1
Q
Classes of fit
A
Class 1 - loose (like ur mum)
Class 2 - free fit (most A/C screws)
Class 3 - medium fit (most A/C bolts)
Class 4 - close fit
Class 5 - tight
2
Q
Thread pitch gauge
A
Measures threads per inch (TPI)
3
Q
Crest
A
Top/ prominent point of the thread groove
4
Q
Root (fasteners)
A
Bottom part of thread groove
5
Q
Flank
A
Angle that runs from root to crest or crest to root
6
Q
Thread angle
A
Angle between two adjacent flanks
7
Q
Lead
A
Distance moved in one turn
8
Q
Major diameter + minor diameter
A
Male/external thread : crest to crest
Female/internal thread : root to root
Minor diameter is vice versa
9
Q
Pitch
A
Distance between two adjacent crests
10
Q
Single + multiple threads
A
A single thread should be used where good locking power is needed
