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Special Threads - UNJC
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Posted by: Mick Waller

03/28/2003, 08:47:51

Edit
Does the J in UNJC only apply to the external thread?
Is the internal thread actually just UNC?











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Re: Special Threads - UNJC
Re: Special Threads - UNJC -- Mick Waller Post Reply Top of thread Forum
Posted by: RKimball

05/12/2003, 00:27:10

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Agreed, ... The idea is to machine the crest and valley of the thread and control the thread depth closely with the pitch and root. This method does away with the the peak and root tear that is normal in thread cutting. A smooth cut radius replaces this trouble area and prevents much of the reason a thread often hangs or snags by not having the fine slivers. It also plates more uniformly.
-randy-



** The worst suggestion of your lifetime may be the catalyst to the grandest idea of the century, don't fail to listen to suggestions. -randy-


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Re: Special Threads - UNJC
Re: Special Threads - UNJC -- Mick Waller Post Reply Top of thread Forum
Posted by: Jim Disharoon

04/22/2003, 16:50:32

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UNJC usually only applies to class 3 thread fits.
The 'J' requires a 'reduced root radius' that essentially provides a stronger thread profile, less like to break at the root radius.
Usually 'J' threads are only used in aircraft applications and in FINE thread configurations: eg. UNJF-3A

Coarse threads with the 'J' configuration are unusual: if an assembly requires a higher strength thread configuration, it would require a a fine thread with more thread engagement which would also provide greater 'strength'.

Yes, nuts are and can be produced with the 'J' thread configuration: eg. UNJF-3B
Typical standard items are 'MS'(military specification) higher tensile nuts, and lock nuts.

Jim Disharoon
TranSpec Fasteners













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Re: Special Threads - UNJC
Re: Special Threads - UNJC -- Mick Waller Post Reply Top of thread Forum
Posted by: abeykoon

04/01/2003, 01:06:25

Edit
: Does the J in UNJC only apply to the external thread?
: Is the internal thread actually just UNC?













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