M7.3 Flashcards
How do you attempt to reduce parallax error?
Your observing eye should be as near as possible
Why should you never use a lead pencil on titanium?
Because the carbon can infuse the metal and cause cracking
Why cant you use normal lead pencil on aluminium alloy?
Because it introduces graphite into the material causing corrosion
What is the angle of a centre punch?
60 degrees
When sawing how many teeth should be in contact with the material?
More than one
What is the pitch of a saw bade?
Tooth to tooth
What are the three types of saw blades?
- coarse
- medium
- fine
Why is the slot of a saw blade thicker than the blade?
To stop it from binding (known as clearance or kerf)
What are the four types of files?
-single cut (smooth)
-double cut (second)
-rasp cut (bastard)
-dreadnought (rough)
(Grades of cut)
What is pinning of a file?
Clogging of the teeth
What are drills made it of?
Carbon steel or high speed steel
What is the lip angle of a drill bit?
Half the included angle
What is the included angle of a drill bit?
118 degrees
What is the taper called on taper shank drill?
Morse taper
For very hard metals what is the included angle of the drill?
140 degrees
What can the included angle be dropped to for soft metals?
40 degrees
What is the most common drill for sheet metal?
Pneumatic or air drill
What is another name for the flat offset driving head?
Pork chop
What does a drill stop do?
Regulates the hole depth and cushions the break through
What is the job of the drill guide?
It keeps the drill at 90 degrees to the skin surface
What is boelube?
Is an agent for drilling aluminium, magnesium, steel, titanium
How long after using should boelube be removed?
Within 48 hours
What is tolerance?
The difference between the maximum and minimum sizes
What are the three types of fit?
- clearance fit
- interference fit
- transition fit
What are the limits called on a tolerance?
Upper and lower limits
What are the two types of system fits?
- hole basis system (hole size is fixed and shift varied)
- shaft basis system (shaft size is fixed and the hole is varied)
What do reamers do?
I larger the hole and helps Improve the quality
What are reamers made from?
Carbon tool steel or high-speed steel
Why should you always rotate a reamer in the cutting direction?
To avoid chipping as it is very brittle
What is the main advantage of a left-hand twist reamer over a right-hand?
It wont pull itself into the hole
What is chatter?
When the tool or work has been vibrating during cutting which produces uneven cuts
What are the two types of reamers?
Hand and machine reamers
How do you adjust the expansion hand reamer?
By tightening a taper screw into the opening
What is reaming speeds?
The speed of chip removal
What are the angles of countersink?
- 82
- 100 (most popular)
- 120
What does a micro stop countersink do?
Controls the depth of the countersink cut and helps keep it perpendicular
Why are back countersinking tools used?
When countersinking holes that are inaccessible
What is spotfacing?
When you need to cut a flat are into an uneven surface
What is the angle for a ISO metric / unified imperial Series thread?
60 degrees
What is the angle for a American national thread and DIN metric thread?
60 degrees
What is the angle for whitworth thread?
55 degrees
What is the angle for British association thread?
47.5 degrees
What is the job of the stock in hand threading?
To hold and tun the threading die
What is the job of a die in hand threading?
To cut the thread onto the tube
What is the tap wrench used for?
Holding the tap
What are hand taps used for?
To cut the tread into the hole
What are the three types of taps?
- taper (1)
- intermediate (2)
- bottoming (3)
What is torque?
The amount of rotational force applied when tightening a fastener
What is used to prevent over tightening a fastener?
A torque wrench
What are the three types of torque wrench?
- deflecting beam (uses a pointer)
- torsion bar (uses a dial)
- toggle bar (uses pre-sett torque)
What effects does lubrication have on a torque wrench?
It’s gives a false torque reading and. Normally over tightens
How often should torque wrenches be calibrated?
Depending on use every week, 6 months, annually
How do you check or readjust a micrometer?
By using a standard or gauge block
What is the job of a three point internal micrometer?
To give more accuracy to internal measurements
What is the job of depth micrometer?
To measure the depth relative to the base plate
What are most abrasive wheels made out of?
Silicon carbide
What are mineral oils derived from?
Crude oil (extracted from underground)
What are synthetic derived from?
Chemical reaction
Can you mix lubricants?
No
Where should lubricants be stored?
In lockers and areas to minimise fire because they’re volatile
How is an aircraft automatically grounded?
Via the nose landing gear
How long are the cables on a bonding testing kit?
60 and 6 feet
On a bond testing kit where should the 60 foot cable go?
To main earth (bond datum point)
How do you test for a concealed break in a cable?
By using a continuity tester
