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UN thread designation

hhtw

Plastic
Joined
Mar 7, 2018
We rarely deal with Unified Threads and thus my knowledge is lacking big time. Which thread designation is proper, or is there really any difference?
17/8"-12 UN or
2 1/8"-12 UN

If they are the same, is there any reason to choose one over another? For example, with British pipe threads, which we manufacture a lot, I've never seen something like G 5/4" - it's always G1 1/4".
 

atex57

Hot Rolled
Joined
Sep 6, 2006
Location
SW Wisconsin
We rarely deal with Unified Threads and thus my knowledge is lacking big time. Which thread designation is proper, or is there really any difference?
17/8"-12 UN or
2 1/8"-12 UN

If they are the same, is there any reason to choose one over another? For example, with British pipe threads, which we manufacture a lot, I've never seen something like G 5/4" - it's always G1 1/4".
Please double check. They probably forgot the space between the 1 and the 7/8. Usually written as 1 7/8. Never seen 17/8 called out on any US prints.

Ed.
 

Larry Dickman

Titanium
Joined
Jan 30, 2014
Location
Temecula, Ca
i think he's referring to the 2-1/8 also being 17/8
I would say, if someone sends you a print with 17/8 on it, crumple it up and forget it. That will only be the beginning of your problems.

Or, send them a quote with the price called out in nineths of a dollar.
 

L Vanice

Diamond
Joined
Feb 8, 2006
Location
Fort Wayne, IN
If I was given a print that said, "17/8", I would first scale the print to see if it is a typo. Either way, I would suspect incompetence at the source of the print and exert caution in any business dealings.

Larry
 








 
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