GAUGE AND TYPES OF GAUGES-FITTER ONLINE NOTE

 TYPES OF GAUGE

1- Limit gauge

2- Ring gauge

3- Snap gauge

4- Plug gauge

5- Filler gauge

6- Screw gauge

7- Screw pitch gauge

8- Radius gauge and Fillet gauge

9- Wire gauge

10- Fishtail gauge

11- Taper ring gauge.

12- Adjustable caliper gauge.

13- Progressive plug gauge.

1- Limit gauge:-

i)- Components manufactured using mass production method are checked only to ensure that the sizes are with in the precribed limits.

ii)- The most economical method of checking such components is by using limit gauges.

iii)- These gauge are used in inspection because the provide a quick means of checking.

2- Ring gauge:-

i)- These are used to check the outside diameter of the work pieces.

ii)- Separate gauge are used for checking GO and NO-GO size.

iii)- The NO-GO gauge is identified bu an annular grooves, cut on the knurled surface.

3- Snap gauge:-

i)- Snap gauge are used as a quick means for checking sizes within certain limits by comparing the size of the parts with the opening of the gauge.

4- Plug gauge:-

i)- Components manufactured using mass production method are checked only to ensure that the sizes are with in the prescribed limits.

ii)- The most economical method of checking such components is by using limits gauges.

iii)- These gauge are used in inspection because they provide a quicky means of checking.

iv)- These gauge have two ends namely GO and NO-GO.

v)- The go end of the gauge must go in to the feature of the components and the NO-GO end must not go in to the same feature.

vi)- The GO is made longer then the NO-GO end for easy identification.

5- Filler gauge:-

i)- These are thin steel blades hardened and ground to various size.

ii)- They consist of a number of small lengths of steel of different thickness with measurements marked on each piece.

iii)- Used for checking the clearance between two mating parts.

iv)- Vanes are from 0.03 to 1mm thickness.

6- Screw gauge:-

ii)- The thread profile on each blade is cut for about 25 mm to 30 mm . 

ii)- The pitch of the blade is stamped on each blade . 

iii)- The standard and range of pitches are marked on the case . 

iv)- For obtaining accurate checking while using the screw pitch gauge , the full length of the blade should be placed on the threads 

7- Screw pitch gauge

i- A Screw pitch gauge A screw pitch gauge is used to determine the pitch of a thread. 

ii- It is also used to compare the profile of threads. 

Constructional features of gauge

1- Pitch gauges are available with a number of blades assembled as a set. 

2-  Each blade is meant for checking a particular standard thread pitch. 

3- The blades are made of thin spring steel sheets, and are hardened. 

4- Some screw pitch gauge sets will have blades provided for checking British standard thread (BSW, BSF etc.) at one end and the metric standard at the other end

8- Radius and fillet gauges 

1- Components are machined to have curved formation on the edges or at the junction of two steps. They are called radius and fillets. 

2- The size of the radius and fillet is normally provided on a drawing. 

3- The gauges used to check the radius formed on the edges of diameters are fillet gauges.

4- The gauges used to check the fillets are called radius gauges. 

5-  They are made of hardened sheet metal each to a precise radius. 

6-  They are used to check the radii by comparing the radius on a part with the radius of the gauge. 

7-  Figure shows the application of a fillet gauge to check the radius formed externally.

8- Figure shows the application of a radius gauge to check the fillet formed on a turned components.

The other typical applications are

9-  Checking the corner radius of a part being filed to shape. 

10- The radius and fillet gauges are available in sets of several blades which fold into a holder when not in use.

11- Some sets have provision to check the radius and fillet on each blade.

12- And some sets have separate sets of blades to check the radius and fillet.

13-  Each blade can be swung out of the holder separately, and has its size engraved on it. 

14-  Fillet gauges are available in sets to check the radii and fillets from. 

1 to 7 mm in steps of 0.5 mm 

7.5 to 15 mm in steps of 0.5 mm 

15.5 to 25 mm in steps 0.5 mm 

15- Individual gauges are also available.

16- They usually have internal and external radii on each gauge and are made in sizes from 1 to 100 mm in steps of 1 mm. 

17- Before using the radius gauge 

i- Check that it is clean and undamaged. 

ii- Remove burrs from the workpiece. 

iii- Select the leaf of the gauge from the set corresponding. 

iv- To the radius to be checked.

18- Figure shows that the radius of the fillet and that of the external radius are smaller than the gauge. 

19- Try a smaller gauge to determine the radius dimension. 

20- File or machine the work piece if it has to be of the radius of the gauge.

21- The radius of the fillet and that of the external radius are larger than the gauge. 

22-  Try a larger gauge if you need to find the radius dimension. 

23- If the work piece has to be of the radius of the gauge you may have to reject the work piece.

9- Wire gauge:-

i)- The standard wire tool to measure the predefined wire diameter.

ii)- It consist of oblong plate having holes of different size to receive different size wires. Each hole is stamped with a number which define the holes and wire size. 

iii)- This stamped number starts from 1 to 80. O This wire gauge also available in circular shape.

10- Fishtail gauge:-

11- Taper ring gauge:-

i)- These gauges are used to check both the accuracy and the outside diameter of a taper.

ii)- Ring gauge often have a scribed line or step ground on the small end to indicate the GO and NO-GO dimension .

12- Adjustable caliper gauge:-

i)- These gauge are generally 'C' shaped and are adjustable to the maximum and minimum limits of the part being checked.

ii)- When in used the work should side into the GO anvil but not in to NO-GO anvil.

iii)- Snap gauge and adjustable caliper gauges can be used for checking external sizes in any place along the length of a work.

13- Progressive plug gauge:-

i)- These plug gauge are used for checking the diameter of a straight hole.

ii)- The GO gauge check the lower limit of the hole and the NO-GO gauge checks the upper limit.