Shop/ PD Flashcards
Minimum OG length
Minimum 2x offset, 3x preferred
What is a constant current welding machine ?
SMAW OR GTAW
DCEP
Reverse Polarity - direct current electrode positive, slower weld speed, deeper penetration, good for heavy gauge
DCEN
Straight Polarity - faster, shallow penetration, good for light metal
Double hem Allowance
2W minus 1/16
Groove seam allowance
3W (1.5for each side **)
Difference between hot rolled and cold rolled steel?
Hot rolled is lower grade and not as hard as cold rolled
How is copper gauged
Oz per square foot
Mild steel has a _____ carbon content?
Low
10gauge metal is how thick?
1/8th
16 gauge metal is ?
1/6 thick ( 6 gauges is half thickness)
(Not sure on this one) need to be confirmed
Type of aluminum most used in architectural sheet metal work is called?
Half hard
Ferrous metals are gauged using ?
Standard gauge
Most aluminum has what type of finish?
Mill
Metals thicker than 1/4 are called?
Plate
Process that builds natural oxide on aluminum?
Anodizing
Copper is used for intricate work because?
It’s very malleable
A metal that is used to strengthen steel? Chemically non reactive and not affected by most acids
Molybdenum
Most commonly used screen in sheet metal shop?
Hardware cloth (bird screen)
To prevent exposure or contact with DC current when using plasma table, operator must make sure that ?
Nozzle in place
Safety sensor in place
Good rule of thumb, choose a machine class that is how many times your typical cutting thickness
Two times
Plasma nozzles are sized according to?
Amperage
How to find Kerf compensation values?
Trial and error
Best indicator of worn or misaligned parts in torch head ?
Concave cut on one side and convex cut on other side
Slow cutting speed will produce ?
Fast cutting speed will produce?
Slow - vertical lag lines
Fast - slanted s shaped lag lines
Molten leftover from plasma cutting ?
Dross
Two main requirements for plasma machine?
Ac power and compressed air
What views are necessary for developing on center square to rounds?
Just a Plan view
When would you need more than twelve point spacing in round?
Fitting over 12” round
First step for groove seam?
Not hand groover
Dress the hook material down to 4 metal thickness using smooth hammer
When folding for groove seam you should always?
Fold slightly less than nominal size
What device controls the motorized zone damper ?
Central control panel
Drill bit angle for mild steel?
Stainless ?
118 Mild steel
130-140 SS
What method of power breaking should be used when bending SS?
Air bending
Can SS be soldered?
Yes
Silver brazing is a form of _____
Hard solder
What settings must be adjusted before spot welding SS
Increase pressure , decrease current
Finishing SS procedure?
Grind, sand, polish, buff
What is a turning machine used for?
Forms pocket for wired edge
Wiring machine is used for?
Turn the edge and close a wired edge pocket
What type of stake is E?
Beakhorn
The metric system is also known as what
System international (SI)
1 ton is equal to how many KG?
1000KG
Another name for hammer lock?
Clinch lock
Net vs gross pattern
Net is without allowance
Gross is with allowance
Which Seam would you use to attach around collar to a square to round body
Elbow seam
Centre line radius for HVAC elbows vs blow pipe elbow
1&1/2 for HVAC vs 2&1/2 w centreline blowpipe (width of duct)
Radial line PD can be described as
Start from a vertex
What fittings developed from radial line?
Cone flashing, tall cone, tapering cones, reducer, increaser
Radius on gooseneck ?
1/2 W
Gooseneck and roof ventilator height
18”
Rain cap diameter
2x pipe it’s attached too
Gap from rain cap to pipe
1/2 W of pipe
Angle of rain cap
30 degree
Spacing between fasteners on round vs straight objects
Straight will have one less - 8 fasteners 7 spaces
Round will have same number - 8 spaces 8 fastner
What must be in place for a brake to work at full capacity ?
Angle bar
-If angle bar is removed reduce 4 gauges
-If insert bar is removed reduce 7 gauges
What must you do if your metal thickness is within 4 gauges of break rating
Move nose back 2 metal thickness
What is a trammel point
Beam compass
Gauge for ferrous metal?
Non ferrous ?
Ferrous- Us standard
Non ferrous - Brown and sharp (american standard wire gauge)
Another name for duckbill snips?
Combination snips
Best tool to transfer pattern into sheet metal
Prick punch
Files are classified by
Length, shape, cut
Use a hand groover that is
1/16 bigger than your groove seam
Brittleness
Ability to withstand distortion
Ductility
Ability to withstand stretching, bending, twisting
Elasticity
Tendancy of metal to return to original form
Hardness
Ability to resist forces, resists penetration
Malleability
Ability to withstand mechanical processing such as rolling
Strength
Amount of high steady stress metal can handle, SS is strong
Toughness
Opposite of brittleness, ability to withstand impact
Least noble ?
Most noble?
Least - aluminum
Most - SS 300 series then bronze then copper
Brass is
Copper and zinc
Bronze
Copper and tin
Mig uses ____ on mild steel
DCEP reverse polarity
Orthographic projection
Taking an isometric drawing and having three sides drawn
When would you use spray transfer type welding?
Mig welding aluminum, 85% argon
What flux is used for galvanized
Muriatic acid
How do you seal a copper roof?
Solder
What type of stake is this?
Conductor
