16ME322 – TOOL DESIGN

UNIT – II

DESIGN OF INSPECTION GAUGE

A gauge or gage, in science and engineering, is a device used to make measurements or in order to display certain dimensional information. A wide variety of tools exist which serve such functions, ranging from simple pieces of material against which sizes can be measured to complex pieces of machinery. Depending on usage, a gauge can be described as "a device for measuring a physical quantity",for example "to determine thickness, gap in space, diameter of materials, or pressure of flow" or "a device that displays the measurement of a monitored system by the use of a needle or pointer that moves along a calibrated scale".

Various types of gauges include:

Name Description

bore gauge a device used for measuring holes.

a device used to measure the distance between two caliper opposing sides of an object.

are engineering gauges used in lathe work for checking the center gauges and fishtail gauges angles when grinding the profiles of single-point screw- cutting tool bits and centers.

16M322 – TOOL DESIGN / UNIT – II / DESIGN OF INSPECTION GAUGE Name Description

a ruler-shaped gage with two supports at each of its six sides, having tabs of varying lengths. For measuring the comb gage is pushed perpendicular into the film using the

comb type gage measuring range that corresponds to the expected film thickness. The wet film thickness will fall between the clearance of the shortest tab that is wet and the clearance of the next shortest dry tab.

dial indicator, also known as a dial an instrument used to accurately measure small linear test indicator, dial gauge, or probe distances. indicator

feeler gauge a simple tool used to measure gap widths.

a precision ground and lapped length measuring standard. It gauge block, (also known as a is used as a reference for the setting of measuring gage block, Johansson gauge, slip equipment used in machine shops, such gauge, or Jo block) as micrometers, sine bars, calipers, and dial indicators (when used in an inspection role).

gauge pin is similar to a gauge block. It is a precision ground cylindrical bar for use in Go/no go gauges or similar applications.

an inspection tool used to check a workpiece against its allowed tolerances. Its name derives from its use: the gauge

go/no go gauge has two tests; the check involves the workpiece having to pass one test (Go) and fail the other (No Go).

a flat steel block in the surface of which are two flat- bottomed grooves varying uniformly in depth from a maximum at one end of the block to zero near the other end.

grind gage Groove depth is graduated on the block according to one or more scales used for measuring particle size. Most gages will have one scale marked in either mils or micrometers.

16M322 – TOOL DESIGN / UNIT – II / DESIGN OF INSPECTION GAUGE Name Description

a transducer that is used to convert a force into electrical signal. This conversion is indirect and happens in two stages. Through a mechanical arrangement, the force being sensed deforms a strain gauge. The strain gauge converts the deformation (strain) to electrical signals. A load cell usually consists of four strain gauges in a Wheatstone

load cell bridge configuration. Load cells of one strain gauge (quarter bridge) or two strain gauges (half bridge) are also available. The electrical signal output is typically in the order of a few millivolts and requires amplification by an instrumentation amplifier before it can be used. The output of the transducer is plugged into an algorithm to calculate the force applied to the transducer.

a device incorporating a calibrated screw used widely for precise measurement of small distances in mechanical micrometer, sometimes known as a engineering and machining as well as most mechanical "micrometer screw gauge" trades, along with other metrological instruments such as dial, vernier, and digital calipers. Micrometers are often, but not always, in the form of calipers.

pressure gauge or vacuum gauge a device used for pressure measurement.

profile gauge or contour gauge a tool for recording the cross-sectional shape of a surface.

a tool used to measure the radius of an object. Radius gauges require a bright light behind the object to be radius gauge, also known as a fillet measured. The gauge is placed against the edge to be gauge checked and any light leakage between the blade and edge indicates a mismatch that requires correction.

a cylindrical ring of steel whose inside diameter is finished to

ring gauge gauge tolerance and is used for checking the external diameter of a cylindrical object.

strain gauge a device used to measure the strain of an object.

16M322 – TOOL DESIGN / UNIT – II / DESIGN OF INSPECTION GAUGE Name Description

a site along a stream where measurements of water surface

stream gauge elevation ("stage") and/or volumetric discharge (flow) are made.

a type of electrical transformer used for measuring linear displacement. The transformer has three solenoidal coils The linear variable differential placed end-to-end around a tube. The center coil is the transformer(LVDT) primary, and the two outer coils are the secondaries. A cylindrical ferromagnetic core, attached to the object whose position is to be measured, slides along the axis of the tube.

a device that measures temperature or temperature thermometer or temperature gauge gradient using a variety of different principles.

thread pitch gauge, also called a threading gauge, pitch gauge, or a device used to measure the pitch or lead of screw threads. screw gauge

a measuring device used either for determining the height of something, or for repetitious marking of items to be worked

vernier height gauge on. The former type of height gauge is often used in doctor's surgeries to find the height of people.

wire gauge measuring tool determines the thickness of a wire.

Go/no go gauge

A go-no gauge (or go/no-go) refers to an inspection tool used to check a workpiece against its allowed tolerances. Its name is derived from two tests: the check involves the workpiece having to pass one test (go) and fail the other (no-go).

16M322 – TOOL DESIGN / UNIT – II / DESIGN OF INSPECTION GAUGE

Snap gauge Snap gauges are often used when a large quantity of work pieces must be inspected.[4] The snap gauge has four anvils or jaws, the first one or pair (outermost) are set using the upper limit (tolerance) of the part and the inner set adjusted to the lower limit of the part. A correctly machined part will pass the first set of jaws and stop at the second—end of test. In this manner, a part may be checked in one action, unlike the plug gauge that needs to be used twice and flipped to access the second gauge.

The first go/no-go snap gage for checking thread rolls was invented in 1943 to speed production of parts during WWII

16M322 – TOOL DESIGN / UNIT – II / DESIGN OF INSPECTION GAUGE