Precision Measuring Tools

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Precision Measuring Tools
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blade micrometer Blade micrometer is a measuring device that has a thin blade to reach inside narrow recesses.

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The blade micrometer measures narrow grooves and keyways.

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Blade micrometer is used for measuring where the standard micrometer spindle could not be accommodated.

combination set Combination set is used as a rule, a square, a miter, a depth gage, a height gage, and a level.

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Combination set

The combination set consists of: blade, center head, protractor head, combination square head, scribe, and spirit level.

comparator Comparator graphically displays and measures dimensions and shapes that would be difficult to measure with regular tools.

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Also known as shadow graph

Optical measurement is a different and valuable aid to quality control. Capable of magnifying an object hundreds of times.
depth micrometer Depth micrometer measures depth of holes, slots, and other recesses.

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Measuring a depth of a slot.

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These micrometers come as a set with interchangeable rods to accommodate various measurements.

dial indicators

Dial indicators check alignment of machine components; show the variation of the object being measured. There are 2 types of dial indicators:

a. Balanced reading (has figures in both directions from the zero)

b. Continuous reading (numbered continuously)

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Dial indicators can be used to make linear measurements.

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Continuous reading dial indicator

disc micrometer Disc micrometer measures forming tools, cutting edges, narrow slots.

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The disc micrometer is also called a flange micrometer.

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This micrometer finds its application in measuring flanges and hard to reach areas.

gage block set Gage block set is also known as "Jo Blocks". Precision-round square or rectangular blocks are made of steel, chrome, or tungsten carbide.

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The measuring surfaces are lapped and polished to 200 milionths of an inch.

Gage blocks are used for:

- calibration and inspection of precision instruments
- to set comparators/indicators
- setting of sine bars
- precision layout
- machine setups

micrometer Micrometer is used to measure materials. It is available in metric and inch systems. The most common are the outside and inside micrometers.

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The most commonly used precision instrument.

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Available in different shapes and sizes

outside caliper Outside caliper measures an outside surface.

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The outside caliper is used to measure outside diameter.

Rules are also used for transfer measurements with calipers. It is used for semi-precision and comparison measurement. They depend on "feel" to measure a part.
plug gage

A type of "Go" or "No-Go" gage used to admit or refuse the inside dimension of an object.

There are three types:
- plain cylindrical
- cylindrical taper
- thread plug gage

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Available in different sizes

They are mounted at the ends of an aluminum handle. "Go" in one end and "No-Go" on the opposite end.
ring gage A type of "Go" or "No-Go" gage used to admit or refuse the outside dimension being checked.

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Ring gages are used as sets.

There are three types:

- plain ring gages
- taper ring gages
- thread ring gages

screw thread micrometer The 60 degree comparator micrometer is usually called a screw thread comparator micrometer or pitch micrometer.

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Measuring the pitch diameter of a screw thread.

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The pitch diameter, the most important measurement of a screw thread.

sine bar Sine bar is used for checking angles, typically used with gage blocks.

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Precise angles are measured using the sine bar.

The sine bar is a precision bar that has been hardened and then ground and lapped to very precise dimensions. It is also used for machine setups.
snap gage Snap gage gages diameters, lengths,and thickness.

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The adjustable limit snap gage is used to check outside diameter.

Various types of snap gages:

- adjustable snap gage
- adjustable roll snap gage
- dial indicator snap gage
square A square has two straight edges that form a right angle.

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A master precision square

A machinist uses several types of squares for a variety of jobs. A square is used for inspecting squarness and laying out work.
surface gage Surface gage is a scribing tool that draws lines parallel to a surface. When combined with test indicator, flatness, parallelism and heights may be inspected.

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The surface gage

Surface gages are designed for a variety of uses. The main uses are for scribing lines, transferring measurements and for probing surfaces in inspection work.
universal bevel protractor Universal bevel protractor is used to lay out, measure, or check angles.

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The bevel protractor can measure angles to five minutes of a degree.

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Vernier caliper Vernier caliper is a precision measuring tool capable to read within .001 inch. Used for inside, outside and depth measurements.

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The Vernier caliper

A Vernier caliper consists of a beam with a fixed measuring jaw, a sliding jaw witht he Vernier scale, and a mechanism for making fine adjustments.
Vernier gear-tooth caliper Vernier gear-tooth caliper measures gear teeth using two Vernier scales.

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Designed to measure the thickness of gear teeth.

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Vernier height gage It is rugged and reliable tool that gives precise and dependable measurements over long vertical ranges. It is also used for precision layout.

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The Vernier height gage

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