Steel pipe for flag pole

I have one of those cheap aluminum flag poles because I don't want to spend $1200 on a high dollar one. It uses 2" pipe sections and works pretty we
ll, but it will bend in high winds. I used black iron pipe inside of it fo r several years and it worked pretty well, but in our last storm with 70-80 mph winds, it did bend and the black pipe broke at the junction (2 10ft sti cks). I'm looking for a replacement for the internal pipe that would be st ronger. Local metal place recommended sch40 1-1/4" in a 20ft stick but I w as thinking maybe some sort of roll bar tubing or similar. I'm not that fa miliar with the terminology or naming convention of the different metals. I can do up to 1-3/4" inside the aluminum sections. What would be a good c hoice for this?
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On 07/15/2020 01:01 PM, snipped-for-privacy@gmail.com wrote:

Do any of the landowners in your community have water wells?
My flagpole is one 21' length of 1" galvanized steel well pipe. Seems to be the standard length, our well has always had 21 foot sections, replaced when they corrode and get pinholes with new 21 foot sections.
The well company we use will either haul the old pipe off, or leave it. I'd give you one of mine, but looks like you might be one time zone too far away.
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I appreciate that. I'll check around, that may work.
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On Wed, 15 Jul 2020 13:01:32 -0700 (PDT), snipped-for-privacy@gmail.com wrote:

1 1/2 inch sched 80 pipe or 1 1/4 inch square tube with 1/4 inch wall thickness might fit (with rounded corners it is 1 7/8" across the diaganal) and good luck bending it!!
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I like that idea, but that also sounds HEAVY! lol Hopefully I can lift it in place! ;-)
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On Wed, 15 Jul 2020 20:54:39 -0700 (PDT), snipped-for-privacy@gmail.com wrote:

You SAID you wanted something that would not bend in the wind - - - -
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wrote in message
I like that idea, but that also sounds HEAVY! lol Hopefully I can lift it in place! ;-) ========================================https://www.homedepot.com/p/0-91-in-x-2-in-x-20-ft-12-Gauge-Galvanized-Metal-Tubing-Fence-Post-20-007-190/202591987
Fence suppliers can get similar tubing in several diameters and wall thicknesses. My 50' TV antenna mast is made of 1-5/16" fence top rail at 1/4 the cost of Radio Shack mast.
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Great ideas. I'm going to do some checking around today and see what I can find. I like the option of the Chromolly tube.
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wrote in message
Great ideas. I'm going to do some checking around today and see what I can find. I like the option of the Chromolly tube.
===================Sold by the inch: https://secure.chassisshop.com/partlist/5408/
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On 7/15/2020 1:01 PM, snipped-for-privacy@gmail.com wrote:

4130 Chromolly tube. Pretty sure it comes in standard 20' sections.
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I found a local shop that has the 4130 tube. Kinda pricey stuff, but to ke ep costs reasonable what wall thickness do you think would do the job? 1.5 " with 3/8" wall is about $18/ft. I don't think I would need that much wal l thickness but I really have no idea?
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wrote in message
I found a local shop that has the 4130 tube. Kinda pricey stuff, but to keep costs reasonable what wall thickness do you think would do the job? 1.5" with 3/8" wall is about $18/ft. I don't think I would need that much wall thickness but I really have no idea?
=============================I'm not a professional engineer so I can't design for you, and if I was one I wouldn't work for free.
You can search for sites like these: https://www.flagandbanner.com/flag_banner_poles/wind_speed_chart_for_flagpoles.asp
https://www.engineeringexpress.com/calculators19/
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snipped-for-privacy@gmail.com wrote:

That is a lot thicker than needed. The 20' one I have is 3" with 1/8" thick aluminum.
--
Steve W.

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On Monday, July 20, 2020 at 3:04:56 PM UTC-5, Steve W. wrote:

Good to know. I priced 1-3/4" .120 wall 4130 and it came to about $325! I think i'm going to go back to 1-1/4" sch 40 inside the aluminum. I thin k I only had 1" previously after seeing how Sch40 is measured from ID, not OD. I would like 1-1/2", but it's just a tad too big to fit inside the 2" aluminum at the joint. So I think stepping up 1 size, and making it 1 full 20' piece instead of 2 with a joint,,,,,, hopefully it will be enough.
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On Monday, July 20, 2020 at 3:04:56 PM UTC-5, Steve W. wrote:

Good to know. I priced 1-3/4" .120 wall 4130 and it came to about $325! I think i'm going to go back to 1-1/4" sch 40 inside the aluminum. I think I only had 1" previously after seeing how Sch40 is measured from ID, not OD. I would like 1-1/2", but it's just a tad too big to fit inside the 2" aluminum at the joint. So I think stepping up 1 size, and making it 1 full 20' piece instead of 2 with a joint,,,,,, hopefully it will be enough.
============================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/hvac-machinery/pipes-pipe-fittings-and-piping-detailswrought-iron-pipe/
http://www.iceweb.com.au/Tubings/Glastpipethread_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.
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On Tuesday, July 21, 2020 at 4:54:29 AM UTC-5, Jim Wilkins wrote:

=====>

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as

d-piping-detailswrought-iron-pipe/

al

am,

I agree the newer steel with a thinner wall is likely stronger, but it's al so 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 previou s bend/break happened at the joint where the threads were cut. Going a siz e larger should increase strength, and 1 solid instead of 2 should also hel p 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.
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On Wednesday, July 15, 2020 at 4:01:35 PM UTC-4, snipped-for-privacy@gmail.com wrote:

nd $1200 on a high dollar one. It uses 2" pipe sections and works pretty well, but it will bend in high winds. I used black iron pipe inside of it for several years and it worked pretty well, but in our last storm with 70- 80mph winds, it did bend and the black pipe broke at the junction (2 10ft s ticks). I'm looking for a replacement for the internal pipe that would be stronger. Local metal place recommended sch40 1-1/4" in a 20ft stick but I was thinking maybe some sort of roll bar tubing or similar. I'm not that familiar with the terminology or naming convention of the different metals. I can do up to 1-3/4" inside the aluminum sections. What would be a good choice for this?
Not exactly what you asked, but the maximum bending force is at the base. So you could probably get by with a pipe inside the bottom 15 feet.
Dan
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On Thursday, July 30, 2020 at 1:16:35 PM UTC-5, snipped-for-privacy@krl.org wrote:

So you could probably get by with a pipe inside the bottom 15 feet.

I completely agree with this. The break was at the top of the first 10ft s ection, so since I can get sch40 in 10 or 20ft lengths, I just went with a 20ft section in the 1-1/4 size instead of 1" as well as eliminated any join ts. That should fare pretty well for the next several years. If it fails, I may at that point upgrade to a larger diameter pipe and re-do my concret e hole in the ground.
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