Engineering Metrology Questions and Answers – Radius Gauges

1. Which of the following is another name of radius gauge?

  1. Ring gauge
  2. Thickness gauge
  3. Fillet gauge
  4. Plug gauge

Answer.3. Fillet gauge

Explanation:-

The radius gauge resembles a feeler gauge with the difference that feeler gauge blades vary in thickness whereas, the radius gauge blade tips are designed to measure external and internal radius on each blade.

The blade used for measuring external radius is called ‘Radius Gauge’ whereas, the blade used for internal radius is called “Fillet Gauge‘.

 

2. The measuring range of radius gauge is

  1. 0.00075-0.025 m
  2. 0.0075-0.5 m
  3. 0.075-5 m
  4. 0.75-5 m

Answer.1. 0.00075-0.025 m

Explanation:-

Three sets of radius gauges are manufactured for different measuring length

  • Set 1 measures the radius available from 0.6-0.8mm.
  • Set 2 measures 1 – 7mm,
  • Set 3 measures 6mm – 25mm.

The object or workpiece whose radius is to be measured is taken and the blades are inserted one by one to check which one fits in exactly by comparing it with the radius on the object.

 

3. Which of the following option is true for the given statement?

Statement 1: For gauging the radius, a light source is used with a radius gauge.
Statement 2: The pitch of the threads can be measured by a radius gauge.

  1. Statement 1 is true but statement 2 is false
  2. Statement 2 is true but statement 1 is false
  3. Both statements are false
  4. Both statements are true

Answer.1. Statement 1 is true but statement 2 is false

Explanation:-

For gauging the radius, a light source is used with a radius gauge. Using a radius gage without proper light is nearly useless. If possible, hold gage and workpiece between the light and the eye, but, if this is impossible, at all costs be sure that good strong light shines down on the junction of the radius gage with the radius or fillet being compared.

For determining the pitch of the thread pitch screw gauge is used.

 

4. Which of the following is not a type of radius gauge?

  1. Acrylic
  2. Guitar
  3. Digital
  4. Planer

Answer.4. Planer

Explanation

The different type of radius gauge available are

Arcylic radius gauge:- Radius gauges can be made out of laser-cut acrylic. Acrylic gauges are commonly used for woodworking applications because they do not leave behind dark markings. They are less abrasive than their metal counterparts.

Guitar radius gauge:– A guitar radius gauge is used to compare the string’s height with respect to the fretboard radius.

Digital radius gauge:-  A digital gauge can be used to measure the waviness on a finished surface, the radius of a television tube, the radius of a mould, radius of a machine bent pipe. A digital radius gauge is capable of measuring inside diameters of cylindrical holes, measuring grooves, and measuring diameters of spheres from 100mm to 1000mm.

Ring-bound radius gauge:- A ring bound radius gauge consists of individual multi-function blades held together by a ring. They are multi-functional as each blade is capable of measuring a concave and convex radius.

Note:- Planer gauge is a measuring instrument that is used to measure slot width and setting tool of variable height.

 

5. Which of the following option is incorrect with respect to radius gauges?

  1. Concave radius is an internal radius
  2. Radius gauges are used for final inspection
  3. If the curved surface is external then this radius is known as the female radius
  4. Radius gauges are suitable for both fillet and radius measurement

Answer.3. If the curved surface is external then this radius is known as the female radius

The two types of radius gauges used in workshops are (a) for checking the radius of convex surfaces and (b) for checking concave surfaces. These gauges are pivoted in a holder and used for checking the radius of curvature over a range of 0.6 mm to 25 mm.

A concave radius is an internal radius while a convex radius is the external radius of radius gauge

A gauge used for checking the radius of curvature of concave surfaces is also called a fillet. These gauges consist of a set of plates of different radii. One end of the clamp consists of convex blades and the other end consists of concave blades.

Radius gauges are primarily engineers’ tools used ‘in-process and for ‘final inspection’, when working with materials such as wood, plastic and metal.

 

6. The individual blade of radius gauge is also called as

  1. Leave
  2. Petal
  3. Cutter
  4. Scale

Answer.1. Leave

Explanation:-

The individual strips of metal are known as blades or leaves. They are often made from stainless steel and coated in chrome as this leaves them highly resistant to rust. Every leaves have a different radius, for example with radius intervals of 0.25 mm or 0.5 mm. A radius gauge has a locking device to hold the leaves together in the set. It is also used to lock out a single blade from the tool for use.

 

7. Why a radius is provided at the meeting point of two surfaces?

  1. To reduce material
  2. To avoid collision
  3. To increase stability
  4. To avoid stress concentration

Answer.4. To avoid stress concentration

Explanation

Most all parts and products are designed with rounded edges and with corners filled in.  Stress concentration is defined as high localized stress, located in the small radii and sharp corners that are in a load path.

Providing radii and fillets to corners is highly recommended as they reduce the stress concentrations in the parts and the mold. A fillet radius of at least 0.8 mm should be provided.

 

8. The material used in the radius gauge is/are

  1. Stainless steel
  2. Plastic
  3. Acrylic
  4. All of the above

Answer.1. All of the above

Explanation:-

The material used in the radius gauge is

  1. Stainless steel
  2. Plastic
  3. Acrylic

Stainless steel:- Radius gauges can be made from stainless steel with a satin chrome finish for extra rust resistance. This type of gauge is ideal for checking molds or dies because of the clear markings. Chromium is added to steel to increase corrosion and oxidization resistance. Chromium improves wear and abrasion resistance.

Acrylic:- Radius gauges can be made out of laser-cut acrylic. Acrylic gauges are commonly used for woodworking applications because they do not leave behind dark markings.

Plastic:- Radius gauges can be made from high-grade plastic due to scratch resistance. Plastic gauges are relatively cheap and commonly used for guitar radius gauge production.

Stainless steel blades with a satin chrome finish are advised because of the extra smooth finish to the radius.

 

9. The application of radius gauge is/are

  1. Pattern Making
  2. Final Inspection
  3. Check imperfection
  4. All of the above

Answer.4. All of the above

Explanation:-

Radius gauges are used to measure existing radii as part of pattern making, precision machining, layout creation, and part inspection.

Pattern Making:- Radius gauges are used in woodworking, particularly in relation to layout and pattern-making applications. An acrylic radius gauge can be used to check the radius of wood that has been turned on a lathe or after rounding edges.

After machining to check for imperfections:- Radius gauges can be used to check that a radius has a regular curvature and does not contain any imperfections. Imperfections such as a bumpy surface or offcuts of metal debris left from machining may indicate that the radius needs further work to match the desired shape.

Inspection of tool and die-cast moulds:- Radius gauges can be used to make sure that die casts (metal moulds) are set up with the correct radius measurement.

Final inspection:- Final inspection refers to gauge used for checking that a finished radius meets the required dimensions. Designs are often ground or buffed to meet the required specification, as identified by how well the gauge fits against the object with no visible gap in-between the two surfaces.

 

10. Which of the following option is true for the given statement?

Statement 1: Radius gauges can be covered in an oil-based spray.
Statement 2: Radius gauge should be covered with a plastic base covering

  1. Statement 1 is true but statement 2 is false
  2. Statement 2 is true but statement 1 is false
  3. Both statements are true
  4. Both statements are false

Answer.3. Both statements are true

Explanation:-

Radius gauges can be covered in an oil-based spray as a preventative measure against rust during storage. If a radius gauge becomes rusty, the folding mechanism may seize up. The once precisely machined radius may develop irregularities because of corrosion.

Radius gauge blades with five measuring surfaces are often bought in assortments. Be sure to use the plastic sleeve casing which allows neat and orderly storage.

 

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