Need help finding some chrome moly tubing.

[Strouty]

I am looking for some 2" OD with 1/2" wall, not even sure if it is made, but I was asked to find some. I need a 20' long piece. Anyone have any sources?


My supplier said that he found schedule 120, but could not find anything thicker. That was confusing, since apparently pipe is measured in schedules and tube is nominal.

 

[Muggzy]

I am looking for some 2" OD with 1/2" wall, not even sure if it is made, but I was asked to find some. I need a 20' long piece. Anyone have any sources? I can get schedule 120, but my supplier could not find anything thicker.

Not sure, but try onlinemetals.com

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[Strouty]

Been there, they only show 1/4" wall, I am pretty sure that is schedule 120.

 

[Muggzy]

Been there, they only show 1/4" wall, I am pretty sure that is schedule 120.

I've never heard of tubing with a wall thickness like you're describing. I'm far from an expert, but it sounds like something someone calculated and hopes that it exists.

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[Rookie2]

http://zanesville.craigslist.org/mad/5165041981.html

 

[theoldwizard1]

Looks like I am looking for Double Extra Heavy wall tube, it is just under 1/2" thick.

That is not "tube" it is "pipe". Pipe is measured on the ID, tube on the OD. 2" pipe has a an OD of 2.375".

Good luck finding that in chrome moly (4130)

 

[Strouty]

To make you happier, I need 1/2" wall or .500 wall not any schedule. My supplier said he found 4130 chrome moly tube in schedule 120, I guess that is what confused me.

 

[LXCam]

You need DOM tubing then.

Here's a start for ya.

http://www.onlinemetals.com/merchant.cfm?pid=9735&step=4&showunits=inches&id=283&top_cat=0

BTW why do you feel you need chrome moly with that wall thickness??

 

[Strouty]

No, it has to be chrome moly. DOM is not strong enough.

 

[LXCam]

You can special order DOM tubing in various materials. And what the tensile strength you're trying to achieve with a product that is not commercially offered??. I'd luv to see the engineering spec on this.

 

[tdkkart]

Are you sure solid bar wouldn't be easier to find??

 

[Strouty]

Are you sure solid bar wouldn't be easier to find??

Too heavy and because of the surface area, tube is stronger.

No engineers spec, but experience with pipe and DOM says it will bend under strain. Chrome Moly Tube has proven itself, just not sure how thick it needs to be, so we are shooting for 1/2".

 

[theoldwizard1]

Too heavy and because of the surface area, tube is stronger.

You are correct, but I think you are going to have to use a much larger (6-8" ?) mild steel tube/pipe.

 

[racingtadpole]

What is the application?

 

[stage20]

from what i know about tubing, you can go considerably thinner with chromemoly because it is stronger than mild steel. if spec calls for a certain thickness, you can always up your game in the thickness of mild steel, unless weight becomes a factor. usually around a 30% weight difference. if it bent before, the thickness was not speced correctly for the application.

 

[gte718p]

Too heavy and because of the surface area, tube is stronger.

No engineers spec, but experience with pipe and DOM says it will bend under strain. Chrome Moly Tube has proven itself, just not sure how thick it needs to be, so we are shooting for 1/2".

DOM is drawn over mandrel. your other option is hot rolled electric welded. You can get both tube and pipe in DOM and HREW. DOM is more expensive, slightly stronger, and easier to work with because it doesn't have the seam.

You can get tube and pipe in 4130 or 4140. Both are Chrome-molly. 4130 is good stuff, but expensive. I buy mine from Cherokee Steel, (local to me) or Air Craft Spruce. The second is expensive, but have an exhaustive collection of 4130. For 20 ft sticks, you either need to be local, buy enough to justify truck shipment, or have a serious budget.

 

[AndyCBR]

If no local supplier, Aircraft Spruce but you are going to pay a pretty penny for that 20' stick.

If you can stomach shorter lengths that add up to 20' that may make it UPS shippable.

 

[jimgood]

I'm betting it doesn't exist. No one lists any 4130 2" round tube with a wall thickness greater than 1/4".

Think about it...there would have to be significant demand for that size in order for anyone to manufacture it.

 

[jimgood]

These guys don't list a cross reference between OD and wall thickness but they do list wall thickness up to .625". They also list ODs up to 5", so...

http://www.twmetals.com/4130-tubing.html

 

[stage20]

one thing to note is most chrome moly sticks are randoms. they range from 17 to 24ft. i dont know any place that just stocks exactly 20ft pieces. not any place ive purchased from.

if you can use 8ft or less, any place that sells and ships tubing will cut it so it will ship UPS. i did this when i built the rollbar in my car.

 

[kf4zht]

Go to Ryerson's website, they have a stock list that is very complete. It will at least give you an idea if it's available.

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[Strouty]

This is for a ham radio mast that will be holding tow large antennas. It not only needs to be strong torsionally, but also be strong side to side. Has to be 20' so if I need to buy 24' and cut it I am fine with that. It also needs to be 2" OD to fit the standard hardware. If needed I may be able to make larger adapters, but I don't have the antennas yet and the drawings ****, so I don't trust them. I will need to talk to the owner as it will be extra if we need to modify things more than we all ready are.

I will also be galvanizing it so it won't rust and yes I have done this before, but the customer found the tube and that place is no longer in business.

 

[RustnGrease]

Just a thought Strouty, would it be possible to weld a smaller piece of tubing inside the 2" tubing to get your needed wall thickness?

Edit: I quickly looked at my local steel suppliers website and they sell this 2" O.D. X .240" WALL. It's listed as in 4' sections but maybe they buy it in sticks and cut it onsite. It's only listed as mechanical tube. Not sure if that's what you need.

 

[theoldwizard1]

This is for a ham radio mast that will be holding two large antennas. It not only needs to be strong torsionally, but also be strong side to side. Has to be 20' so if I need to buy 24' and cut it I am fine wedith that. It also needs to be 2" OD to fit the standard hardware.

With 0.500" wall thickness the weight of the pipe is actually working against you. As the pipe bends for wind load, it own weight is adding a lot of stress.

There are SO MANY WAYS to make an un-guyed tower SO MUCH CHEAPER ! If you are going to galvanize it anyway (and cold galvanizing is nowhere near as good as hot) I would start with a 10' section of 6" galvanized steel fence post, weld on a 10' section of 4" fence post, and then top it with 2".

Another possible solution is start with thinner wall tube/pipe, say 0.180-0.200". Weld on 4 sticks of 0.250x0.250, 90° apart, around the outside of the tube/pipe. These don't need to be continuous welds. Maybe 1-2" long ever 1-2'. If you are worried about torsional loads, make the welds continuous.

If you do use 4130, it has pretty good resistance to oxidation (rust) by itself.



Frankly, the best solution is guy wires, even it they are close in.

 

[theoldwizard1]

Another "seat of the pants" engineering approach.

Calculate the area of a slice of 2" X 1/2" wall tube (2.35 sq in). Now pick a largere OD tube (6" ?) and play with the wall thickness/ID until you have roughly the same square inches. The larger tube will be stronger in inline loads anyway. All metal is basically sold by weight (unless it is a very weird size/shape) so the cost will be about the same.

 

[Strouty]

The mast is on top of a tower, supporting a 45' by 30' antenna with another one that is about 20' by 12' above it. This is all mounted in a rotator so the customer can turn the antenna to the desired azimuth. The mast will be hot dip galvanized, cold is only for touch up or scratches, even then I use a mapp gas torch to heat the area first then apply the spray galvy, it lasts a lot longer that way.

The rotor is one of the main limiting factors, the mast must fit in it. Then the antenna brackets are designed for the same size pipe as the rotor, so it makes a mess of things if I go to larger diameter. You also add a lot more wind load with a larger pipe and the tower would need to be designed specifically for the new pipe.

 

[theoldwizard1]

The mast is on top of a tower, supporting a 45' by 30' antenna with another one that is about 20' by 12' above it. This is all mounted in a rotator so the customer can turn the antenna to the desired azimuth.

A much clearer picture now !

On towers I have seen like that the rotor is typically mount below the top plate and the top section (the pipe in question) mounts through that top plate. Is there a bearing of any kind there and is it also 2" ID ? Can you make it bigger, say 2.5-3.0" ?

If the rotor is the only limiting factor, I would go with welding 0.25 X 0.25 strips on 4 sides. The area that passes through the top bearing will have to be "filled" so that it has a continuous OD.


American Piping Products carries 4130 pipe/tube. Call them.

or Google 4130 pipe

 

[shawnspeed]

http://www.aedmotorsport.com/catalog/product/4130-round-tube
Could you take a length or 2" .250 wall, and sleeve it with 1.5", .250 wall and get there as well????These guys have good prices...Shawn

 

[zkling]

Too heavy and because of the surface area, tube is stronger.

No engineers spec, but experience with pipe and DOM says it will bend under strain. Chrome Moly Tube has proven itself, just not sure how thick it needs to be, so we are shooting for 1/2".

I'm betting this is your problem. In general it is better to increase diameter instead of wall thickness.

 

[Strouty]

I am not sure about the sleeving, so I can look into it. I am pretty sure what I am looking for exists, I wish I had a measurement on the existing one that I work with for another customer. I thought is was 1/2" wall.

The mast goes into the rotor about 10' from the top of the tower, so there are too bearing blocks that take all the side load. I can get the bearings in almost any size, but the rotor only really comes in one size, then you get into custom and that gets really expensive. The customer is all ready into about $75k so he is not worried about a couple of grand for a piece of tube, they want it to last "forever".

It is similar to this setup:

 

[Strouty]

I'm betting this is your problem. In general it is better to increase diameter instead of wall thickness.

I guess what I was saying was that we are going overkill because the tower is very close to the ocean on a good sized hill and we want to account for anything that mother nature can throw at it. The system was designed by an engineer to use 2" OD tube with 1/4" wall but we have seen it bend when an antenna is iced up and you get high winds. Those two things usually do not happen at the same time, so the engineers give a reduction based on some scale that engineers use and it says things are fine. Well the one time the wind and ice are there, the mast flexes too much and then you have a bent mast.

In order to use a larger diameter, and I agree it would be better, we would have major modifications, probably north of $10k just to get things to work together, and at that point I am not sure the tower would be strong enough to handle the larger diameter pipe, it would add a significant wind load as well as the weight of all the larger bearings, brackets, and anything else.

 

[theoldwizard1]

Could you take a length or 2" .250 wall, and sleeve it with 1.5", .250 wall and get there as well?

I am not sure about the sleeving, so I can look into it.

Sleeving is difficult on a long piece like that. OD and ID tolerance are such that the outer tube would have to be heated its entire length and the inner tube would have to chilled for the two to slide in. Even then, I would pin tehm together in multiple places.

 

[theoldwizard1]

In order to use a larger diameter, and I agree it would be better, we would have major modifications, probably north of $10k just to get things to work together, and at that point I am not sure the tower would be strong enough to handle the larger diameter pipe, it would add a significant wind load as well as the weight of all the larger bearings, brackets, and anything else.

You obviously know what you are doing, but I don't see that from the picture you have posted. The larger diameter pipe (4-6") would not weigh any more (because it has thinner walls). Yes, you would have to fab a custom "foot" to fasten the stick to the rotor top plate. You would also have to fab up new brackets for the for the antenna.




So how do you hot dip galvanize a 20' stick of steel ? Do places actually have vats that big ?

 

[latest project]

TW metals shows a 2x.375 4130 and Factory steel shows 2x.375, .500 and .625 4130

 

[zebrabeefj40]

Earle M Jorgenson list 2" OD by .500 wall 4130 as a stock item. http://www.emjmetals.com/pdf_indexer/pdfs/Tubing_and_Pipe.pdf
I've bought from them while working for other companies and they were great to deal with. Give them a call. http://www.emjmetals.com/

 

[pcmeiners]

Strouty did you forget Thomas's Registry..

http://www.thomasnet.com/search.htm...e&what=chrome+moly+tube&Submit.x=0&Submit.y=0

Boiler tube? .3 after a quick search, .5 is going to be hard
Sure one of the boiler tube makers could do .5 at a price. ; .22 is pretty damn heavy

 

[Strouty]

So how do you hot dip galvanize a 20' stick of steel ? Do places actually have vats that big ?

I can get longer than 20' dipped. I am actually going to dip one of my suburban frames at some point. My Dad did an F350 frame.

Thanks Zebrabeef, I will give them a call tomorrow.

 

[Strouty]

Zebrabeef, you did it. They are shipping it to Massachusetts and I will pick it up. Just under $500 for a 20' piece. The customer is happy as can be. Thanks to everyone that helped in the search.

 

[Thumper68]

Glad it worked out, this site is such a great resource!

 

[theoldwizard1]

Strouty, how about some follow up ?

Pics would be cool also !