I'm probably buying a used high tunnel or greenhouse this week...
The hoops are made of tubing and the ends have been drove in the ground. Pulling these out without crushing will be a trick. I've got to do it 50 times. Worth making some sort of contraption. I know the O.D. is nominally
1.6" but not sure of exact number.
I could drill the O.D. between two steel blocks and then use 1/4" bolts to clamp together. Then a loop of light chain to go around a long 2x4 for a pry bar. This would work but it would be slow.
If the bit in the ground can be seperated, make a fitting to allow water to be pumped down the pipe.
Otherwise, for your clamp idea, get some bicycle quick-release skewers. They make them for both wheels (about 5" long) and seatpins (about 1 1/2" long. the latter would work, drill & tap 5mm for the fixed side, or drill a pin (for each skewer) and set that crossways in the fixed side; lets you make slots in the free side so getting the clamp on & off is easier. Use as many skewers as you need to grab hold of the pipe.
The skewers with a steel internal cam are much better than those with an aluminium external one.
You are probably already working at pulling the tubing, but here would be my choice.
I would make the whole device out of 2X4 wood. Bolt two pieces together on the 4 inch sides, then drill a 2" hole centered where the sides meet. Then line the hole with layers of rubber inner tube material so it is well compressed when the blocks are clamped around the tube. Then use your lifter on the block.
My thought would be to use a shovel and pry up from the bottom if it is not too deep and the soil is not hard pan.
Another alternative would be to use a tubing cutter to lop off the tubes, and then make short sections to replace the ends. A circumstance that this might be your best bet is if the ends of the tubes are set into concrete below ground level.
Not sure if these ideas are any better so they are submitted for what there worth.
On Sun, 11 Oct 2009 08:50:18 -0500, the infamous "Karl Townsend" scrawled the following:
Is it cheaper and better to buy used and spend days removing, or to buy a new bender and poles, then do it yourself?
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20' bender
If it's chain link rail tubing, it's 1-5/8" (1.625)
Yours works, but I'd go beefier.
Drill a 1.625" hole in a block of purest BILLET aluminum by hand, and make is sloppy. Slit it, glue pieces of truck tube on the hole sides, or just drape it over. Use 3/8" bolts (each pointed opposite from the other to even out the tension when pulling) through the two pieces at
90 degrees to the first hole. Mount a pulling chain between these and tighten them to pull the posts.
Now use a farm jack on the new clamp-on unit. Well, unless you're really precise with a backhoe or loader bucket.
Alternatively, if they aren't in the ground all that stiffly, just wrap the pipe with truck tire tubing or sheet rubber, wrap chain around it several times, and pull up. That could save time.
On Mar. 4th, Winston described modifying a hydraulic lift table to do a similar job:
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There are some designs of =93fence post pullers=94 described on the web.
If the supports disassemble in sections, you might have access to the inside of the conduit to allow you to put a chain inside it with an expanding anchor (or plug) and be able to pull it out with a backhoe.
A ham friend [long dead] was friends with a rather famous ham, Sam Harris [W1FZJ] who went on to do multiple firsts. Sandy needed a tower pulled out; and Sam said he'd found the right tool in the weeds along the road.
It was a streetcar jack..... and the tower was no challenge.
I agree the blocks lined with tube approach. I'd glue the rubber in.
But I'd suggest you use bolts sized so you could use a air rachet or small impact wrench to install remove the bolts. If wood; weld the needed nut to a scrap so you can screw it to the wood. That way it's a 2 hand, not 3 hand, job.
My best idea, right now, is to waste an old vice grip welding clamp and replace the jaws with pipe clamp. Then I'll make this northern tool lever suggestion out of a couple scraps of tubing.
I won't build till Tuesday, so I got a couple days to sleep on it.
I came up with some ideas based on the clamps used on the tubing used in the oil fields. But way too complicated to build for pulling just
50 tubes.
So instead suggest you use something which has no metalworking content.
Consider making a loop of rope or webbing. Tie a prussic knot around the tubing. Pull with a Farm jack or a long ram hydraulic jack. Tying a Prussic knot will take less time than bolting some blocks together. I pulled about 4 feet of 1/2 inch rebar out of the ground using this method.
No ideas on a puller, but I've found that if you can spin the post while still in the ground with a pipe wrench first it will greatly reduce the force required to pull it out. The hoop houses I've seen use a separate ground post with a socket the hoop slips into so make a plug to insert to prevent collapsing while wrenching.
Consider making a loop of rope or webbing. Tie a prussic knot around the tubing. Pull with a Farm jack or a long ram hydraulic jack. Tying a Prussic knot will take less time than bolting some blocks together. I pulled about 4 feet of 1/2 inch rebar out of the ground using this method.
Use Google to see what a Prussic knot is.
Now, there's a GOOD idea. I didn't know of this knot. I'll try this first. I'll be bummed if it don't work, cause the unit is 40 miles away. Here's a u tube of it:
I am pretty sure it will work for you. With it forty miles away, you might want to drive some tubing into the ground and try it out before you go. I used a short piece of 2 by 4 under the jack to keep the jack from sinking into the ground. Would have worked better with two pieces of 2 by 4 so the jack could be more centered next to the rebar that I was pulling.
I used to go caving in Alabama, which is where I learned about Prussic knots.
illustrates the Prusik knot (correct spelling) but also mentions two others, Klemheist and Bachmann knots, which it says are better when loads are applied in only one direction. With a bit of practice, I imagine you could do a Klemheist a lot faster than a Prusik ... eg, maybe 15 seconds instead of 30. See
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1/3 down page for better Bachmann pictures.
By "try this first", do you mean at home, or at the worksite? If you have a few bits of pipe around your place like the stuff you'll be pulling, you could try it out in advance. Maybe take along a few square feet of 1/4" steel plate to lay on the ground under the base of the jack or pry-blocks, and a few odds and ends of wood blocking. If using a wooden prybar, I'd choose a 2x6 or
4x4 instead of a 2x4, but in preference to wood, would use a 5' prybar, possibly with a couple yards of cheater pipe as well.
Karl, if your pipe is unattached to the hoop, you can easily twist it out of the ground. Simply take a long pipe wrench, hook it on to the pipe, rotate the pipe in the ground while you are pulling up on the handle. If you pull upward on the very end of the pipe wrench, it will wedge and not pull off of the pipe. To save your back, install the pipe wrench about 3-4 inches below where your hands normally hang. This way your torso can be vertical (you're not bent over), your knees slightly bent and you can lift with your legs. I have pulled 12 feet of imbedded ground rod using this method. Pulled thousands of rebar (property corners) which are more difficult due to the deformations.
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