7.3 Sippo Questions Flashcards
When using a hacksaw how many teeth must be in contact with the metal being cut at any on time
More than 1
What technique is used to produce a good cut with a hacksaw
Start by holding the saw at an angle
Forward stroke under pressure
Return stroke without pressure
Near end before material separates reduce pressure on saw
What has to be remembered when fitting normal hacksaw blades and junior hacksaw blades
On normal - teeth must point in cutting direction
Junior - teeth facing towards handle
What prevents the hacksaw blade from binding in the material when being used
As it cuts into material the slot it created must be greater than the blade thickness. - must cut required clearance.
By:
Teeth are set
Blade is waved
What is meant by a double cut file
Has two sets of teeth overlaid at 45degrees to each other for faster material removal
Apart from double cut what are the other cuts of file
Single cut - for soft material and fine finishes
Rasp cut - wood and leather
Curved tooth - dreadnought for smooth finished on aluminium or removing large amounts of material on soft materials
What safety precautions must be observed when using files
Always use a handle on a file
Where should a bench vice be in conjunction to your body
5-8 cm below you elbow
What is the purpose of draw filling
For final finish
Usually used on parts that are relatively long
Used to get a fine surface to prevent crack growth
What is the purpose of flutes in a drill
Helical grooves provide cutting lips which permit the removal of chips and allow cutting fluid to reach the cutting lips
Where is the body of a drill bit
The part between the point and the shank. Including spiral flutes, lands and the margin
Why is it important for the body of a drill bit to be slightly tapered
Means it is fractionally larger in diameter at the tip then at the shank, therefore causing it to bore a hole with clearance to prevent the drill from binding
What type of drill best lends itself to sheet metal work
Jobber drill
How is a taper shank drill fitted to a drill motor
At the end of taper shank there is a tongue, called tang. And when taper shank is fitted into the socket spindle the tang engages in a slot
What is the drill point angle for general purpose drilling
Should be sharpened to a cone of 118 degrees (lip angle 59degrees)
What are the drill point angles for hard materials and soft materials,
Angles of 140 degrees are for hard materials
Angles of 80degrees are for soft materials
What does a pillar drill make possible
Precision drill work. As no play I’m spindle, bearing or chuck. And clamped
What are the advatange of using pneumatic drills in aviation
Less hazardous than having electrical cables on a crowded plane
Control offered by air drills. - varying trigger
What may be used to prevent a drill from penetrating too far into a structure when drilling
Drill stop
What are the three probable causes of a drill that won’t feed into the material
Drill blunt
insufficient drill cutting clearance
Drill too large (pilot hole needed)
Why does drilling of thin plate require special care
The drill point often breaks through before the drill has cut its full diameter
What clamping devices may be used when hand drilling
Angle vices, pin vices, hand vices
What is the purpose of a drill guide
The hand held drill guides keeps the drill 90 degrees to the skin surfaces.
How is a hole finder used
When replacing an old skin with a new one. If no pilot holes drilled in new skin.
The finder resembles a clamp that slips over the new skin and on its underside is a pin that exactly fits through the hole in structure. This guides the drill in making a new hole in new skin that aligns with the old one.
What’s the advantage if using a drill agent
Improves hole life
Hole tolerance hole finish
(Shown in AMM if allows and what one)
What should be taken into account when drilling hard materials in comparison to soft materials
Drill speeds (revolutions per minute)
Hard materials should be drilled slower
What are the two systems of fits
Hole base and shaft base
Describe what reaming is
Process which a fluted tool is used to enlarge a drilled hole.
A hole that is to be reamed is drilled 1/32 inch under the finished hole size
How could you determine wether or not a reamer will produce a hole of the correct tolerance
Test it in scrap materials
Reamer generally produce a hole that is 0.001 inch larger than exact size of reamer
What are the common factors that affect the size of the reamed hole
Pilot hole
Hardiness of material
Amount of material being removed by reamer
Speed of reamer
Rate of feed (pressure)
Sharpness of reamer
Amount or type of lubricant
How many different types of flute are there on a reamer and what are they
Straight and spiral flutes
What are the benefits of using a pilot check reamer
Gives accurate lead into a drilled hole and superior finish
Expansion hand reamers may be used on high tolerance aircraft parts instead of solid reamers
True or False
False as this could cause the danger of oversized holes
What are likely causes of oversized reamed holes
Hand expansion reamers
Inadequate work support
Worm guide bushings
Bent reamer shank
Trying to straighten the reamer if bent
In relation to countersinking what is knife edging
Sheet metal should not be countersunk all the way through else knife edging which could result in cracking (see SRM for minimum sheet thickness)
What countersink angles are likely to be encountered in aviation
82, 100,120
With 100 being the most common
What’s the purpose of a microstop countersink tool
Fitted with removable cutter and pilot.
Controls countersink depth and keeps work perpendicular to work surfaces
What device is used to countersink inaccessible holes
Back countersinking
What is spot facing
Used for cutting a flat area or seat for a bolt head or nut on a contoured or uneven surface
What situations should you allow for extra depth when adjusting a microstop countersink
Because countersinking is done through skin tape or protective spray coating. Allow for added thickness
What are the two series of an ISO thread form
United national fine UNF
United national coarse UNC
What was a commonly used thread form
Whitworth thread form
What is the thread form used in electrical fitting and scientific apparatus
British association thread
What does a regular hand tap set consist of
Taper, intermediate and bottoming tap
What is the essential element for successful tapping
Holes are the correct size and condition
When using torque wrenches what has to be taken into consideration.
If the threads are wet or dry
The AMM stipulates the torque loading for both
Does a wet or dry thread require more torque loading
A wet thread requires more torque to be applied
If using an extension with a torque wrench what do you have to remember
It’s length must be taken into consideration
Because torque values on a deflecting beam or torsion will be taken from the centre of the square drive
What is the benefit of synthetic oil over mineral oil
Synthetic oils are manufactured by chemical reactions and can produce consistent quality.
Whereas mineral oils can contain some impurities, less pure and less thermally stable
What is the problem with putting a synthetic oil in a mineral system and visa versa
Lubricants should not be mixed.
Putting the wrong lubricant can break down a seal, destroying its effectiveness.
Therefore should always be clearly marked and check AMM
How is a micrometer tested during routine calibration
Using a standard gauge block that is manufacturers to a very close tolerance (has calibration itself)
Then gauge block inserted between anvil and spindle - then closed.
Tool then adjusted to zero mark on thimble until exactly coincides with the sleeve datum line
When using a micrometer what should be used to turn the thimble
Ratchet stop
How many different types of measurements can be taken away with a venier calliper and what are they
Imperial and metric
External, internal and depth
What is the most common vernier calliper and what is its range of accuracy
1/20 or 0.05mm
When grinding with an abrasive wheel why should you not grind on the side of the wheel
A groove can form over time, creating a weak point that has in the past led to wheels exploding
What maintence practises occasiaonally need to be performed on punches
Deburring of striking face
