Understanding gin pole rigging

[Jim_Rogers]

Recently we've begun reviewing gin poles and how to use them to lift timbers to erect frames.

I've had a friend and FF user email me directly about "understanding gin pole rigging."
And he has asked some very good questions and I feel that I should post these questions and try and show all of you the answers.

I'll do my best to show you what I have done and how it works.

First question: "What type of pulleys?"
and: First of all, we'll work on terms as I understand them. Hopefully I'll have them right but, I'm just a timber framer and I may not understand them all correctly myself. So if someone sees me using an incorrect term, then please educate me. Thanks.

In my setup there are three blocks, two are in the lifting rigging, as shown here:



The upper block is the stationary block, it stays at the top of the gin pole.
The lower block is the moving block, or lifting block, it moved up and down with the pulling of the line/rope.

The third block:



Is called the re-direction block. What his block does is it re-directs the pull line from vertical to horizontal, to make it easier for the crew to pull the line:



Now in each of the two lifting blocks are two pulleys. This means the line goes through the blocks four times before it is tied off to the upper stationary block.

What this means is the lifting ratio is 4 to 1:



More next post.

Jim Rogers

[Jim_Rogers]

Next question: "Where do I get them?"
and: Well, you'll have to do a search, probably an Internet search for a company that sells rigging. Or maybe a company that sells supplies for arborists.

Also: "What type of rope?"
and: The rope I'm using is 3/4" manila, I believe.

But before we talk about rope size, and type to buy, you need to do some research.

The first thing you need to do is figure out what is the heaviest load you'll be trying to lift?

This is what you'll need to plan on making your rigging strong enough to lift.

If you look closely at the label on my block:



You'll see a rating box and it say 2500 lbs. The label also say 3/4" rope.

This block is about 4 1/2" wide and the pulleys seem to be about 4" but I'm just guessing as it's very hard to measure them inside the block.



And he asked: "And especially the specifics of putting it all together, rope, pulleys, knots, etc."

Well, first of all you have to get the two lifting blocks and the line/rope. I was lucky and I borrowed mine from a friend who owns a crane company nearby me.

Once you have the two blocks you place them so that they are opposite each other and the hooks are on opposite ends. Next, one of the two blocks has to have a spot where you tie off the line with a special end:



These two blocks both had ends, I think they are called dead ends or deadmans, but I'm not totally sure.
The block on the left had the end of the line on it. It is protected with a metal lop especially made for these ends.
Then the rope is braided back into itself to make the end tight. But you can tie it off or get some other kind of fastener to hold the line together beyond the dead end.

Next you feed the line through the first pulley on one block and back to the first pulley on the second block. Be sure the lines are going in and out of the same side of the blocks, and the pulley is on the same side of the block.
Then the line goes through the second pulley on the first block and then through the second pulley on the second block.
Then to the dead end on the first block.
This is shown in the photo above where the ratio info is.

There is a special term used that means you're feeding the lines through the pulleys and setting up your block and tackle but I can't remember it right now.

Once you have your lines all in you're about ready.

The last thing you can do is place your other end of your line through your re-direction block and the rigging is all set, and ready to be attached to your gin pole.

More next post.

Jim Rogers

[Jim_Rogers]

You'll have to make a gin pole and what we did was we used a 6x6x16' piece of eastern white pine. We bored a hole through it and inserted a piece of treaded rod, and secured it with nuts and washers:



We added the base:



The base is another piece of eastern white pine, and so are the braces. And the base is 6x6 about 6' long and the braces are 3x5, I think.
The tenon layout is 1 1/2" off the layout face and 1 1/2" thick. And the spacing is 24".
And I have a pdf drawing of this gin pole I can email to anyone.

Next we added the chain to top:



And added the rigging to the chain:



When I borrowed this block and tackle, the blocks already had the line through them and the lines were duck taped together to keep them in place and this seemed like a good idea. So every time we used it; we'd cut off the tape and then afterwards replace the tape around the lines. This kept the lines from getting crossed up, and worked very well for us.

Before we raised the gin pole we'd secure the rigging to the pole so that when we moved it around the job site the rigging would travel with the pole.



This worked very well.

Before you raise your gin pole and after you have attached the chain, you need to attach your other lines.

The line that goes from the top of the pole backwards away from the lean is called is called the "back line". In my rigging this is also a manila line of equal size to my lift line. Then there are two lines going off to each side. In my rigging these are actually one long line with a loop tied in the middle.
But the setup looks like this:



And this:



And:



More next post.

Jim Rogers

[Jim_Rogers]

In Jack Sobon article written and published in Timber Framing the magazine put out by the Timber Framers Guild, Jack mentions that he added a fourth line to the top of his gin pole going in the opposite direction of the back line.
He called this line a "safety line." The purpose of this line is to prevent the gin pole, all it's rigging, and the timber being raised from falling over backwards. As you raise your timber up to place it in your frame you're raising the entire set-up's center of gravity. And when it's way up there it would be easy for it to fall over backwards right on top of you. So think safety first.

Also, I was told not to lean the gin pole over more than a 20° angle. So in my computer timber frame drawing program, I had drawn the frame, and added the gin pole and leaned it out 20°:

As shown here:


Now this made it easy for me to adjust the top pin's location to be directly over the post's top tenons and then measure the distance from the base of the post to the base of the gin pole. In the frames we used this was 5' 6".

So when we placed our gin pole, on the deck of the frame, and leaned it out, we placed the base 5' 6" from the outside of the post.

At one raising were we used the gin pole, the frame owner didn't like the looks of my old block we were using for a re-direction block and he replaced it with one of his own:



Last question for today:

"Can one man work with a gin pole, or are several people needed?"

We'll of course all raisings are easiest with more hands to help.
But, in Jack's article he said he raised his barn all by himself.

His rigging allowed him to lift very heavy timbers. I don't remember how many pulleys he had in his blocks or what his ratio was, but he didn't use a re-direction block, and just pulled his line straight down from the stationary block.

He attached a peg to his gin pole so that once he had raised his plate, he could tie off the line onto this peg and hold it up.
He had aligned his gin pole outside his building and directly over the plates position while it was on the ground, next to his barn.
Then once he had his plate up over his barn's posts top tenon height, he adjusted his back line to allow the pole to lean more and move over his post's top tenons.

He also had one end lower than the other, as I had mentioned before, and on this end he attached another piece of rope, known as a "tag line" to help adjust the plate to be directly over the top tenon. Once the plate was over the top tenon he lower the plate a little until the tenon just started to enter the mortise. Then he went up his ladder and aligned it. Came down and lowered it some more. Working the lifting line down he stitched the plate onto all the tenons of all the posts and braces from one end to the other.
Once all the shoulders were seated he pegged off the plate.

Figuring loads.

The eastern white pine plates we were going to raise were 8x8x16' and I looked on one of my charts of wood weights and saw that green pine was listed at 2.92 pounds per bdft.
An 8x8x16 is 85.33 bdft. Times 2.92 = 249 lbs.
Now with the ratio I have; which is 4 to 1. I divided 249 by 4, which equals 62.25 pounds. So that is the force I'm going to have to pull down the line in order to lift the plate.

I discussed this with a friend who had done many raisings with gin poles and he mentioned that I forgot to add the friction factor. He explained to me that there is a friction factor for all the lines turning all the pulleys in the blocks. And that this friction factor maybe as much as 40% of the load.

So, I re-figured my loads. Plate 249 x 40%= 99.6 lbs (rounded off 100). Now we have 349 divided by 4 =  87.25 lbs.

Jack Sobon figures that a man can pull down vertically his own weight, and for those of you who know me, I weigh a little more than 87.25 lbs. 

Can one person lift a plate weight 249 lbs, yes, but more would make it easy.

Here you see:



Five guys pulling the line. So 87.25 / 5 = 17.45 lbs each. Very easy to do.

That's it for today until I get some more questions.

Jim Rogers.

[TW]

Good teaching Jim!
You taught me the use of gin poles some years ago and now you explain it even better.

I want to mention that in the old days it was considered good practice among sailors to secure the hooks with a piece of twine or iron wire, when lifting loads with block and tackle.
I have done this way myself, and recommend it, just as a way to increase your own expected lifespan. I would prefer some self locking type of hooks if I had them.

[zopi]

Jim..Good Stuff! I highly recommend a copy of Ashley's book of knots for anyone interested in grassroots rigging efforts...lotta stuff in there from square rig sailors...

FYI..the main top yard on USS constitution weighs about a ton with the sail bent..takes about 20 motivated Chiefs to lift it...4 part tackle.

your, redirection block is called a fairlead..

setting up a tackle is called reeving...

and I agree whole heartedly with the use of a back tackle to keep the load from going over...don't ask me how I know this...lets just say it involves an oil derrick...

somewhere I have a diagram of a compound gin pole that can be used dynamically...like to lift a windmill
derrick off the ground and erect it...I'll see if I can figure out where it is..

[zopi]

I want to mention that in the old days it was considered good practise among sailors to sequre the hooks with a piece of twine or iron wire, when lifting loads with block and tackle.
I have done this way myself, and recommend it, just as a way to increase your own expected lifespan. I would prefere some self locking type of hooks if I had them.

It's called mousing the hook.

[Jim_Rogers]

zopi:

Thanks for the terms, I did find a few of them within the reading that DonP has posted.....
But I didn't want to go back and change anything.

Jim Rogers

[zopi]

De nada, just stuff I remember from my studies during bored hours on the ships...

The rig i was thinking of earlier was in the reader's digest book Back to Basics...

[Mad Professor]

Hi, can't figure out on the new forum how to post pics.  Help?

I've scans (with authors permission, THANK YOU RICHARD!!!) of huge bents being lifted by Mr. Babcock, his sons, Harry Sudan, and I think Jack Sobon in the reconstruction of the the upstate NY barns that were moved to Wolftrap performing arts.  This is a hand raising with only several men, of bents that have a 40 ' span (yes 40 FEET!).   Mr. Babcock did this yet again in raising another huge Dutch barn in conjunction with another device he called a "bull wheel" (e.g. a capstain) at Philips manor on Tarrytown.

The gin pole is a great device.  Many "old timers" used a raw hardwood tree that they would attach rigging to a "stout branch" at the end of the pole so no need for "modern devices" to attach your rigging.


Great post/thread Jim!!!

[thecfarm]

Mad Professor, click on to Help on the top of this page. Gives you all the information you need. We all seem to use xat to downsize the pictures. Reason for all this the pictures will always be here, thats why you need to put them in your gallery and to make it easier for the people, like me, with dial up. If you run into trouble, give a shout, someone will help out. Most time it's something very easy we miss.

[zopi]

If you go up to the top of the page and click image archive, you can load the images there, then link them to the post as you write the post.

[Mad Professor]

Mad Professor,click on to Help on the top of this page.Gives you all the infromation you need.We all seem to use xat to downsize the pictures.Reason for all this the pictures will always be here,thats why you need to put them in your gallery and to make it eaiser for the people,like me,with dail up.If you run into trouble,give a shout,someone will help out.Most time it's something very easy we miss.

I tried to every way I know, no go.

I was a member BEFORE the big crash,  sorry!!!!

 A member here was good about restoring things, ideas good, but it but did not work.


Anyway, moderator help, again?

[moonhill]

I have used black tape to tie off the hook.  Then I got tired of the tape, wire, twine.... and cut the hooks off and replaced them with shackles. 

Jim, how about the knot used in the guy lines for adjustment.  What knot do you/others use there?  I use a bowline on a bite. 

I use 4 guys/stays, always.  When turning the pole to face the other side of the building the guys get twisted, and I don't like that.  I have not made this up yet but will. It is a cap on the top of the pole which is held in place by a lag screw into the top of the pole.   It allows attchment of the guys and the freedom of rotating the pole but not the guys.  Pipe and some flat stock with a bit of weld and 4 holes.  This is only a few steps from a derrick with a boom.  Didn't I see a post with a fellow using something like that putting together a log building.  Anchor pionts for the guys?  I use an assortment of things  one involves a shackle, and running the guy through the shackle, as a word of caution, make sure the guy is not running on the bolt of the shackle it can unscrew while making adjustments and that is a bad thing, it should run on the horseshoe end of the shackle.   Tim B.

[Clovis]

Thanks for the post Jim. I never thought to use my sketch up program to figure out my gin pole placement. That will make things quicker and easier on raising day.

When I was a kid I found that same block and tackle setup laying on the side of the highway. There was construction going on at a near by hydro plant and it must have fell off of a truck. I sold the whole setup a year later for 5 bucks at a yard sale!

I Know "get over it"

[swampfox]

Much thanks Jim,  I don't know much of these systems and the way you laid it out was easy to understand.

[Jim_Rogers]

Mad:
If you can't post them, email them to me and I'll post them for you.
I have seen the picture of the bull wheel you mentioned and I have created my own. We have used it to lift plates only, not whole bents. But I know that it can do that as well.

Tim:
We don't get into fancy knots and things as yet. And we don't usually adjust our back line or side guide lines once we have them set.
Very time we used it, so far, we have set it on the deck and either used the frame's sills or posts to tie off to.

When we rotate the pole and lean it the other way, we undo the back line and two side lines and rotate them also. It's easy enough to do.

My hooks have keepers to hold them in place.

Thanks for all you comments.

Jim Rogers

[moonhill]

Jim, once that piece is in the air, I find it helpfull to move it a little to the left or right, forward a bit and to do this I/we use adjustable guys.  I only know 3 or 4 knots and they aren't too fancy, that is including my shoes.  There was a link on another post  on knot tying don't recall which post but I did bookmark it, but don't know how to attach it with the fancy blue high lite.  Tim B.

[Jim_Rogers]

Yesterday, a friend invited me over to watch/help him with his raising of a small garden screen house, he and his sons had prepared.

A while back he had attended one of my raising where we used a gin pole and he wanted to set himself up with some rigging for his own gin pole.

I pointed him to this thread so that he could understand the way I have done things.

I reviewed his blocks and he had a good set. I think each block had three pulley in each and each had a dead end for tying off the rope/line.

He didn't have another one for creating the redirection block, which this thread taught me is called the fairlead. So we had to just pull the lifting line down from the top block to raise his plates.

He constructed his own gin pole, 16' long, from a piece of  timber he had left over from one of his projects. And he got rained out on creating the proper "T" base piece or the side braces. So, I suggested that we could just nail a 2x6 some 4 to 6' long across the bottom of the gin pole to make a base. Which he did, although he didn't put the base on correctly, which is parallel to the through bolt going through the top of the gin pole. He had it perpendicular so we changed it.

After modifying the base and re-threading the line through the blocks to gain the most mechanical advantage we could, and that was three pulley on the top block and two pulley on the bottom block (5 to 1) we seemed to be all set to go.

We raised two end bents by hand with a few friends of his sons, and a neighbor who stopped by to help. And once up we braced them off. We then added some side posts and positioned the 18' long plate that we had estimated weight some 361 lbs near the side where we were going to lift it. And then began to raise the gin pole.

Well, he didn't have any decking down over his floor joist as yet, so we just put several pieces of plywood down where the base of the gin pole would stand to create a surface to support the base.
We then rigged the gin pole with the chain for the top block, and added the block and tackle line. We also only had one piece of line to use for the two guide lines so I created a loop in the middle of this 100' line for going over the top of the gin pole to be used as the side guide lines. Now, we needed a back line. And he didn't have any more rope or line to use.

The lifting line seemed long enough that we could use the excess for the back line. So, I created a loop and put that over the gin pole and secured all these lines down the pole so we could carry it onto his frame's temporary deck. We stood up the gin pole and secured it off with the side guide lines and then attached it to the lines around the plate to lift it up. Well, all these lines were all new and had never been used and it stretched quite a bit when put under a load. This leaned the gin pole out over the location it needed to be by several feet, not good.

We lowered the gin pole and re-rigged the back line and side guide lines, repositioned the base to the correct location and re-raised it. This time leaving it a little short until all lines were tied off. Then adding the load, and the lines stretching again a little bit the rig was in the correct spot. And we lifted the first plate up and set it onto it's posts top tenons. We started on one end post, then that post's brace top tenon was inserted into it's mortise and then we worked our way down the wall engaging each wall post's top tenon, until we got to the other end of the wall at the other end wall bent.

After the first plate was up and on, we stood the gin pole up plumb, and disconnected the two guide lines, and the back line and rotated it 180° to do the second plate. This gin pole was somewhat heavier at the top with all the rigging then at the bottom due to his temporary base arrangement, and we almost lost it when it started leaning over. I can really see why having a heavy base unit is important to keeping the center of gravity down.

After turning it around we secured the back line first and then the two guide lines and again we did this just a little short of the needed lean location so that the stretch effect would compensate the lines. And again this worked good.

We lifted the second plate with only one of his sons pulling the line, and he held the excess off as a safety anchor.
It was not very hard for his son to lift these plates by himself.

We set the second plate down onto the tops of the posts tenons in much the same way we did the first plate, and it went very well and even somewhat faster then the first time.

Shortly thereafter we stopped for a cook out and I had to leave before the frame was finished.... or the gin pole was taken down.

I learned some very good lessons at this raising, and so did all the others there.

One was having the right rigging for the job. We made it go with what we had, but I would have liked to have had at least two more lines on the gin pole. One for the proper back line and one as a safety line.
We also should have had a "tag" line on the plate to help guide it but with two helpers on step ladders on each end of the frame, in a safe area, we were ok in guiding it up the side of the frame.

The other good lesson was having a heavy base to the gin pole. With a short small 2x6 just nailed onto the bottom of the pole the base really wasn't heavy enough. And as mentioned the gin pole was top heavy with all the rigging up there.

I thought I'd pass this experience on to you so that you could see that it can be done by a new comer to timber framing, if you have the proper equipment and some guidance to setting it up....

Jim Rogers

[moonhill]

It didn't take, sorry.

Jim that's great.  I am fooling with a photo here and not sure if it will take, its a gin pole and on topic.  If this doesn't work I will try again some other day.  I just dragged it over from the desktop, I'm not very hopeful.

When moving the pole we just slacken the four lines and direct a bull(a big fella) to move the base while there is a man at each guy taking up or letting out line.  Than snug them up once more with the pole leaning just right and hook on the next piece.  Tim B.