A thread on a drawing is labeled 1/2-20 UNF - 1B. The thread is
- bi-directional.
- external.
- internal.
Explanation
In a Unified thread callout the class suffix letter shows the type of thread: A denotes an external thread and B denotes an internal thread, so 1/2-20 UNF-1B is an internal thread of class 1 fit. The pitch and diameter give size, but it is the B that confirms it is internal rather than external.
MridulDev asking:
how come, please explain :)
Community Comments (2)
D
dimky Posts: 514 23.09.2013 / 20:52
Letter B is for internal thread, but letter A is for external thread.
Here is very good document: http://www.aviacionulm.com/archivospdf/Drafting.pdf
Here is very good document: http://www.aviacionulm.com/archivospdf/Drafting.pdf
M
MridulDev Posts: 48 24.09.2013 / 06:36
thank you :)
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