What is 3A thread?
What is 3A thread? 3A/3B is a tighter fit than 2A/2B. Thread fits are developed using allowances and tolerances. An allowance is an intentional clearance between mating threads. Allowances are applied to external threads. The major, pitch, and minor diameter maximums are less than the basic size by the amount of the allowance.
What does 2A and 2B mean for threads?
Classes 2A-2B Class 2A external threads have an allowance, Class 2B internal threads do not. Classes 2A and 2B, for most engineering applications, offer the optimum thread fit that balances fastener performance, manufacturing convenience and economy.
What is the difference between a 2B and a 3B thread gage?
?Class 2B is the typical fit for commercial products and is used for fasteners and threaded parts. Class 3B is the tightest tolerance and used for close fit and high strength fastening applications where a close and snug fit are required.