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[email protected] kleake1@gmail.com is offline
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Default Steel pipe for flag pole

On Tuesday, July 21, 2020 at 4:54:29 AM UTC-5, Jim Wilkins wrote:
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Pipe standards originated back when pipe was made from wrought iron which is
weaker than steel. The ID of modern steel pipe is approximately the same as
the old Extra-Strong standard.

http://machineryequipmentonline.com/...ght-iron-pipe/

http://www.iceweb.com.au/Tubings/Gla...ad_History.pdf

Chain link fence posts have the same OD as pipe, though thinner walls and
different size designations in fractions close to the actual OD. Electrical
conduit has the same ID as pipe and a smooth interior without the weld seam,
thus EMT and fence posts of the same nominal pipe size telescope in some
combinations.


I agree the newer steel with a thinner wall is likely stronger, but it's also way more expensive. I priced 1-3/4" 4130 with .120 wall in a 20' stick and it was $325. I priced 1-1/4" Sch 40, which is 1.68" OD and is $32 for the same 20' stick. I originally had 1" black pipe, so i'll be increasing by 1/4" OD and 1 solid piece instead of 2 jointed 10' pieces. The previous bend/break happened at the joint where the threads were cut. Going a size larger should increase strength, and 1 solid instead of 2 should also help a fair bit. If the 4130 was $100 instead of $300, I would go that route, but I just can't justify that much cost.