Levelling And Bore Alignment Flashcards
What does Level mean?
To put into the same plane as the horizon
What does Flat mean?
To level but typically on a slope or angle
Ex: incline conveyer
What does plumb mean?
To align perpendicular to the horizontal. (Vertical levelling)
Example: bucket elevator
What does square mean?
Refers to something that is aligned 90 degrees to a reference line
What is an optical tool
Optical tools use and control light rays with various lenses and prisms
What are the (6) advantages of using an optical tool for alignment?
- Does not sag
- Cannot kink
- No tripping hazard
- Remains straight in long distances
- No vibrations
- Accurate within thousandths of an inch
What are the (2) main sources of error with optical lines?
Reflection and refraction can cause the lines of sight to bend producing inaccurate readings.
What are (4) examples of things that would cause problems with optical lines of sight?
- Shooting through heat waves
- Shooting through gas
- Using a sighting block (small opening)
- Shooting near the edge of a hole
What happens when light rays pass from one medium to another? (Example air to glass)
Their direction changes.
What is the “normal” in terms of optical tools
Normal is a line perpendicular to where the two surfaces meet.
What happens when light passes from thinner medium into a thicker medium?
The light is always refracted (bends) toward the normal.
What happens when light passes from a thicker medium into a thinner medium?
The light bends away from the normal.
I’m terms of opticals what does a convex lens do?
•Focusing
•it pulls light rays closer together
In terms of opticals what does a concave lens do?
•disperses
•sends light rays further apart
Explain a prism in terms of optical tools and how they work
Has a glass body with 3 or more optically flat surfaces that are not parallel.
They control the direction of light rays through reaction and reflection.
What is are pentaprisms and what is the advantage to using them?
They are 5 sided prisims
Regardless of the angle at which the rays enter the redacted light leaves at exactly 90 degrees
Due to this the image is NOT reversed.
How does auto reflection and auto collimation work?
Based on the law of light reflection
When a mirror is tilted you can see a reflected image of an object
However when the mirror is perpendicular to your eyes you see yourself.
Explain using auto reflection in optical alignment to turn a line of sight 90 degrees, along with how it works.
A flat target mirror is attached to the side of a jig transit.
The telescope is set on a reference line and the jig is aligned to this sight.
Once the reflected image of the crosshairs is centred the transit is locked and used to sweep a plane 90 to the original reference line.
Why is auto collimation more accurate than auto reflection?
The line of sight of the telescope is aimed at reflected image of the crosshairs of the telescope itself.
How does auto collimation work?
Similar to auto reflection however the mirror is adjusted until the reflected image of the crosshairs falls on themselves.
What is a auto collimation illumination unit?
It is the light source used in auto collimation
It is mounted on the eyepiece end of the telescope. Utilizing a semi transparent mirror to allow the observer to see the crosshairs image on the mirror
What is auto collimation typically used for? (3)
-Testing and adjusting optical instruments and telescopes,
-testing prisms
-positioning machine parts to 90 degree reference line
What is required to use collimation?
Special instruments such as the jig transit telescope square
What is a jig transit telescope square?
A special instrument used in collimation
It is a transit with two telescopes mounted 90 degrees to each other
What is happening when crosshairs are illuminated in collimation?
They project the collimated rays resulting in the image of the crosshairs being projected out of the telescope.
Explain what an optical micrometer is and how it works
-It is an accessory attachment
-The lens is calibrated to a micrometer dial, which measures the amount the light ray is displaced
-as the micro dial is adjusted the crosshairs move down the scale until they are on a reading on the scale.
How accurate are precision targets?
Used with optical micrometers, it can read an accuracy of 0.001”
When used with a vernier scale it can be accurate to 0.01”
Different scales are used for varying distances to make it more accurate
What is a bearing target holder?
It accurately positions targets in the centre of bearing bores. They may have a micrometer in the legs to ease positioning
What is a open alignment target and when is it used?
It is clear with monofilament cross lines, used when a target is required at several positions along a line of sight.
These it is possible to site directly through without distorting
What are mirror targets used for?
To check perpendicularity if a part by auto reflection or auto collimation and to position the part in the line of sight
What is a coincidence striding leve and what’s the accuracy?
Used on an alignment telescope or collimator to establish the tool in a level position
Typically use a coincidence type reading making accuracy within one arc second.
What does a right angle eyepiece do and when is it used?
It is used to make viewing easier for the operator and is used when the telescope is mounted close to the floor or other obstructions.
What is a auto reflection target used for?
Mounted to the end of a telescope it is used to view the reflection of the telescopes own crosshairs when looking at a mirror
Some telescopes have these built in
Explain an optical square
Mounts on the end of an alignment telescope
Establishes a plane perpendicular to the reference line of sight.
It uses a pentaprism which allows the line of sight to change 90 degrees
What is the benefits to using an optical square?
No adjustments have to be made to set the right angle.
What are potable instrument stands in optical levelling normally made from and what is a disadvantage to this?
Commonly Mande with aluminum for ease of weight however makes them susceptible to thermal growth
The person mechanical lateral adjuster does NOT mount to these types of stands.
What is a trivet?
A special instrument stand in optical leveling for supporting instruments near the floor or any position where the line of sight is low.
Have a standard thread head for mourning lateral adjusters
What is a lateral adjuster?
An attachment that goes between the optical levelling stands and tools to allow for precision adjustments.
(Similar to crossfeed on a lathe)
How does a lateral adjuster mount to instrument stands?
Standard threads (screw on)
Where are inaccuracies normally developed with rough alignment scales?
Normally from not holding the rod truly vertical
Where are rough alignment scales normally used and what’s their accuracy?
General work such as levelling floors
Accurately read to .5 cm but can be estimated down to 1mm.
What’s the accuracy of a rough alignment scale when combined with an optical micrometer?
0.01mm
(Hundredths of a mm)
Typically how long is a rough alignment scale?
4 metres
What is the simplest way of obtaining an accurate reading with an alignment scale?
Rocking the rod (waving the rod) on each side of the vertical while it is being read.
The shortest reading is the correct one as it is the most vertical.
What is a rod level?
Consists of a fisheye level mounted at a right angle to a piece of angle iron.
This is held against the rod to ensure it is plumb
How are precision alignment scales in optical levelling normally constructed?
Typically a shorter scale made of hardened tool steel anywhere from 3-40” in length.
What is the accuracy of a precision alignment scale in optical leveling?
When temperatures are 20C or 68F they are accurate within 0.001”
What is the alignment bar system in optical levelling?
Measures large linear distances vertically or horizontally to over 100ft. Iconostasis if a precision track that a carriage with the optical tool rides on.
What is the accuracy of the alignment bar system in optical levelling?
Accurate to 0.001”
What are alignment telescopes commonly used for?
To establish a straight reference line of sight. However with the correct attachment they have various uses.
What attachment is needed with an alignment level to establish a level reference line?
Coincidence striding level
What attachment is needed with an alignment level to establish a vertical line
Special plumb aligned bracket
What attachment is needed with an alignment level to establish a plane perpendicular to a reference line?
An optical square
All optical instruments use ____________ for viewing the target and all work on the same principle.
A telescope
The optical telescope must be equipped with what for precision work?
Optical micrometer
What are tilting levels used for in optical alignment?
To establish a level plane, they have to ability to tilt on their horizontal axis to adjust for level.
What is a line of sight in optical levelling?
Is an extension of the optical axis established between the telescope and the target.
What is a plumb aligned bracket in optical levelling?
A special jig that allows the telescope to be set up to establish a vertical plumb line.
What are the (4) main producers for establishing a plane perpendicular to a reference line?
- Optical square
- Auto reflection
- Auto collimation
- Collimation
What is the purpose of a jig transit in optical levelling?
To align and establish precise vertical planes and plumb lines.
What does a Theodolite measure?
Angles
What are the five optical questions?
- Is it level
- Is it flat
- Is it plumb
- Is it straight
- Is it square
What can be used to answer all 5 optical questions?
Jig transit
Before use what must be done with a jig transit?
It must be levelled, aligned, and checked for error.
What is “bucking in” in terms of optical alignment?
The process of aligning an optical tool into two targets at the same time.
What are reference plugs normally made of?
Brass
How can you check the accuracy of a jig transit or theodolite?
Using a heavy plumb bob and oil
What does oil do in use with a plumb bob?
It helps stabilize the wire by limiting movement.
Which is more accurate for levelling a jug transit telescope or an alignment telescope, and why?
Alignment telescope
- due to the longer length of the telescope.
What can theodolites be used for?
Measuring angles on horizontal and vertical plane.
What is the main disadvantage to using a theodolite
They can be difficult to set up and tend to be more complicated than tilting levels
The measurement of horizontal and vertical angles is unique to ____________
Theodolites
How accurate is wire alignment when done properly?
Can be as close to 0.0001”
What is the (3) benefits of using wire alignment?
- Simplicity
- Ease of setup
- Cost
What is the wire commonly used in wire alignment?
Piano wire
What is normally added to a plumb bob to add drag?
Wings
What is the main disadvantage of using the horizontal wire alignment method?
Gravity causes sag
______________ are used as reference points to set the final elevations of installed machinery
Bench marks
What term means align to the vertical?
Plumb
When passing from thinner to thicker material light is always refracted __________ the normal
Towards
What is another name for crosshairs?
Reticle
What is designed to be used so that no matter what angle the incident ray enters the refracted ray leaves at 90 degrees? (2)
Pentaprism or optical square
What is normally used to rough level optical equipment? (2)
Fish eye or circular bubble
The purpose of a/an ______________ is to establish a level plane strictly for levelling procedures
Tilting level
Optical levelling refers to the process of determining the difference in __________ or ___________ between two points
Level or height
With the ____________ attachment optical instruments can be used to measure with precision as close as 0.0001 inches but more commonly down to 0.001inch (0.02mm)
Optical micrometer
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 centred the line of sight through the telescope is ______________
Horizontal
To maintain accuracy it is important to keep the ______________ an equal distance from the back sight and the foresight
Instrument
Auto collimation is similar to auto reflection but is more ___________
Accurate
What does levelling machine bases do? (2)
Reduces machine strain
Provides opportunities to pre align shafted at coupling locations before grout is poured
What are the 3 main groups of laser levels?
-high accuracy, long distance
-high accuracy, short distance
- construction grade
What is the limitation (accuracy) of construction grade lasers?
1/4” over 100ft
What is laser accuracy based on?
Smallest accurate reading at the greatest distance away from the laser.
What are the (7) laser options with programmed lasers?
- Shaft alignment horizontal
- Shaft alignment vertical
- Single flat plane (straightness)
- Perpendicularity (90 degrees to a levelled surface)
- Perpendicularity with a slight angle deviation
- Parallelism
- Spindle alignment
What is the (2) benefits of using a high accuracy short distance laser
-cost (much cheaper than long distance)
-very accurate
What are the 3 key parts to a high accuracy short distance laser?
- Laser
- Reviver
- Mounting hardware
What are laser plumb bobs made from
Brass
Where are pocket sized laser levels used?
Where there is insufficient space to create a reference line.
What are laser angle generators used for?
To quickly measure slopes and angles
What are laser glasses?
Used to improve the visibility of a laser dot
(They do NOT give eye protection)
Who should calibrate a laser?
Only an authorized dealer
How can combination laser beams and vial levels be checked for accuracy?
By reversing the level end for end and checking the position of the bubble
What is a bench mark?
A fixed reference point which all measurements are taken
What does optical levelling refer to?
Determining the difference in level or height between two points
Into which safety classification do laser tools fall into
Calss 2 lasers with max output less than 1mw
Optical levelling equipment is composed of a ____________ with a ___________ attached
Telescope with a spirit level
What are the (4) optical instruments used for levelling equipment?
- Alignment telescope
- Theodolite
- Tilting level
- Jig transit
A period of ________ the instrument is required to ensure accurate readings
Acclimatizing
Due to temperature changes
To maintain accuracy the optical took must be kept close to an equal distance from the ____________ and the ___________ to reduce error
Back sight and foresight
The tilting level has a rough alignment ______________ that must be levelled before adjusting the confidence bubble
Circular vial (fish eye)
A _____________ is used to identify thermal growth in the horizontal planes
Jig transit
