Tek-Tips is the largest IT community on the Internet today!
Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!
-
Congratulations cowski on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!
I need some info. or SPEC. on 1 1/4 - 32 UNF....
- Thread starter dinkylink
- Start date
UNF = Unified Fine
UNJF = Fine series with controlled root radius - the external threads of the UNJ family have a tightly controlled root radius, the size of which depends upon the pitch of the thread. They're widely used in aerospace components, as one example. The internal threads have an increased minor diameter but not a controlled root radius, so a standard tap can be used.
My data shows 1/4-32 UNEF (extra fine) and 1/4-32 UNJEF - but nothing for 1 1/4-32, which sounds like a special thread of some type.
UNJF = Fine series with controlled root radius - the external threads of the UNJ family have a tightly controlled root radius, the size of which depends upon the pitch of the thread. They're widely used in aerospace components, as one example. The internal threads have an increased minor diameter but not a controlled root radius, so a standard tap can be used.
My data shows 1/4-32 UNEF (extra fine) and 1/4-32 UNJEF - but nothing for 1 1/4-32, which sounds like a special thread of some type.
- Thread starter
- #3
I really don't have enough info about your project to help you. I've written a freeware program with lots of thread data. Maybe that and a good reference book will give you what you need.
In general though, a medium-fit unified internal thread would be class 2B - a close fit would be class 3B
As an example, a threaded hole that would accept a quarter inch bolt with twenty threads per inch would be defined on a blueprint as:
1/4-20UNC-2B or 1/4-20UNC-3B
you would also need to specify a thread depth
UNJ threads are normally class 3B
The program is at:
In general though, a medium-fit unified internal thread would be class 2B - a close fit would be class 3B
As an example, a threaded hole that would accept a quarter inch bolt with twenty threads per inch would be defined on a blueprint as:
1/4-20UNC-2B or 1/4-20UNC-3B
you would also need to specify a thread depth
UNJ threads are normally class 3B
The program is at:
dinkylink-
mrainer is right that the UNJ thread series is used in the aircraft industry. This series is better in vibration and shock than the UN series.
Look in Machinery's Handbook. It has all Unified Standard threads. A 1 1/4-32UNF sounds kinda weird. Are you sure that's what is needed: a 1.250-32UNF thread? Note that a UNJF-3A can fit in a UNJF-3B or UNF-3B but a UNF-3A can't fit in a UNJF-3B.
Lastly, note that drafting standards prefer the thread callout to be: .250-32UNF-2A rather than 1/4-20UNF-2A.
Tunalover
mrainer is right that the UNJ thread series is used in the aircraft industry. This series is better in vibration and shock than the UN series.
Look in Machinery's Handbook. It has all Unified Standard threads. A 1 1/4-32UNF sounds kinda weird. Are you sure that's what is needed: a 1.250-32UNF thread? Note that a UNJF-3A can fit in a UNJF-3B or UNF-3B but a UNF-3A can't fit in a UNJF-3B.
Lastly, note that drafting standards prefer the thread callout to be: .250-32UNF-2A rather than 1/4-20UNF-2A.
Tunalover
- Status
Similar threads
- Question
- Locked
- Question
- Question
