M7 Maintenance Practices 7.3 Flashcards
Are rulers used for precision work
No due to parallax error
What is a radius gauge used for
To measure internal and external radii
What type of pencil should not be used on titanium
Lead
Why should scribe lines only be cut lines
Because scribe lines damage material
What is a ball gauge used for
To measure the bore of a hole
How are hammers classified
By type and weight with out the handle
What is the face of the hammer
The hitting surface
What is the cheek of the hammer
The side like the cheek
What is a copper Hyde face hammer used for
Shaping metal with out marking material
If removing a rivet what size should the pin punch be
Same diameter as the shank of the rivet
What are centre punch angles
60° and 90°
What is a 60° centre punch used for
Light work
What is a 90° centre punch used for
General
What way does a standard hack saw blades teeth face
Away from the handle
What way does a junior hack saws teeth face
Towards the handle
What is the offsetting of the teeth of a hack saw blade called
The KERF and is used to prevent jamming during use
How many teeth do corse hack saw blades have
14 tpi and used for cutting sort material
How many teeth do medium hack saw blades have
22 teeth
How many teeth do fine hack saw blades have
32 teeth and used for cutting hard material
How many teeth should be in contact with work at all times
2
What type of work would a single cut file be used for
Soft material
What type of work would a double cut file be used for
General
What type of work would a dreadnaught file be used for
Heavy work
What type of work would a rasp file be used for
Wood/leather or soft material
Why is draw filing used
To obtain a very fine finish
What is the point of a drill
The lip or cutting edge
What is the land of a drill
Plain point between flutes
What is the shank of a drill
The portion that goes into the chuck and where all information is kept
What drills are most common
Jobber drills
What type of drills are used in areas with limited access
Extension drills and they should always be used with a guard
What is the standard lip angle of a drill
59° or 118° inclusive
For drills over 3” diameter what should drill speed be limited to
6000rpm
When should flat offset or port chop drill be used
Hard to reach area
When tightening a drill in a chuck how many holes at least should be tightened
At least 2
Why is de burring used
To eliminate stress raisers
When drilling hard material such as titanium, what rules must be followed
Low speed high feed
What are “Limits”
The maximum and minimum permanent sizes of a component
What is “Tolerance”
The difference between the maximum and the minimum
What is a clearance fit
It will go straight in
What is an interference fit
Pin bigger than hole
What is transition fit
Can either be too big or too small
What are the two system of fits
- Hole basis system
- Shaft basis system
Which of the two system of fits are preferred
Hole basis system
In relation to swarf, how does a right hand reamer work
The same as a regular drill. The swarf comes out of the flutes backwards
With regards to swarf, how does a left hand reamer work
Pushes swarf forward into the work
What is important face to remember about reaming
The reamer should always be rotated in the direction of the cut even when removing the reamer from the work
When would an expanding reamer be used
Only when a normal reamer of the same size is unavailable
How are metric and imperial reamers graded
Metric - 1:50
Imperial - 1:48
What is important to remember about the metric reamer
Size written on the shank but refers to the smallest part of the taper
What is important to remember about the imperial reamer
Details written on the shank but refers to the largest diameter of the taper
What is the regular countersink size
100°
Why is countersinking used
For aerodynamic smoothness
What is the disadvantage of the plain and pilot countersink tool
No depth guidance
What is the preferred method of countersinking
By using a micro stop
What are UNF threads
60°
What are BA threads
47.5°
Anything below 1/4” given numbers 0-12
How are screws threads per inch measured
A screw pitch gauge
When cutting rods or dowels to fit into a hole should it be cut to major or minor diameter of the thread
Major
How many types of tap are normally made for each size
3
Taper tap
Second tap
Plug tap
What’s the disadvantage of the deflecting beam torque wrench
Parallax error - can’t really see the torque
What is the equation for scale reading
Specific torque x L
LxA
When are pre loaded indicating torque washers used
Restricted access, they are also supplied in different collars
What is the lead of a metric micrometer
0.5mm one complete rotation
What is the lead of an imperial micrometer
1/10” one complete rotation
Why should you never use the side of an abrasive wheel
To prevent weakening
When setting up a tool holder on an abrasive wheel, how big should the gap be between the tool and the wheel
As small as possible
Why is lubrication generally used
- To prevent heat build up
- improve efficiency
- prolong component life
When is a milivolt drop test carried out
To measure resistance in a poor connection or loose terminal
