Levelling A & B

Question 1

Flat

Answer 1

• to put on the same plane

- not always level

Question 2

Level

Answer 2

-to put on the same plane as the horizon

Question 3

Plumb

Answer 3

• to align perpendicular to the horizon (vertical)

- think of a “plumb bob”

Question 4

Straight

Answer 4

-to be in direct line of (straightness)

Question 5

Square

Answer 5

-something aligned 90 degrees to a reference line

Question 6

Refraction

Answer 6

-light bends differently and travels at different speeds through different materials

Question 7

Diffraction

Answer 7

-shooting close to an edge can cause light to bend

Question 8

Vibration

Answer 8

-can travel through the stand and cause the target to appear blurred

Question 9

Pentaprisms

Answer 9

• 5 sided prism
• regardless of the angle at which the incident ray enters, the refracted Ray leaves at exactly 90 degrees
• the image is not reversed

Question 10

Source of error

Answer 10

-rays can become distorted through a change in temperature, through glass (reflection and refraction)

Question 11

Optical micrometer

Answer 11

• used for precision levelling to .001”
• it’s parallel lens has the ability to bend the light rays and send them out again exactly parallel to the original line of sight.

Question 12

Coincidence level

Answer 12

• used with tilting level for bucking in.

- bubbles fold onto itself

Question 13

Lenses & Prisms

Answer 13

• light can be reflected on a polished surface with the angle of incidence being equal to the angle of reflection
• in thinner material to thicker material the light always refracts towards normal

Question 14

Optical lines of sight

Answer 14

• used instead of a tight wire or string line

- doesn’t sag, get kinked, vibrate

Question 15

Auto-reflection

Answer 15

• auto means mirror (target)
• uses a mirror to send a target image on the crosshairs back to the telescope (2 units working together)
• when you see the reflected image you see the telescopes own crosshairs in the reflected image in the target.
• problems with it are the possible incident rays and the mirror may be tilted.

Question 16

Auto-collimation

Answer 16

• auto means mirror, Collimation means light
• most accurate because it’s aimed at the reflected image of the crosshairs of the telescope itself.
• sees one set of crosshairs when the object of 90 degrees

Question 17

Collimation

Answer 17

• no mirror, two telescopes or one and a Collimator

- projects crosshairs of one telescope onto the crosshairs of the other telescope or Collimator both focused at infinity

Question 18

Collimator

Answer 18

-no eye piece, used for Collimation instead of a second telescope

Question 19

Optical Squares

Answer 19

• mounted on a telescope and establishes a plane perpendicular to the reference line of sight
• the pentaprism is the basis of this tool which allows the line of sight to change 90 degrees

Question 20

Rough alignment scales

Answer 20

• used for levelling floors and setting the grade for drainage pipes.
• accurately read to the closest 1/2 centimetre

Question 21

Obtaining an accurate reading?

Answer 21

-waving the rod and then take the shortest reading

Question 22

Precision scales

Answer 22

-accurate up to .001”

Question 23

Alignment bar

Answer 23

• can measure over 100ft like rollers on a conveyor

- accurate up to .001”

Question 24

Alignment telescope

Answer 24

• most accurate for establishing a straight lie of sight

- can do this by using an optical square, coincidence sliding level and a special plumb aligner bracket

Question 25

Tilting level

Answer 25

- establishes a level plane and is strictly for levelling purposes - for comparing two or more heights at equal distances apart - readjust coincidence level before every move - eye to crosshairs, then the target to crosshairs

Question 26

Survey location ( benchmark)

Answer 26

- to maintain accuracy or minimize inaccuracies the optical tool must be kept at equal distance from the back sight and the foresight - used as a reference point to set the final elevations of installed equipment

Question 27

How to get a straight reference line

Answer 27

-use an alignment telescope with an optical micrometer to level and crane rail

Question 28

Bucking in

Answer 28

- aligning an optical tool onto two targets at the same time. - sight in far target, move laterally to near target or close to, rotate to sight in far target again and repeat. - must use a lateral adjuster with the jig transit

Question 29

Rough levelling

Answer 29

- after setting up tripod tough level the tool by adjusting the fish eye bubble so you are within range of the coincidence level - bubble will move in the direction of your left thumb or towards any clock wise rotation

Question 30

Jig transit

Answer 30

- to align and establish precise vertical planes and plumb lines - used to lay out a reference line at 90 degrees to each other (setting rollers 90 degrees to a reference line in a paper mill

Question 31

To focus

Answer 31

- adjust crosshairs into focus | - then adjust object focus to get scale clearly on crosshairs

Question 32

Transit procedures

Answer 32

-first get your plane then move that line to another vertical plane

Question 33

Theodolites

Answer 33

- can be used to measure angles in horizontal and vertical planes - used to set a conveyor incline

Question 34

Wire alignment

Answer 34

- can get as close as .0001" with headphones and 6 volt battery - you would need a sag chart and the wire's weight and size