Fitting Fab Flashcards
Where are transitonal fittings needed?
Whenever a duct size changes
What happens when rectangular duct exceeds 4:1 ?
Experience airflow reductions
What is the raw edge connection and when is it used ?
Requires no allowances added and is used when the duct is being welded together
What is a standing drive connection?
Know as cp requires 2 allowances be added to raw edge of duct
What is hammerlock connection?
Known as tap in requires 3 allowances be added to raw pattern. Allowance is 3 times the width of the seam
When engineers draw prongs what are they drawn as ?
Drawn as net patterns
In what order should your brakes layout and seams go ?
Layout
Brakes
Seams
What machines do u use to form 3/16 male Pittsburgh ?
Easy edger or power flanger
What should u start with when developing the wrapper on a square 90 ?
Mark duct joint allowances
On the angled sides on Pittsburgh how much do I notvh ?
A transfer of angle notch
Do machines for heavier gauge have diffrent allowances ?
Yes
If a fitting has 3 flat sides what is it ?
A flat rectangular taper
If a fitting has two flat sides what is it ?
Offset or taper if the 2 sides are opposite
Of 2 flat sides are adjoining its a transition
What type of seams are flat sided transitions commonly used with besides Pitts ?
Button lock
If 2 sides are flat how can they be fabricated ?
As one peice
