Help Needed: Engineers, Mathematicians...

[+joc]

I built a bird house for Purple Martins.    The house itself is about 5' tall x 3' wide.   I designed it to slide up and down on a 3.5" square x 24' pole via a crank and cable.  I have accomplished everything I set out to do...except for the final step.  Getting the pole in the ground.  It is very heavy...too heavy for me or anyone helping me to 'walk it up'.  Which was my first thought of how to get it in the ground.

I have a 4' deep hole.  After weeks and weeks of thinking and a few days of having the pole in place in the yard with the bird house on it...I have come up with a plan to get it in the hole.

So...This is a one trick pony.  If it falls...it will probably destroy the bird house and could seriously injure or kill anyone in it's quick path to the ground.

My plan:

1. Build an A frame.  The boards connected to a 'box' built around the pole ...just like the box at the top and bottom of the bird house.  One on either side to keep it from falling to either side and a third out front of the pole.

2.  Tie a pulley up into a cedar tree about 50' away the same height as the box for the A frame.

3.  Tie one end of the rope to the A frame box...run the rope through the pulley in the cedar tree and tie the other end to the hitch on my pickup truck.

4. Slowly pull the 1/2 nylon rope (max 625)  {pole and bird house maybe 300 lbs}

My thinking is that when I get the pole vertical, gravity will bring the pole down into the hole.  It shouldn't be able to fall backward due to the tension of the rope.  It shouldn't be able to fall to either side due to the A frame. If it doesn't go down in the hole as planned, it shouldn't fall forward due to the A frame leg in front of the pole.

One question is:  Should I did a trench so that the pole isn't flush with the ground but a little below grade.  I will if necessary, but I'd rather not.

I just have this feeling deep in my gut that I am missing something critical in this plan or that it is flawed in a way I am not seeing.

I Invite anyone interested with a mechanical mind to view the diagram ...more or less to scale....look at the pictures and advise me as to any flaws or concerns you may have.

Thank you very much!

You are looking at what I envision with the A frame.  the long steel pole is butted up against a wooden 3.5 square pole which will be cemented in the hole and strapped to the steel pole.  The crank will sit at the L end of the contraption.

 

 

Edited February 17, 2020 by joc

[+joc]

[Piney]

Your too far away for me to come with the 644 or 580. 

[+joc]

2 minutes ago, Piney said:

Your too far away for me to come with the 644 or 580. 

What is 644 or 580?

 

[Piney]

2 minutes ago, joc said:

What is 644 or 580?

 

Loaders. One has a extend-a-hoe which makes putting telephone poles in easy.

[zep73]

Dig a 3' deep 45 degree trench. 3' deep at the hole end. Then tie a rope to a car and pull/slide it in.

[+joc]

5 minutes ago, Piney said:

Loaders. One has a extend-a-hoe which makes putting telephone poles in easy.

That's what I thought!  We've had a lot of rain.  My truck is okay but anything like that will really muck up the whole yard...plus...they be a bit expensive 

[+joc]

2 minutes ago, sci-nerd said:

Dig a 3' deep 45 degree trench. 3' deep at the hole end. Then tie a rope to a car and pull/slide it in.

I had that thought myself...my other question is how long does the trench need to be?  Do  you think I'd still need the A frame?

[+joc]

Just now, joc said:

I had that thought myself...my other question is how long does the trench need to be?  Do  you think I'd still need the A frame?

oh wait...if it's 45 degrees that kind of defines the length

[zep73]

2 minutes ago, joc said:

oh wait...if it's 45 degrees that kind of defines the length

The trick is to make it stable once it slides in, so you'll need something in the bottom of the hole that can take the stress.

Edited February 17, 2020 by sci-nerd

[Wistman]

Isn't that a purple martin house on a high pole in the background of the first photo?  Smaller 'house' I see than your new one.  How was that one raised?

I've no knowhow to help you, but I had a purple martin house a while back.  Got rid of most of the mosquitos, which were overwhelming.  Good luck with yours.

[+joc]

2 minutes ago, The Wistman said:

Isn't that a purple martin house on a high pole in the background of the first photo?  Smaller 'house' I see than your new one.  How was that one raised?

I've no knowhow to help you, but I had a purple martin house a while back.  Got rid of most of the mosquitos, which were overwhelming.  Good luck with yours.

That is one of 3 I had.  I took down the other two but left that one because I don't want them to come...they should arrive any day now...and not have a house...they might leave and not come back.  That is really electrical conduit and I was able to telescope one pipe inside another so it was pretty easy.  But they are a pain in the butt to clean out ... and I'm not getting any  younger so I thought I'd put up one house that I could easily access without getting on a ladder.

[Wistman]

Yeah, cleaning the house is a huge problem.  Your solution seems excellent...if you can get it up in the air and stable.  I had a hard time attracting the martins to the house initially...other birds wanted it and I had to chase them away, which was a huge pain...and something I really don't much like doing.  But I did get purple martins to come after a little time, and they returned for a few years (till I moved away.)   Once the mosquito population was under control, I was able to install a big garden and enjoy being in it.  Wonderful, helpful birds.

[+joc]

31 minutes ago, sci-nerd said:

The trick is to make it stable once it slides in, so you'll need something in the bottom of the hole that can take the stress.

I plan to fill the hole with concrete.  I was about to go to Home Depot and get the rope and the boards ....but...I think you are correct...so I am going to go dig a deep trench first...

Thanks! 

Any other ideas are appreciated!

[zep73]

24 minutes ago, joc said:

I plan to fill the hole with concrete.  I was about to go to Home Depot and get the rope and the boards ....but...I think you are correct...so I am going to go dig a deep trench first...

Thanks! 

Any other ideas are appreciated!

At the side of the hole where the trench is, there will be only 1' to support the pole's weight. You can make it stronger by making the trench 2' instead of 3', or by digging the hole deeper. Alternatively you could put a rock or a brick at that place. Wet concrete is not gonna give any support while placing the pole.

Edited February 17, 2020 by sci-nerd

[L.A.T.1961]

Is it possible to remove the pole, place the bird house over the hole in the ground and then pass the pole through the house and into the post hole.?  

[+Desertrat56]

1 hour ago, sci-nerd said:

Dig a 3' deep 45 degree trench. 3' deep at the hole end. Then tie a rope to a car and pull/slide it in.

That is what I was thinking while reading the description.  You need a ramp type trench to guide the pole into the hole.

[+joc]

56 minutes ago, sci-nerd said:

At the side of the hole where the trench is, there will be only 1' to support the pole's weight. You can make it stronger by making the trench 2' instead of 3', or by digging the hole deeper. Alternatively you could put a rock or a brick at that place. Wet concrete is not gonna give any support while placing the pole.

Gotcha...I have the bottom of the pole now about 3' down in the hole.  I lengthened the ditch and slowly but surely I raised the pole by my own strength...supporting it at each juncture as shown in picture...

I still think I need an A frame...that will help support the pole until the concrete hardens a bit.   

I didn't really want to dig the ditch...but it was after all...the only way...so I really thank you for your input.  NOT wanting to dig anymore was clouding my judgement and not allowing me to see the reality.

Also...because I dug the ditch and now have the pole way towards the bottom...I believe I am at enough of an angle that, with A frame employed...I should be able to just pull it straight up with the truck without need of a pulley in yon cedar tree....what thinkest thou of that?

[+joc]

46 minutes ago, L.A.T.1961 said:

Is it possible to remove the pole, place the bird house over the hole in the ground and then pass the pole through the house and into the post hole.?  

No...that pole weighs over 200 lbs.  

[+joc]

oops forgot the pictures

[zep73]

38 minutes ago, joc said:

Gotcha...I have the bottom of the pole now about 3' down in the hole.  I lengthened the ditch and slowly but surely I raised the pole by my own strength...supporting it at each juncture as shown in picture...

I still think I need an A frame...that will help support the pole until the concrete hardens a bit.   

I didn't really want to dig the ditch...but it was after all...the only way...so I really thank you for your input.  NOT wanting to dig anymore was clouding my judgement and not allowing me to see the reality.

Also...because I dug the ditch and now have the pole way towards the bottom...I believe I am at enough of an angle that, with A frame employed...I should be able to just pull it straight up with the truck without need of a pulley in yon cedar tree....what thinkest thou of that?

The hole - on its own - is awfully wide. A frame will have to support the pole alone. Do you think it can? How about knocking a couple of spears in the hole, that you can tie the pole to?

Edit: A smaller hole - in the big hole - will also help.

Edited February 17, 2020 by sci-nerd

[+joc]

14 minutes ago, sci-nerd said:

The hole - on its own - is awfully wide. A frame will have to support the pole alone. Do you think it can? How about knocking a couple of spears in the hole, that you can tie the pole to?

I see your point. I have some 1 inch conduit out there. I will pound a couple of those deep in the ground and strap both poles to them and then pour the concrete... probably 3 or four of them. After the concrete set and everything is leveled I can always cut those off with my grinder. Good idea thanks!

[zep73]

2 hours ago, joc said:

I see your point. I have some 1 inch conduit out there. I will pound a couple of those deep in the ground and strap both poles to them and then pour the concrete... probably 3 or four of them. After the concrete set and everything is leveled I can always cut those off with my grinder. Good idea thanks!

Let us know how it turns out!

[+joc]

5 hours ago, sci-nerd said:

Let us know how it turns out!

I'll post a picture tomorrow of the pole IN THE HOLE!   

I really appreciate everyone's input!   Thank you so much!

That IS a wide hole....once I got it pulled so far the hole itself was holding the pole and I removed the A frame...worked real well though.  It was a very slow go.  In and out, in and out, in and out of the truck about a billion times...move a little...get out and look.  I finally got it where I wanted it and secure and dark was setting in.

I didn't even know until I cropped the pulley picture but it looks like the rope was about to snap!  Phew....thanks again!

[+joc]

Couldn't resist...