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Doozer
02-24-2010, 07:24 PM
Well this is for all ye sayers of nay who doubted my 2 ton gantry.
http://i72.photobucket.com/albums/i169/kooldoozer/Machines%20and%20Stuff/SDC10920.jpg


Sheldon shaper, 1000 lbs.
http://i72.photobucket.com/albums/i169/kooldoozer/Machines%20and%20Stuff/SDC10982.jpg


DoAll band saw, 1000 lbs.
http://i72.photobucket.com/albums/i169/kooldoozer/Machines%20and%20Stuff/SDC10987.jpg


Bridgeport, 1800 lbs.http://i72.photobucket.com/albums/i169/kooldoozer/Machines%20and%20Stuff/SDC10990.jpg

Doozer
02-24-2010, 07:24 PM
Acra-Turn 1340 lathe, 1600 lbs.
http://i72.photobucket.com/albums/i169/kooldoozer/Machines%20and%20Stuff/SDC10997.jpg


Hendey Tool and Gaugemaker's lathe, 2300 lbs.
http://i72.photobucket.com/albums/i169/kooldoozer/Machines%20and%20Stuff/SDC10996.jpg

Gorton 9-J Mill, 3400 lbs.

http://i72.photobucket.com/albums/i169/kooldoozer/Machines%20and%20Stuff/SDC10993.jpg


She was as solid and steady as a rock!
No worries at all.

--Doozer

tryfred
02-24-2010, 07:32 PM
With a gantry and a trailer like that you are going to need a bigger shop...way too easy to bring stuff home...almost impossible to pass on any good deals you come across....enjoy...

Joe

The Artful Bodger
02-24-2010, 07:34 PM
I think you are a very lucky young man!:)

bborr01
02-24-2010, 07:34 PM
Hi Doozer,

Nice job on the gantry crane.

I was trying to figure out the winches on the sides. In some pics it looks like they are way up at the top and other pics it looks like they are down low.

Nice load of machines. If they are all new to your shop, you have got to feel like a little kid at Christmas.

Thanks for sharing,
Brian

Doozer
02-24-2010, 07:37 PM
I moved the winches from the top to the bottom.
Way more convenient. To avoid dragging my welding
equipment outside, I used 4 1/2" muffler clamps to
mount the winches. Good eye spotting them;).

They are all coming out of my shop and going south.
My total load is 17,000. The trailer says GVWR of 18,000.
So if the trailer weighs 1000 lbs or less, I am good!
I think I am going to take half of the machines off of
the trailer and make two trips. The journey is 680 miles.
Two trips will be much safer, and more legal too.

--Doozer

Jim Shaper
02-24-2010, 07:57 PM
What diameter and wall thickness are the uprights, and how tall are they?

recoilless
02-24-2010, 08:07 PM
It's like watching a dozen clowns get out of a VW and all walk into a phone booth!

Where are you putting all that stuff ?

Doozer
02-24-2010, 08:18 PM
The long uprights are 4" OD (called 3 1/2" nominal pipe) and wall thickness is .226" (schedule 40). They are 14 feet tall. Pipes are galvanized, and they had straight pipe threads on the ends, so I believe they were rigid electrical conduit. There is a welded seam inside, but it is smooth.

--Doozer

Jim Shaper
02-24-2010, 09:21 PM
I hope you never bump them with a load up there like that.

Doozer
02-24-2010, 09:41 PM
Not that I care about convincing you, but would you like me to lift up the heavy mill again and hit the gantry with a hammer?

--Doozer

Jim Shaper
02-24-2010, 09:44 PM
Only if you'd like a dented driveway.

That EMT is undersized even if it was structural tubing. Stay safe.

Too_Many_Tools
02-24-2010, 09:47 PM
How did you rig that Sheldon shaper?

TMT

Doozer
02-24-2010, 09:49 PM
It is not EMT thin-wall conduit.
It is GRC Galvanized Rigid Conduit, which is basically schedule 40 pipe.

"How did you rig that Sheldon shaper?"
I used an endless sling under the front and the back of the ram.

--Doozer

doctor demo
02-24-2010, 10:07 PM
They are all coming out of my shop and going south.

--Doozer
Curious about the move south. Are You liquidating or moving?
Nice gantry, fairly level ground helps with stability too.

Steve

Doozer
02-24-2010, 10:18 PM
Moving. My toys stay with me.
It took a long time to find them.
I am not starting over. No sir.
When I take up residence in the
land of milk and honey, I will let
you all know. I will need some
new neighbors.

--Doozer

Jim Shaper
02-24-2010, 10:18 PM
Schedule 40 anything isn't an appropriate material for a crane IMO. It's ductile, and once it starts going, it keeps going.

I don't really care what the wall thickness is either, you're way outside a comfortable safety margin at that height. I'm pretty sure to be within anything resembling industry standard at that height you'd need to be over 10" diameter on your uprights. That's a really big effen lever you've got with a lot of weight on the end of it.

Guy lines would be a good idea.

I've got 4" square .187 wall structural tubing 9' tall for the corner uprights on my bridge crane. They literally wiggled 1/2" at the top when struck by hand (prior to bracing them to the building - which was always in the design). This was after being solidly anchored to the concrete. Industry standard for that much load (also 2T, but with the appropriate 5:1 safety factor) free standing is no less than 7" square tubing with .125 wall. The circumference of the support makes far more difference than the wall thickness.

I'm not a ME, so what I did was based on calculations for deflection and then compared with other commercially available designs. I went down in size due to the tie-in's to the walls. If it were free standing, my crane would be dangerous - even though it's anchored with (4) 1/2" anchors 6" deep into 12" of concrete at each of the four corners (the slab was poured with the knowledge that the crane's feet would be mounted in the locations it was).

Doozer
02-24-2010, 10:26 PM
More and more clowns emerge from the Volkswagen.

http://i72.photobucket.com/albums/i169/kooldoozer/Machines%20and%20Stuff/SDC10924.jpg

http://i72.photobucket.com/albums/i169/kooldoozer/Machines%20and%20Stuff/SDC10928.jpg

http://i72.photobucket.com/albums/i169/kooldoozer/Machines%20and%20Stuff/SDC10930.jpg

--Doozer

Willy
02-24-2010, 10:39 PM
It just hit me...you didn't have much furniture in the house did you?

Hopefully your new digs will have a large shop.
I'm sure the wife will enjoy the extra space in the living room.:D

Jim Shaper
02-24-2010, 10:42 PM
Doozer, please don't take me wrong - I want you to stay safe. That rig makes me nervous as hell. If a machine were to shift on you, it could bring the whole works down. Please be careful.

FatWheels
02-24-2010, 10:54 PM
Hey Doozer,

If you're headed 680 miles south of Buffalo you must be headed to somewhere in North Carolina I'd guess. Let us know where you land.

regards,

Jim

Doozer
02-24-2010, 10:55 PM
Jim, I do appreciate all of what you are saying. Your crane may have 5 to 1 safety factor. Mine may have less of a safety factor. I do not feel it is unsafe for what I am doing with it. I have a Dillon load cell and I have tested it a bit past 2 tons, and there is no spreading, perceivable deflection, or other alarming creaks and groans. I hear what you say about things being unconstrained and such. When lifting the big mill, I considered chaining the bases together with chain to prevent any spread. I got the load 1" off the ground and checked things over real good. There was no spreading of the legs, and things appeared quite stable. I said forget the chains. I am not going to spout out how many degrees I have, because that is not relevant. What is relevant is the question of how safe my gantry is. For me, I believe it is. As a commercial product, I agree that a 5 to 1 safety factor is needed to cover the odd things that people do. I am quite familiar with force vectors, bending moments, and column loading, and static vs dynamic. If used on level, hard ground, I see no problems using my gantry. If used on a hill or a rocky road, of course all bets are off. I plan on using it within it's limits. No worries mate!
--Doozer

Too_Many_Tools
02-24-2010, 11:52 PM
It is not EMT thin-wall conduit.
It is GRC Galvanized Rigid Conduit, which is basically schedule 40 pipe.

"How did you rig that Sheldon shaper?"
I used an endless sling under the front and the back of the ram.

--Doozer

Okay...for a large shaper is that the way to lift it?

I have done it with smaller shapers but with larger (HEAVIER) shapers is there a danger with the ram coming off?

NzOldun
02-25-2010, 02:31 AM
The long uprights are 4" OD (called 3 1/2" nominal pipe) and wall thickness is .226" (schedule 40). They are 14 feet tall. Pipes are galvanized, and they had straight pipe threads on the ends, so I believe they were rigid electrical conduit. There is a welded seam inside, but it is smooth.

--Doozer

A quick check with my trusty old HP 33s shows the columnar compressive stress to be about 1075 p.s.i, assuming all the load on one side. IMHO this is low and in normal use I don't think you've got a problem. Just don't EVER try to lift other then directly vertical. Your configuration makes this very unlikely (but not impossible!):)

R W
02-25-2010, 05:47 AM
- That rig makes me nervous as hell. If a machine were to shift on you, it could bring the whole works down. Please be careful.

I feel the same way.

Dawai
02-25-2010, 08:53 AM
As long as he is lifting vertical, the lift is on solid flooring and does not shift, the load is between the feet footprint, no problem. I agree it should not be trolleyed or moved loaded. I've seen engine cranes folded up by a crack in the floor.

I, have lifted things with a single post, anchored, guy wired off, as long as it stayed vertical it could lift enormous loads. A crane is the same way, the further you boom out at a angle from the base, the less load it can lift, swinging a load complicates things greatly.

Any lift, be afraid. A chain/clevis/bolt/hook as it breaks and separates can shoot through you. Straps or chains across unpadded edges are likely to be cut, if.. Take nothing for granted, because it did, does not mean it will again. Pulling cable with a winch tugger, I have saw about twenty people get broken bones with the snap of the rope. They were lucky.

Most the lifts I do, they are 500lbs these days, I used to just grab and move it, except I filled my pants with blood a few times recently.. I guess them days are gone.

I am not taking sides, just stating a engineering fact, staying over the load center greatly increases the strength of a boom, aframe, crane. When it bows and goes, it does so quite quickly thou.. not much time to run, or wipe your rear end, the mortician will do that for you, or me. Right after they pack it with cotton so you quit pooing as they move you.

Most scared I was in the past few years was when I was lifting a house-trailer frame with the wrecker, it shifted, swung around and knocked a dent in my truck, about ten feet behind where I was standing operating the handles.. I was gone, like a jack rabbit.. I was in front of the truck still backing up before it hit the truck. It took me days to calm down. That could have been my time to get cotton'ed.

I saved that piece of frame.. to make a covered tool trailer with.

tryfred
02-25-2010, 08:53 AM
And so it continues….the mass exodus from NY…not a problem… we’ll just raise taxes a lot more on the few remaining here…that will fix everything…
Joe

Doozer
02-25-2010, 09:00 AM
Willy-
"I'm sure the wife will enjoy the extra space in the living room.:D"

Do you think a woman would put up with having so many machines?
I am still single, if that was not obvious already.:p
I do have some nice furniture, mostly because my mom and my sister convinced me that my place should look nice when I do have women over. Wanna make a good impression.;) I might someday find one who at least knows how to weld.:D

--Doozer

hojpoj
02-25-2010, 09:39 AM
Willy-
"I'm sure the wife will enjoy the extra space in the living room.:D"

Do you think a woman would put up with having so many machines?
I am still single, if that was not obvious already.:p
I do have some nice furniture, mostly because my mom and my sister convinced me that my place should look nice when I do have women over. Wanna make a good impression.;) I might someday find one who at least knows how to weld.:D

--Doozer

Chances are she'll be an artist if she does know how to weld.

...Then you'll be competing for workshop space.

MichaelP
02-25-2010, 09:41 AM
I might someday find one who at least knows how to weld.

...to weld your shop entrance shut?

dezy
02-25-2010, 10:22 AM
Height has always been an issue with my gantry.
But it is plenty strong enough.
Notice the come-along to keep it from rolling down the hill.
http://www.jamesdensman.com/images/DSC02684a.jpg

bob_s
02-25-2010, 02:31 PM
Jim, I do appreciate all of what you are saying. Your crane may have 5 to 1 safety factor. Mine may have less of a safety factor. ....... No worries mate!
--Doozer

Safety factor ~3 if you put the Gorton directly on top of ONE of your columns!

Doozer
02-25-2010, 02:37 PM
"Safety factor ~3 if you put the Gorton directly on top of ONE of your columns!"

I feel comfortable with that.

--Doozer

Jim Shaper
02-25-2010, 04:04 PM
Which assumes a static load - you can't lift anything and have a static load.

The lack of bracing between the uprights and the beam concerns me, as does the lack of signs of pins to keep the legs from twisting. Both situations could allow either of the legs to twist and therefore buckle as even the 10' of unsupported mast is well outside it's limitations for such an event. That's a big effen lever for such a weak column.

The pictures lead me to believe the whole crane is moving to place these machines further down the trailer - so we're talking dynamic loading and it makes me nervous.

I certainly hope I'm wrong, but you wouldn't catch me using that rig or being anywhere near it.

Dezy's looks much more stable.

Doozer
02-25-2010, 04:17 PM
If I drop something, I will post pictures.
Will that make you happy??
Jesus Christ!

Go post in the Chuck Norris thread.

--Doozer

JCHannum
02-25-2010, 06:01 PM
The pictures lead me to believe the whole crane is moving to place these machines further down the trailer - so we're talking dynamic loading and it makes me nervous.

That would be my concern also. On a straight lift, it could be OK, but I would not be comfortable with it for my use. If it is being rolled into place just a small stone could result in it's collapse.

It is quite alright to take a chance with your own safety, but when posting on a website, you should be prepared for criticism particularly if the potential for injury is as high as it appears with this rig.

Willy
02-25-2010, 06:38 PM
Doozer, please don't take Jim Shaper's comments the wrong way, he is only looking out for your safety and the welfare of your valuable iron. Posting pics is always a gamble, one is proud to display all the hard work put into a project and hopefully receive some accolades, but you should also expect some constructive criticism, especially when it's warranted.

I realize you know the limits of your gantry and are very careful in it's use, but it scares me too. It reminds me of a spaghetti bridge, in that it will hold one hell of a lot of weight in one plane, but if anything upsets this precarious balance it will be disastrous. The last picture in post #18 is especially scary as it looks like if the gantry rolled into the drop off in the garage, that load would start swinging!

Doozer, I'm almost 60, and have been a trucker most of my life, have hauled and loaded an awful lot of big iron in my day, and unfortunately have seen too many misadventures go wrong. Fortunately I have learned from other's mistakes. This is why the concern and warnings, we don't want to see you loose a machine, or get hurt, most of us have all been there and don't wish it on anybody. I kind of look at all of us as family, and although we may disagree at times, we still take each others well being seriously above all else.

So call us a bunch of old hens if you will, but it's your welfare and those near you that we're concerned about, not our egos.

That's all for now,
Your Mom

PS: when you're moving that stuff down south make sure you put on clean underwear, just in case you get into an accident.:D

Doozer
02-25-2010, 06:55 PM
It was almost impossible for me and my helper to push the gantry when loaded with a 1000 lb machine. This is with a concrete driveway that is dead level. It would be impossible for 2 guys to roll this thing by ourselves with a 2000 lb machine or let alone a 3000 lb machine. If you actually had experience with this kind of stuff, you would pretty much know that rolling under load was not going to work.
The pictures did not lead you to believe.
You lead you to believe.

--Doozer

wierdscience
02-25-2010, 08:21 PM
Looks good to me,only thing I don't like is the Galv. part,that stuff sucks to weld.

Is that Hendey toolroom lathe?

Doozer
02-25-2010, 08:37 PM
Yes, That is a Hendey T&G. Here is the thread.
http://www.practicalmachinist.com/vb/antique-machinery-history/hendey-tool-gaugemakers-lathe-before-after-199119/

The galvanized pipe was not bad to weld as a whole. Of course I ground the galv away from the weld joint and that worked well. The pipe spent 20 years outside before I got it, so I suspect the galv may have lost some of its punch over that time. I TIG welded as much as I could. That galv sure goes like to jump to your tungsten and blob it up. The larger welds were TIG for roots when ever possible and MIG welded for final fill. I was running the MIG pretty hot, and it was on the upper edge of globular transfer mode, on the borderline of spray transfer. Of corse that meant I had to position my workpieces at a 45* angle to get decent corner joint beads. I was able to push the puddle up hill a bit, but I had an electric hoist which made positioning not too bad. When welding to the beam I pre-heared it with the torch to make sure I got good penatration. I really enjoyed building it. I can't wait to get my gas bill for heating my garage while doing it. :rolleyes:

--Doozer

hardtail
02-25-2010, 09:46 PM
I rolled mine with a 4800# lathe on the hook..........that turned out to be a mistake, but luckily the gods were smiling on me that day........

Just about to embark on draggin another mill home, have a deckover trailer but I think I'll put this one in the pickup box.........I have warned others against this very thing...........

I commented b4 on your other thread and must say I don't care for the looks/physics of it but after X # machines and how many K lbs it looks like your meeting with success.

snowman
02-25-2010, 11:12 PM
I imagine that you are unloading the machines by backing the trailer up under the gantry.

I've lifted things with more OSHA unsafe setups, I'm not proud of it, but I've done it. In your case, I might have lengthened the chain on the chain fall a bit so I could be well outside of the way if anything did let go, but I'd have done it.

Hell, ya shoulda seen my last move. Got all the machines off the trailer without lifting anything vertically. I just left the last two inches to "chance". Figured that if I had to hire a wrecker, I'd rather do it to place the machine back upright than to unload each machine.

There's a lot of common sense that comes in to play when moving heavy stuff. I'm not like Ibew, I can't move heavy stuff without mechanical advantage. But I am able to move heavy stuff without getting hurt. A lot of it just requires being aware of where that machine is going to go, if it goes. I take it into consideration on every move, be it a foot or 50 miles.

I had a full size conversion van come off a pair of jackstands on me (or at least too close to me). My mom was watching and dang near had a heart attack. I haven't been within reach of an unstable "insert heavy object here" since.

Too_Many_Tools
02-26-2010, 12:00 AM
Willy-
"I'm sure the wife will enjoy the extra space in the living room.:D"

Do you think a woman would put up with having so many machines?
I am still single, if that was not obvious already.:p
I do have some nice furniture, mostly because my mom and my sister convinced me that my place should look nice when I do have women over. Wanna make a good impression.;) I might someday find one who at least knows how to weld.:D

--Doozer

No..no..you got it wrong.

When you bring the little lady home you spend time in the shop.

Her reaction will quickly tell you whether she is a keeper or not.

TMT

J Tiers
02-26-2010, 12:08 AM
Lot's of things "work". Until they don't.....

The main issue I have is the side-loading issue. I do NOT want to rain on anyone.... BUT....

I said I had concerns in the prior thread, about side loading, and I still do. it would NOT take a lot to brace that very nicely against most side load issues..... just adding to the length of tubes that the columns go through, and bracing them against the beam.

We don't want you to find out the hard way.... And I HAVE seen that happen. I've also seen the oddest lashups work when they had to.

MickeyD
02-26-2010, 12:32 AM
Doozer - what size is the I-beam and how long is it? Any deflection that you get in the I-beam from load is going to be amplified by the legs splaying out. The more it deflects from a static load, the more deflection load is applied to it by the legs moving outwards, sort of a vicious cycle. If it was me I would put together a safety chain to run at ground level to connect the two upright assemblies. It does not have to be real heavy, but it would prevent a splaying failure on a heavy lift.

J Tiers
02-26-2010, 12:37 AM
That's a decent idea Mickey has.....

The other side-load issue is the whole thing folding up sideways..... as both verticals bend where they connect to the beam.

hardtail
02-26-2010, 01:15 AM
My fear here is the height and twist........his bases although not braced very high are substancial........I had the same idea of chaining the legs together..........guess where the load was placed for transporting on the tandem trailer, chaining wasn't an option due to the back axle.........I had even compensated for this by improving my gantry design by movable castors being mounted on channel, flip the wheels up to sit on the channel for heavy lifts and down and movable for lighter........until one day you have a heavy lift and need the extra height

Jim Shaper
02-26-2010, 02:25 AM
You tried to move it loaded (but failed) - I stand correct in my presumption.

Doozer
02-26-2010, 09:31 AM
The legs can not spread because of the wheels. There are inboard and outboard wheels on each base. If the legs would want to spread outward, the set of wheels being offset inward would cause a jacking effect, and try and lift the poles. The jacking would occur because the tangent distance from the top of the pole to the contact centerline of the wheel is longer than the straight down distance from the top of the pole to the ground. Because weight is on the poles, this is prevented from happening. For the poles to spread and fail, they would have to bend outward to the point where the contact patch of the wheel gets out from under the vertical load given to the column. If the columns were to begin to spread, the outboards wheels would begin to become unloaded, and you should be able to swivel them by hand. With 4000 lbs on the gantry, I could not spin the outboard wheels.

Jim- You assumed I was moving the gantry along the length of the trailer to load the machines. I was actually lifting a machine, and backing up the trailer under the machine, into the garage.
Trying to move the gantry with a 1000 lb machine 1" off the ground and finding that it was not going to work was an experiment. Yes the experiment failed to achieve ease of moment of the gantry. I thought that was good information obtained from the outcome. So I moved the trailer. You presumed the whole crane is moving to place these machines further down the trailer. In fact it did not move at all when any machine was at load height. Your presumption was incorrect.

--Doozer

Evan
02-26-2010, 01:45 PM
There are several likely failure modes with that gantry design. One is slender column buckling. You can get some idea how close it is to that by ringing a pipe unloaded and taking note of the resonant frequency. Then put a maximum load on it by trying to hoist the back of your truck. Then ring the pipe again and note if the tone is much lower. If it hasn't changed much or at all then it is likely ok on that score.

Another very possible failure mode is for one of the bases to move out of alignment with the other. This will cause the rig to twist as if you had turned the top with a giant invisible hand and one end or both will fold where they attach to the bases.

The most likely failure mode is for the rig to collapse by folding into a parallelogram to either end because of an unexpected side load. The gantry has virtually no strength in that direction because of the extreme lever between the base and the top at each end. If a load should shift in a manner that makes it swing from side to side or is pushed and the traveler hangs up the bending loads on the vertical columns will be extreme.

A golden rule to prevent slender column buckling is that the maximum unsupported length of a column should not exceed 10 to 20 times the diameter of the column. A simple and cheap way to brace those columns is to weld a disk twice the column diameter on each column at midpoint. Then run three or four 1" iron straps from the top to the bottom.

Here is an example on a set of steps I built. By adding the strap under the stringer it more than doubles the resistance to buckling because the strap is placed in tension and has a tensile strength of several tons. It also nearly totally eliminates bounce and deflection. The steps will take a 1500 lb load without problem.

http://ixian.ca/pics7/columnbuckle.jpg

Then add some triangulation at the top and bottom, either large gusset plates or some stringers a couple of feet long. It only takes a little extra steel in the right places to greatly improve the load capacity and safety margin.

You don't have enough safety margin at present.

garagemark
02-26-2010, 02:08 PM
I like it. I have used better rigs than that, and I have been forced to do some, at least by the sound of this crowd, unspeakable acts. I'm still here thank Goodness.

Anyway, by the pictures, it looks as if this argument is kind of moot. It worked, it is done. You might opt to take a pointer or two to shore up the thing a little bit before you next use it, but you have already survived this part of the move.

Oh, and the land of milk and honey is actually a reference to Israel (Biblical). Something tells me that isn't really where you are going. If it is, then I would hate to pay your shipping bill for all the iron to get over the pond. ;)

The Artful Bodger
02-26-2010, 02:39 PM
If it was me and that was my gantry I would have a cable or two attached near the top of each vertical which I would take out and tension to some fast point. It would be better than nothing as protection against the sideways collapse hazard.

Doozer
02-26-2010, 03:31 PM
Evan-

I love those step stringers.
Remember the booms on the old Holmes wreckers?
Too cool.

--Doozer

comdiver
02-26-2010, 10:34 PM
Have you moved yet? Let me know if you need a hand, I couldn't find your number. Chip

Greebe
02-27-2010, 12:01 AM
Dude, are you a collector or a machinist?:D Did you buy out a shop or something, or were you just moving shops?

Greebe

Doozer
02-27-2010, 12:35 AM
Greebe, Nope, its all my stuff. Gotta get another mill, a grinder, a welder, a drill press, and a parts washer out of the basement.

Chip, I sent you an email.

--Doozer

Evan
02-27-2010, 12:55 AM
Doozer,

I just ran a stress calculation of your gantry. If a side load of only 100 lbs is applied at the top, say from a swinging machine, it produces a torque moment of 1200 ft lbs at the bottom of each pole. Because there is no effective cantilever support at the bottom that in turn is reflected to the top where the poles support the bridge and produces a 6000 psi bending moment on the top of the pipes.

That isn't good.

Greebe
02-27-2010, 02:03 PM
Thats cool. How long did it take you to collect all that machinery? You will have to give us some pictures of the shop after you get everything moved in.

Greebe

The Artful Bodger
02-27-2010, 02:13 PM
Doozer,

I just ran a stress calculation of your gantry. If a side load of only 100 lbs is applied at the top, say from a swinging machine, it produces a torque moment of 1200 ft lbs at the bottom of each pole. Because there is no effective cantilever support at the bottom that in turn is reflected to the top where the poles support the bridge and produces a 6000 psi bending moment on the top of the pipes.

That isn't good.

I am suprised that it would take a side load of 100lbs to bend just one of those uprights.

Jim Shaper
02-27-2010, 02:33 PM
It's on the end of a very long lever.

I was surprised how 4x4x3/16 tubing wiggled so easily at the other end of 9'. I knew I was "light" based on the normal dimensions in mass production free standing cranes, but it was an eye opener no less. Without having planned for the support bracing, I would've been screwed (back to the drawing board with $300 in tubing down the drain).

The issue of someone else seeing it is the precise reason I will never post pics of my bridge crane online. It's built as fail-safe as I could think of (far heavier materials than necessary in all shear joints), but I still don't want anyone else copying it. My ME friend who was helping me run calculations liked the trucks, but he didn't like the tubing on the uprights. Once I showed him the brackets that attach the columns to at least 2 studs each (at 2 places on the column) he was a lot happier with it.

We just want you to stay safe Doozer, it's not about ego at all.

Doozer
02-27-2010, 03:23 PM
I appreciate you all thinking about this. The gantry ended up in it's present form with no angle bracing up top mainly because I wanted to be able to raise the beam with the hand winches and make it easy to erect. I could not think of an easy way to make angle braces up top and still keep with the original concept of;
setting up the bases,
putting the beam on top of the bases,
inserting the poles,
raise the beam to the top,
then insert the pins.
It is also useful to be able to run the trolley all the way over to one side, for lifting small machines next to the trailer.
If I could think of some angle brackets for the top that would allow the easy set up, and allows use of the full width of the beam, I would add them. Nothing has really jumped into my brain that will satisfy these constraints. I am open to ideas, drawings on napkins, etc. I don't think it is the absolute best gantry out there, but it kinda fills a specific need of being easy to erect and it gives me full use of the length of the beam. It does seem really stable with a 4000 pound load on it ( I have a Dillon gauge ). I am the only one using it. The heaviest machine is the Gorton, which is 3000 and change. It has been working for me so far, yes I still have to un-load the trailer. I do know that it is imperative to set it up on a hard surface, make sure the poles are plumb, and I don't roll it under load. Still, If I had a good idea for the top bracing, I would for sure do it.

--Doozer

j king
02-27-2010, 03:35 PM
Hi Doozer.
I would think a couple split collars that could clamp on the leg and another type clamp to clamp under the cross beam set at approx. 45 deg.. Set it up and fasten the braces.Would make a huge difference.

Just dont get hurt.I had my drill press laid on its side on carts to get it into the shop.This is a Big un. Guessing 2500 lbs.Top heavy as heck! Had to stand it up. It was the most scary thing I ever did and probably the stupidest! Heheee..Live and learn. Jim

The Artful Bodger
02-27-2010, 03:44 PM
It's on the end of a very long lever.



Jim, I was expressing suprise it would require as much as 100lbs.

Evan
02-27-2010, 03:45 PM
Fix the top like this at each end:

http://ixian.ca/pics7/gantry.jpg

j king
02-27-2010, 03:50 PM
I dont think thaat will add enough strength Evan. The legs arent long enough and too seepe of an angle. Dont mean to start a fight.LOL!! Take care.

I do like your pic. Wish I could do that fancy pants stuff..

Doozer
02-27-2010, 04:31 PM
Evan- You are a photoshop master!
So what you have there, doesn't that effectively just take 2 foot out of the column (load wise)? I mean it moves the bending moment 2 foot lower. If so I guess it helps some. As for running the beam up the poles, I guess I could replace the welded tab with a split collar. Hmm...

--Doozer

PS- The winch is attached at the bottom now, so that's not in the way.

Evan
02-27-2010, 06:00 PM
It isn't obvious what that brace does. First, it isn't connected to a point on the column but to a bracket that tapers in both directions from the point of connection. This distributes the load over a much greater length of the column than at the top socket. It goes further than that though. Because the down brace is bolted to the bracket at a single point the column can bend under load between the top socket and the bracket since the bracket can rotate on the end of the brace. That allow a side load to be distributed between the top socket and the corner brace instead of all the bending moment being concentrated at the socket at the top.

BTW, you cannot trust any photo of anything. Period. If you don't mind a little hijack I will show you something remarkable that I discovered some time ago. It is possible to create a non existent but very attractive person by combining the liknesses of two different people that are both reasonably good looking.

The image in the center is a composite of both women on either side. I didn't select any features, it is just a overall blend of the two faces at about 50/50.

http://ixian.ca/pics7/faces.jpg

j king
02-27-2010, 06:12 PM
But the brace isnt as stong under compression as it would on the opposite side.

The supports on the inside are way stronger.I am nowhere near as smart as you but do realize this fact. Built lots a stuff. He isnt moving the load from side to side and I would think 4 or 5 feet of open span would be plenty.

another thing he could do is run a chain from base Behind axle of vehicle if possible.That would keep the legs from separating apart. This would be only if the were room but you could make a short ramp to bridge over chain so it would work.Just a safety. Jim

Evan
02-27-2010, 06:37 PM
When the top moves toward either end it puts an outside brace in tension. A brace is much stronger in tension than compression since it will not buckle in tension. As for the bottom carriages a drop down locking out rigger like on a back hoe that extends in line with the bridge will keep the bottom from rotating and will distribute the bending load along the entire column.

J Tiers
02-27-2010, 07:09 PM
Evan's idea is good

I would go farther, considering how tall that thing is.


I understand your wish not to have stuff hanging down... it WOULD make it hard to assemble. So I have a suggestion.

Take Evan's basic idea.

Minimum idea:
Make the outrigger bar longer, minimum 2x what he shows. Extend the brace 2x longer to a substantial clamp on the column. You can PIN them together, you won't need to bolt, but the pins should be reasonably close-fitting.

maximum idea:
Make the brace about maybe 3x the one Evan shows, and deeper, better connected to the beam.
Put a substantial brace down to the pipe on teh side carriage. You can put a couple-three different pin spots for different heights.

That will tie the beam right into the carriage with a triangle. With pins it won't be a big problem to assemble. With a side load, one is in compression, but the other is in tension, so buckling isn't a huge problem...... but the braces ought to be big enough not to want to buckle.

The weak point will now be the tie-in to the beam. if well done, it should be good for any sensible side load.

Kibby
02-27-2010, 07:46 PM
Wish I had a gantry a few years ago. I had a deal on a Harig surface grinder. The seller had a skidsteer with forks on it, and we put it in the back of my then new Tacoma. That was the first mistake. I should have had a trailer, and the bed suffered dearly for my boldness.

When I got it home, it took me 5 hours to get it off the bed and onto a makeshift tiered arrangment of blocks and boards, and five seconds after I pulled the truck away from it, the whole thing toppled onto my tailgate. The dent was ghastly. :(

That was five years ago and I am still smacking myself around about it. Hell, I dont even have that truck anymore, and I still beat myself up about it. So stupid. You ever do something that is so insanely stupid that it embarrasses and shames you every time the mommory returns? Well this one is my crowning dis-achievement. :mad:

Rebuilding my shop will take time. This time, I will have a trailer and hire a forklift or a crane. Or just hire riggers.

Gawd, I can't believe I admitted this to you guys. :o

Dawai
02-27-2010, 08:34 PM
http://img.photobucket.com/albums/v85/ibewgypsie/Shopentrance.jpg

This one.. had a 24" heavy Ibeam on top, legs are 6x3hw rect tubing, about fifteen feet long, wheels were rollers with "edges" that ran on a fixed railroad track w.hydraulic motors. It was rated 3 tons with the large Ibeam.

It now has a 8" Ibeam on top, sitting unlevel, one end on a porch, other end on the driveway. It has picked up 6,000lbs recently. It has/had inboard angled braces to stop the side-shake and reduce bowing, It may collapse next time I pull a engine, it did set that century wrecker bed onto the 1941 truck.

Anyone that takes any lift without thinking everything over is asking for trouble. Some of the people here remind me of nascar thou, looking for a wreck.. wanna see a wreck, come around here. I break stuff weekly. I try not to be there when it hits.

Extra braces would not hurt a thing. I overbuild everything.. I got "ten" pounds of welding rod in the front suspension of my 48. Not counting the tig rod and the bench welding of aframe supports.