OT question (sort of) on hydraulics

[tmc_31]

Hi again guys,

One more sort of OT question. This question deals with hydraulics, specifically porto-powers.

What I want to do is separate two light pole sections. The light poles are galvanized steel approximately 70’ tall (in two sections) and about 20” in diameter at the joint. The poles are tapered and the joint between the two sections is a slip fit joint 1.5’-2.5’ long. Typically the poles are assembled by lubricating the pole sections with dishwashing liquid, then sliding the two sections together and pulling them together with two 3 ton cable hoists. The top section including the light fixtures, crossarms and top pole section can weigh up to 4 tons. This pole would have been sitting out in the weather for up to 10 years or so.

I want to separate the pole at the slip joint without damaging the top section of the pole. I am thinking of using two porta power rams with a single mule (hydraulic pump) to separate these sections.

My question is how large a porta power do I need (or how much pressure will it take to separate the sections)? Will a single mule power both rams to full capacity? Is there a better way to do this?


Tim

[Boucher]

Use at your own risk

Plug both ends. Adjust your cutting torch then snuff the flame and run the gas mixture into the cavity then ignite.

Then there is black powder or even a little calcium carbide and water.

Sometime I will tell you the story about putting some carbide in a hollow in an oak tree with a little water to get a squirrel out.

[Arcane]

If they are wedged together that tight, I think you might need a "shock load" to separate them. I would suggest applying a considerable bit of tension via large winches (or whatever is handy) to pull the ends in opposite directions then whale the tar out of the large flange at the bottom with a sledge hammer and see if that will break it apart. Once the "stiction" is broken they should come apart quite well.

This was the method we used to use to separate street light standards which have a straight section and a "gooseneck" section except they were just a fraction of the size of your standard and we didn't need to tug them apart, the sledge hammer was enough to do it all. Good luck!

[doctor demo]

I want to separate the pole at the slip joint without damaging the top section of the pole. I am thinking of using two porta power rams with a single mule (hydraulic pump) to separate these sections.
My question is how large a porta power do I need (or how much pressure will it take to separate the sections)? Will a single mule power both rams to full capacity? Is there a better way to do this?
Tim

Tim, You didn't say weather You needed to save the bottom section. If not just cut it off below the joint and slice it open with a torch or grinder with a cut off disc.
If You have to save both and can make them water tight lay the pole down and fill it with water and attach a pump that is used for expanding trench shoring and pump the two halves apart .

Steve

[tmc_31]

Boucher, you redneck!

That would get them apart alright. Don't know how the locals would like it. We used this method (fuel) in our tater guns until the schedule 80 pcv pipe started to blow apart (damn cheap a$$ Chinese glue).

Arcane,

Your point is well taken about applying a good whack when the pressure is on. I was trying to separate one of these poles with it standing in place a few years ago. The crane guy said had 5000lb on it and that was as far as he wanted to go. I told one of my guys to whack it with a 10lb sledge. When he did the pole jumped apart about 5' then settled back down on the stub. All I could see of my hand was a trail of dust!!

Did you work for an electric utility? I worked for West Texas Utilities for 26 years. Started out maintaining streetlights.

Tim

[Arcane]

Yes tmc_31, I worked for 35 years as a Journeyman Lineman for Sask Power, 16 years of them as a District Officer. Over that period of time, I managed to do just about everything related to power distribution. The four little words "and other related duties" in my job description made sure of that! It was an excellent occupation and one I am proud to have done.

[tmc_31]

Arcane,

I worked as a Line Serviceman for 10 years and then got into management. The last 11 years I was with them I was in Marketing & Technical Services as a Lighting specialist. I also found that working for WTU was some of the best I have ever done.

All,

I had another thought about how to get that base separated from the top pole section. Understand that we have taken the pole down and it is laying horizontal on saw horses. An associate suggested cutting the base section off about two inches below the joint, then slitting the left over piece inside the top section with a torch or plasma cutter. While I am sure this method would work, I am afraid of damaging the inside of the top section. It occurred to me the I might be able to build a "mill" that would attach to the inside piece and run a 3/8 carbide end mill down it to create the slot. DOC would be just the thickness of the pole section. I am not sure how best to attach the mill bed securely to the inside section. Does this idea have any merit?

Tim

[boslab]

Plug both ends. Adjust your cutting torch then snuff the flame and run the gas mixture into the cavity then ignite.

Then there is black powder or even a little calcium carbide and water.

Sometime I will tell you the story about putting some carbide in a hollow in an oak tree with a little water to get a squirrel out.

That was my first fishing pole, a scew top glass bottle, thicker the better [they were bloody thick, but not as thick as us] cup of carbide and a cup of gravel, gravel in the bottle, then carbide drop of water, screw the top on shake and throw the bottle in to the local Trout pond.
Wait till it blew then wade in and pick up the fish. The gamekeepers were not amused.
mark
BTW get 2 pipe vices and stick a ram between them to slide the poles apart, a little heat helps

[Arcane]

If you want to slit it, howzabout a skillsaw with a metal cutting blade? Easy to set to a predetermined depth and it won't wear down like a cutoff blade would. (get earplugs too! )

[tmc_31]

Boslab,

The two pipe vises with a ram is essentially what I had in mind. I plan to use 4 pipe vises (or something similar) with two rams, one on either side of the pole so as to exert equal force on either side of the pole. The question is how big do the hydraulic rams need to be to break this thing apart. The largest porto powers I've found are 20 tons. This would be 80,000 lb of force.

Tim

[tmc_31]

If you want to slit it, howzabout a skillsaw with a metal cutting blade? Easy to set to a predetermined depth and it won't wear down like a cutoff blade would. (get earplugs too! )

That is a thought Arcane,

I have successfully cut some sheet metal with a carbide tipped wood blade but this stuff can be up to .250 thick. Is there a metal cutting blade that will fit in a skilsaw that will cut this stuff? I have a 7-1/2" worm drive Skilsaw that I think will fit inside the pipe.

Tim

[wierdscience]

If you can get a tug on it and hit it with something like a demolition hammer while it's under tension that might do it.

[oldtiffie]

Pressure

20 tons maximum on a PortaPower is about right, but be aware of the pressures on the pump, ram and hoses - ~700 Bar or 10,000psi:

[Arcane]

A quick Google check brings up several hits for "metal cutting skill saw blade" including this one for Lenox brand blades. (I'm partial to Lenox brand for certain cutting tools). I noticed their website even has a Material Safety Data Sheet complete with an Emergency Telephone Number.

[tmc_31]

Arcane,

After reading your post I also searched on metal cutting blades. Search led me to the Evolution website. Just one of many but it shows real possibilities.

Tiffe,

Thanks, I became aware of the pressures involved after reading the specs on the Blackhawk Automotive Porto-Power website. Until I read that I had no idea that a hand pump would deliver that much pressure. Do you have any insight as to the results of trying to run two rams off of one mule? It seems to me that I should get the full 20 tons of force, just not full stroke as the mule will run out of fluid. Am I off base here?

WS,

The demo hammer may be a good idea. better than a single whack with a 10lb sledge.

Thanks for the advice guys,

Tim