Metrology 150404a 150404b 150404c Flashcards
The total deviation from basic size is called,
Tolerance
The difference between the upper limit of a shaft and the lower limit of a whole is called,
Allowance
Largest and smallest permissible size of a dimension is called,
Limits of size
The dimension from which the limits of size are derived by the application of Tolerance is called,
Basic size
The type of fit resulting when the limits given to the meeting parts will permit either an interference or a clearance fit is called
Transition fit
The most common system of limits and fits in North America.
Hole basis system
The size used for reference purposes is
Nominal size
The class of fit of those listed below that has the largest tolerance
Rc2
Rc4
Rc6
RC8
RC8
Which grade of Gage blocks is used for the shop floor inspections and set up?
Grade A S - 1
If producing a hole with a diameter of 2.5 in plus or minus 2 thou what would be the limits of size for a no-go plug gauge class y?
2.502 - 2.50188
To accurately position a workpiece in a repeatable manner using the 3-2-1 rule how many datum points are required?
6
Which tools are used as a reference to calibrate a ring gauge?
Gauge blocks and precision rollers
Quality control can be broken into which two groups?
Measuring and gauging
Three grades of Gage blocks and their applications
Grade 0 inspection standard
Grade AS-1 used in shops for parts set up and inspection
Grade AS2 shops looking for cheaper Gage blocks with tolerance is higher than AS1
Why use wear blocks?
Protect your gauge blocks from damage and abrasion
What materials are Gage Blocks made from?
Hardened steel ceramic and carbide
Hardened steel is cheapest ceramic and carbide last longer but cost more
Define limits of size
Maximum and minimum the sizes are allowed specified on the print. Don’t have to calculate, use sizes on the drawing.
Define fit
How the meeting parts fit together either clearance interference or transition
Define tolerance
Permitted variation in a part size the difference between the upper and lower limits of size the total amount size is permitted to vary
Define allowance
Intentional difference in size of mating Parts at their MMC. To calculate, subtract largest shaft from smallest hole
Define datum
Where most points are measured from the zero point
Define datum simulator
Simulated datum is established from a design datum
Two types of error in micrometre threads?
Periodic error and Progressive error
Two types of error in dial indicators?
Repetition error and Progressive error
Types of dial indicators?
Type a standard
Type b perpendicular
Type c Universal
Dials are meant for repeatability not accuracy
Define roughness width cutoff
Greatest spaces between adjacent grooves when measuring roughness height
Difference between waviness and roughness?
Widely spaced marks caused by vibration and chatter, heat treatment, and deflection
Closely spaced marks caused by the cutting tool
The difference between balanced and continuous reading dial indicators?
Continuous are numbered one through 360 degrees, balanced reads in both directions from zero
Three types of precision squares?
Blade (try square), cylinder, block.
Name to master squares
Cylinder and block, AA grade
What is the 3-2-1 rule?
Restricting and securing peace in three axes in One Direction
Two types of air gauges?
Column, pressure
What are the 7 parts of a dial indicator?
Contact point Spindle Rack Spring Rack Hair spring Bezel Gear train
What are the two types of optical comparators?
Shadowgraph, gears in a watch
Mechanical Optical, Reed type
What is the advantage of using a fixed gauge for inspection instead of a micrometre?
You eliminate the stupidity of the operator.
How does comparison measurement differ from other types of measurement?
Comparison determines how much the actual size of a part differs from the size of a standard
What is the difference between a continuous reading dial indicator and the universal dial test indicator?
Continuous reads from 0 to 360 degrees, Universal reads both directions from zero
An air gauge uses air pressure to compare the diameter of a bore with what?
Master Ring gauge
What is a micro inch? Micrometre?
.000001
.0000001
What is lay?
The direction of the roughness pattern
What is Centerline average?
The average height of the Peaks and valleys on the surface pattern
What is the term for the joining of Gage blocks?
Wringing
What takes the backlash out of the gear train on a dial indicator?
A hair spring
What is the most common contact point for dial indicators?
The half sphere
What would you use to measure the included angle of a high speed steel lathe tool for cutting an Acme thread, 29.5 degrees?
A protractor screen
What is an optical flat used for?
Flatness, parallelism, and size
What do you call the patterns of dark bands stretching across the optical flat?
Fringe patterns
What do you call the pattern of Shadows that the coordinate measuring system relies on?
Moire Fringe
What three abbreviations are Centerline average known as?
CLA, Ra, AA
What are the two ways of checking for lack of flatness or parallelism on a micrometres anvils?
An optical flat or a Precision ball
What is the result of an incorrectly set up coordinate system?
Provides defective measurements.
