are the Gauges commonly used in CNC Machining?

What are the Gauges commonly used in CNC Machining?

No.	Name	Description	Description
1	Height Gauge	A height gauge is a measuring device that measures the height of machined parts from a datum reference. The height gauge consists of a rigid column mounted to flat base with a measuring head that displays height from the bottom of the base on a dial, vernier, or digital display.
2	Calliper Gauge	A calliper gauge is an instrument used to measure the dimensions of machined parts, generally by placing two movable points of the instrument across the parts to be measured, which reads out a measurement on a ruled scale, a dial, or an electronic digital display.
3	Plug Gauge	A plug gauge, a double-ended type, is a fixed mechanical inspection instrument used to verify compliance of threaded or plain holes that are machined into manufactured parts, components, or assemblies. A plug gauge comes with different diameters. Plug gauges are designed to “fit” or “not fit” (e.g. Go/No-Go gauge) into holes, etc, which determines if a hole diameter or thread feature lies within the specified range of acceptance.
4	Block Gauge	Block gauges (also known as gage blocks, Johansson gauges, slip gauges, or Jo blocks) are a set of precision ground and lapped blocks of different lengths that can be stacked to form precision lengths (or height) for highly-accurate linear measurements. The individual block is a metal or ceramic block that has been precision ground and lapped to a specific thickness.
5	Pin Gauge	Ping gauges are precision ground cylindrical bars used to measure holes or inner diameters that cannot be simply measured by micrometers or calliper gauges and so on. They are commonly used similarly to a Go and No-Go Gauge to verify whether a hole or inner diameter are within a certain specification. Pin gauges are only useful for checking the straightness of a deep hole.
6	Ring Gauge	A ring gauge is a steel cylinder ring with an interior diameter polished that is verify the outside diameter of a cylindrical parts compliance to upper and lower dimensional limits. Ring gauges are used as a quick pass / fail test to determine if the outside diameter or thread feature of a part lies within the specified range of acceptance. Pins, shafts, splines, fasteners, dowels, studs, and other machined cylindrical parts may all be measured with ring gauges.