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testraub

Structural Safety

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Okay, here goes, I plan on removing the coupling on my mega tree pipe (1" Black pipe)and putting another peice of black pipe inside (think it's 1/2" or 3/4") The fit is tight, but right now I have found a ridge inside the pipe (looks like just a line bead from end-to-end). For safety I was planning to install a 4' peice inside the 10' peice 2' and have it stick in 2' into a 5' peice. (hope I'm clear so far) In reality, how much of the inside pipe do I really need? And no offence Jimswinder, but your input will be ignored due to falling tree and snowman syndrome ;)

Tom Straub

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Guest Don Gillespie

testraub wrote:

Okay, here goes, I plan on removing the coupling on my mega tree pipe (1" Black pipe)and putting another peice of black pipe inside (think it's 1/2" or 3/4") The fit is tight, but right now I have found a ridge inside the pipe (looks like just a line bead from end-to-end). For safety I was planning to install a 4' peice inside the 10' peice 2' and have it stick in 2' into a 5' peice. (hope I'm clear so far) In reality, how much of the inside pipe do I really need? And no offence Jimswinder, but your input will be ignored due to falling tree and snowman syndrome ;)

Tom Straub

Tom if it were me I would go longer use a 6 foot piece and go 3 and 3 might be overkill but should make it a lot stronger.

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I realize we are talking about a lot of weight in those light strings. But the real problem is the lack of good tight guy wires. I suppose that in 2013 I will put my mega tree where my mouth is. Plan to put up my 15' mega tree and will be buying the kit of parts that you just add the black pipe and lights. One of the parts goes on the top of the pipe and has 4 arms that you add 4 guy wires and 4 anchors. A mast that is loose will bounce around and flex to the point of snapping.

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testraub wrote:

... right now I have found a ridge inside the pipe (looks like just a line bead from end-to-end).

No useful input on the question at hand, but that bead is because the pipe started as sheet, was rolled up, and welded. They do a better job of keeping the bead flush on the outside where visible, and may even grind it as part of the process. Water, gas, or whatever else you normally run through a pipe really doesn't care about the weld bead protruding.

Have you considered a larger size, instead of a smaller size, so that your coupling is the strongest section, instead of the weakest point? If you do stay with an inside section coupling like this, I would strongly consider making the joint an attachment location for mid span guy wires.

If you are looking to go closer to smooth on the outside, maybe step up for your pole sections, and use the current size for the inside dia coupling. Even then, realize that you now have two large cheater handles on it, that put more concentrated force on it than when you had the screw joint with couplings.

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Weather you go 3 feet or 4 foot of pipe on either side of the joint does not matter. The weakest point is the area where the two 1 inch pipe sections join with the sleeve inside. Your strength does not lie with how long your inner pipe is. You are reducing the support from 1 inch down to what ever size inner pipe you use and then you inside pipe becomes your weakest point.

Im assuming you want to reduce the diameter the coupling takes up for your hub to clear.

I have used 1 1/2 pipe 25 feet tall with three steel couplings and made the hub to clear the couplings. I tapered the entrance and exit of the hub and also slightly rounder the leading edges of the coupling and never had any issues with raising or lowering the hub.

Anthony

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Ok my mega tree fell this yeah while I was putting it up too many lights I suppose lol their are 200 strands from mits 100 ct m5 and the tree is almost 30' tall. To fix my problem of the pole from. Ending in Hal again I basically too three poles and attached them together making a mega pole if you look at the end of the pipe you see a triangle I attached them together using plumbers tape and bolts them used black gorilla tape around them so the light strands would it get snagged I'll take. Pic and post it in a min to show what I'm talkin about

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testraub wrote:

And no offence Jimswinder, but your input will be ignored due to falling tree and snowman syndrome :D

I agree with Max...put more effort into your guy wires...

1" Black pipe seems awful small for a 15' mega tree...

I used 2-1/2" aluminum, and look what happened...

but since you are just ignoring this, I would use 1/2" grey PVC :P

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jimswinder wrote:


but since you are just ignoring this, I would use 1/2" grey PVC  :P
LOL!!!

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Well since I know a thing or two about pipe I'll throw my 2 cents in. Anthony is correct, The weak spot will be the joint and it doesn't matter how long you make the inner pipe. At this small size you have no strength, even a threaded coupling on the outside is only slightly stronger. If you insist on using 1" pipe you must install guy lines at the top and at any joint between the ground and the top. I have used a internal sleeve before on larger pipe. The sleeve was only used to align the sections then I welded the joint. This still creates a weak spot but much less so. Last year during take down when my carriage got hung up and the lift line jumped the sheave AND the pull down line snapped, well then I snapped and cut one guy line and pulled the whole thing over with the opposite guy line. About the time the star got within reach the pipe tore apart at the weld. It was actually a little satisfying to watch it crash to the ground. That mega tree mast was 1 1/2" black steel pipe, 25' above ground with one welded joint 10' from the top and one unwelded joint 5' above the ground. The bottom section with the winch bracket welded to it bent to almost 80 degrees and the 20' top section stayed straight, breaking in the middle at the weld. I was able to reuse the two 10' pieces to make mini megas this year.

I don't think I've really helped any with your question. Your plan may work just fine. It depends on how much side ways force you put on the pipe. If you can manage to get all the stress to push straight down then you'll be fine. But if your mast is not perfectly straight and perpendicular to the earths gravitational pull, or the wind blows, or your light strings aren't space exactly equal then you could have problems.

If you want to try it, then 2' into each section should be enough. I would probably try it myself, even with what I just told you. If you haven't had a problem with the coupling you might be safe. If you could get someone to weld the joint for you even better.

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-klb- wrote:

jimswinder wrote:

but since you are just ignoring this, I would use 1/2" grey PVC  :P
LOL!!!


This Jim, is why I left you off the list of people I might listen to :D :D

The 1" Black pipe is fine for the tree. Been thru two seasons as a 12' Mega (1st Yr) and now as a hybrid tree (2nd Yr). Just trying to lose the cheap coupling between the 10' and 5' sections. Was thinking of welding the other pipe inside in hopes of makeing it a pulley type raise on the tree. ( If that makes any sense).

Tom Straub

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PipefitterDan wrote:

Well since I know a thing or two about pipe I'll throw my 2 cents in. Anthony is correct, The weak spot will be the joint and it doesn't matter how long you make the inner pipe. At this small size you have no strength, even a threaded coupling on the outside is only slightly stronger. If you insist on using 1" pipe you must install guy lines at the top and at any joint between the ground and the top. I have used a internal sleeve before on larger pipe. The sleeve was only used to align the sections then I welded the joint. This still creates a weak spot but much less so. Last year during take down when my carriage got hung up and the lift line jumped the sheave AND the pull down line snapped, well then I snapped and cut one guy line and pulled the whole thing over with the opposite guy line. About the time the star got within reach the pipe tore apart at the weld. It was actually a little satisfying to watch it crash to the ground. That mega tree mast was 1 1/2" black steel pipe, 25' above ground with one welded joint 10' from the top and one unwelded joint 5' above the ground. The bottom section with the winch bracket welded to it bent to almost 80 degrees and the 20' top section stayed straight, breaking in the middle at the weld. I was able to reuse the two 10' pieces to make mini megas this year.

I don't think I've really helped any with your question. Your plan may work just fine. It depends on how much side ways force you put on the pipe. If you can manage to get all the stress to push straight down then you'll be fine. But if your mast is not perfectly straight and perpendicular to the earths gravitational pull, or the wind blows, or your light strings aren't space exactly equal then you could have problems.

If you want to try it, then 2' into each section should be enough. I would probably try it myself, even with what I just told you. If you haven't had a problem with the coupling you might be safe. If you could get someone to weld the joint for you even better.


I have PLENTY of guy lines Had 3 at the 10' pipe, 3 at the 15' pipe and 16 more for the spiral tree.

Tom Straub

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Seeing your last two posts I think you have it well in hand. A couple of hints on welding the sections together. Drill fairly large holes trough the 1" pipe. Insert the sleeve, leaving a 1/8" gap between the 1" pipes. Weld the gap full then weld the inner pipe to the outer pipe trough the holes you previously drilled. This should provide the most strength.

I ran my lift lines up trough the center also so I too had to eliminate the couplings.

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Do as I did and go to the plumbing supply house and order a full 21' section of pipe. There will be no seams. Yes it is a pain to put in the sleeve in the ground, but no weak point. This works fine till you have the desire to go higher than than the pipe will reach. In my case I am using like 1.5" pipe and they were even able to deliver to my house.

Chuck

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Some reference material, if you ever wanted to know the weight or dimensions of pipe. Schedule 40 is standard size, so 99% of us will use Table 38.

Attached files Pipe specs.pdf

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jimswinder wrote:


but since you are just ignoring this, I would use 1/2" grey PVC :P

Touche Jim. :P:P:P:P:P

I'll give it 5 out of 5.

Pics look like a bit of bubble gum and bailing wire lash up to me...

As for the pipe having a welding ridge on the inside. And you want to put a piece of pipe inside to strengthen the coupling joint (which is a good idea). How about taking that smaller piece of pipe and grind a small divot so that it will slide inside of larger pipe. Only need to go about 1' above and below to do the job. Then drill a small hole and drive in a roll pin to hold it in place from one side. Do this just below the coupler.

But I still say guy wires are your best friend..

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I've seen it, but just trying my own thing :P Max, please read all the posts. I "think" I have enough guy wires :D And I did think of taking my grinder to the smaller pipe and putting a line down it to make it fit.

Tom Straub

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Sorry, not you Tom.
I was looking at that thing that Christopher built. But if it works Christopher, then what does it matter.

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Since this is a thread about Structural safety, If I wanted to build a free standing (no guy wires) pole with a 3' star on top 10' tall. What size black cast iron pipe would you guys recommend?

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