Millwright 2Nd Year Levelling And Bore Alignment Part A

Front 1

What 5 basic questions can be answered using optical equipment

Back 1

Is it level

Is it flat

Is it plumb

Is it straight

Is it square

Front 2

___________are used as reference points to set the final elevations of installed machinery

Back 2

Benchmarks are used as reference points to set the final elevations of installed machinery

Front 3

What term means to align to the vertical

Back 3

Plumb

Front 4

When passing from a thinner medium into a thicker medium the light is always refracted _______the normal

Back 4

Towards

Front 5

What is another name for crosshairs

Back 5

Reticle

Front 6

What is designed to be used so that no matter what angle the incident ray enters, the refracted ray leaves at 90 degrees

Back 6

Pentaprism or optical square

Front 7

What is normally used for the rough levelling of optical equipment

Back 7

A fish-eye or circular bubble

Front 8

The purpose of a/an ________is to establish a level plane strictly for levelling procedures

Back 8

Tilting level

Front 9

Optical levelling refers to the process of determining the difference in _______or ________between two points

Back 9

Level, height

Front 10

With the __________attachment, optical instruments can be used to measure with a precision as close as 0.0001 inches, but more commonly down to 0.001 inch (0.02 mm)

Back 10

Optical micrometer

Front 11

All optical levelling equipment is basically composed of a telescope with a spirit level, attached in such a manner that when the spirit level is centered, the line of sight through the telescope is ____________.

Back 11

Horizontal

Front 12

To maintain accuracy, it is important to keep the ___________an equal distance from the backsight and the foresight

Back 12

Instrument

Front 13

Auto-collimation is similar to auto-reflection, but is more __________

Back 13

Accurate

Front 14

Aim

Back 14

To point the telescope in the direction of a target

Front 15

Auto-collimation

Back 15

The act of looking through a telescope at a mirror target and viewing the reflection of the telescopes crosshairs

Front 16

Auto-reflection

Back 16

The act of looking through a telescope at a mirror target and viewing the reflection of a target mounted on the end of the telescope

Front 17

Backsight

Back 17

Normally, the reading that is first taken after setting up an optical instrument to shoot a level. For a backsight to be useful it must be referenced to a known elevation (usually a benchmark. A backsight is usually added to a known elevation to obtain the height of the instrument

Front 18

Buck-in

Back 18

To place an instrument so that the line of sight satisfies two requirements (lines up with two targets) bucking in is usually accomplished through trial and error

Front 19

Collimate

Back 19

A) to bring together. In optical tooling , the light rays of an image are brought into line (collimated) on the crosshairs

B)to adjust accurately the line of sight of a telescope

Front 20

Collimation

Back 20

The process of illuminating one set of crosshairs and projecting that image to be viewed through a second telescope. The telescopes are said to be collimated when only one set of crosshairs is visible in the viewfinder

Front 21

Datum points/lines

Back 21

Known points from which measurements can be taken.

Datum points/lines are needed to determine elevations and horizontal positioning of equipment

Front 22

Elevation

Back 22

The direction of a line of sight in the vertical plane. Means the same as level (when working a level) or height (as in height of the machine)

Front 23

Focus

Back 23

To adjust the optical parts until a sharp image is seen

Front 24

Foresight

Back 24

A sight is taken to a location in order to determine its elevation. The foresight elevation is compared to the backsight elevation to determine its elevation. The foresight is usually subtracted from the height of the instrument to obtain a new unknown elevation

Front 25

Height of instrument

Back 25

The elevation of the optical line of sight. It is normally referenced to the benchmark

Front 26

Horizontal

Back 26

Perpendicular to the direction of gravity (horizon)

Front 27

Objective lens

Back 27

The lens at the front of the telescope nearest to the object sighted

Front 28

Parallax

Back 28

The apparent change in the relative position of objects when sighting through the telescope. Two people view different relative positions of sighted objects when viewing through a telescope. Correcting for parallax is accomplished by shifting the eye slightly to the side and adjusting the focus until there is no more apparent movement of the sighted object

Front 29

Plumb

Back 29

To align to the vertical

Front 30

Reference line

Back 30

A line of sight from which measurements are made

Front 31

Reticle

Back 31

The crosshairs seen when viewing through a telescope

Front 32

Vertical

Back 32

In the direction of gravity

Front 33

Sighting block or plate

Back 33

A special plate designed to reduce reflection when shooting a sight through a restricted opening

Front 34

Turning point

Back 34

A temporary point whose elevation is determined during the process of levelling. Normally, the foresight is a turning point when taking a series of readings, since it becomes the backsight for the next set. The turning point serves as a reference point when moving a level