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BigJohnT
10-16-2012, 08:36 AM
I built a small 6 ton shop gantry to help moving things around when needed and I was bored. The legs are adjustable on the beam. The beam was a drop from a construction job so it was free...

http://gnipsel.com/shop/gantry/images/gantry-14.jpg

Construction photos here (http://gnipsel.com/shop/gantry/gantry.xhtml)

John

bborr01
10-16-2012, 09:28 AM
Big John,

Nice job on the gantry crane. I am thinking about building one myself. I already have most of the steel, just need the time and energy.

Thanks for posting it.

Brian

Black Forest
10-16-2012, 10:22 AM
I built a small 6 ton shop gantry to help moving things around when needed and I was bored. The legs are adjustable on the beam. The beam was a drop from a construction job so it was free...

http://gnipsel.com/shop/gantry/images/gantry-14.jpg

Construction photos here (http://gnipsel.com/shop/gantry/gantry.xhtml)

John

Nice! Can I have it?

cegreen
10-16-2012, 11:41 AM
Very nice work! I'm planning to build a similar gantry, so your pictures are much-appreciated!

A few questions, if you don't mind:

1. Those are great looking casters what make and size are they, and where did you get them?

2. What size is your beam?

3. Any chance you could post a close-up pic or two of how the beam is clamped/bolted to the uprights?

Thanks for posting this!

-Chris

BigJohnT
10-16-2012, 12:49 PM
Nice! Can I have it?

You can borrow it any time you like...

John

BigJohnT
10-16-2012, 12:52 PM
Very nice work! I'm planning to build a similar gantry, so your pictures are much-appreciated!

A few questions, if you don't mind:

1. Those are great looking casters — what make and size are they, and where did you get them?

2. What size is your beam?

3. Any chance you could post a close-up pic or two of how the beam is clamped/bolted to the uprights?

Thanks for posting this!

-Chris

I got them from McMaster Carr. They are cast iron wheels designed for concrete and roll very easy even with a heavy load like the lathe hanging on it. Part number 2293T31, Desc Brute Caster With 5-1/4" X 7-1/4" Plate, Swivel, 6" X 3" Cast Iron Wheel, 3000# Capacity

I can take care of 2 and 3 this afternoon.

John

Black Forest
10-16-2012, 02:01 PM
BigJohn, can you swing by with it in the morning?

CCWKen
10-16-2012, 03:22 PM
Nice looking gantry but a little short on stability. Best not to move a gantry crane while it's loaded. That's not a wise maneuver and certainly not the intended purpose. A small screw left on the floor could ruin your day. Lift the load with the gantry then put dollies under the load to move. Of course, you can drive without seat belts, grind without safety glasses, paint without a mask or whatever else you want. I'm just sayin'...

Jaakko Fagerlund
10-16-2012, 03:59 PM
For some reason I would be a little afraid of that thing bending under a good load so that the ends bend away from the center outwards, as they are standing alone without horisontal support other than the small 45 degree piece at the top.

wierdscience
10-16-2012, 08:14 PM
Looks good,should work fine up to the rated capacity.Moving stuff with a gantry is much safer if the load is secured to the gantry at the base to eliminate the pendulum effect.

BigJohnT
10-16-2012, 08:17 PM
BigJohn, can you swing by with it in the morning?

Might be a bit of a stretch to make it to Germany in the AM...

BigJohnT
10-16-2012, 08:18 PM
Nice looking gantry but a little short on stability. Best not to move a gantry crane while it's loaded. That's not a wise maneuver and certainly not the intended purpose. A small screw left on the floor could ruin your day. Lift the load with the gantry then put dollies under the load to move. Of course, you can drive without seat belts, grind without safety glasses, paint without a mask or whatever else you want. I'm just sayin'...

It is extremely stable and safe, put your doubting Thomas away.

John

BigJohnT
10-16-2012, 08:19 PM
Looks good,should work fine up to the rated capacity.Moving stuff with a gantry is much safer if the load is secured to the gantry at the base to eliminate the pendulum effect.

If I was pulling it with a forklift I might be worried but pushing it by hand... no worries it is very stable and no swinging at all.

John

BigJohnT
10-16-2012, 08:21 PM
For some reason I would be a little afraid of that thing bending under a good load so that the ends bend away from the center outwards, as they are standing alone without horisontal support other than the small 45 degree piece at the top.

Don't be afraid it is really very strong and rigid.

John

BigJohnT
10-16-2012, 08:24 PM
2. What size is your beam?
-Chris

8 x 6 1/2 28lbs/ft beam.

ran out of time for a photo today...

John

sasquatch
10-16-2012, 08:51 PM
Who was "Doubting Thomas " anyway?

(The procrastinator?) lol

dfw5914
10-16-2012, 10:06 PM
Looks great to me. If anything, it's over-built.

BigJohnT
10-17-2012, 06:21 AM
Looks great to me. If anything, it's over-built.

Aye, that is a habit of mine to over build. Someone once said to me "if it looks good it will work, if it looks flimsy don't walk under it." or something to that effect.

John

Jaakko Fagerlund
10-17-2012, 07:49 AM
Don't be afraid it is really very strong and rigid.

John
So you have made calculations on how much load the overhead bolts take before stripping their threads (as the uprights make a nice big lever to pry them out of the large beam) and also how much load it takes to buckle the side posts?

If it has not been designed for something walking under, don't walk under.

BigJohnT
10-17-2012, 07:55 AM
So you have made calculations on how much load the overhead bolts take before stripping their threads (as the uprights make a nice big lever to pry them out of the large beam) and also how much load it takes to buckle the side posts?

If it has not been designed for something walking under, don't walk under.

Yes I did and the bolts are 1,265 times stronger than my ability to pull on the long levers. I used Grade 8 bolts with 120,000 psi tensile strength which is the same as your 10.9 bolts. So one of the 6 bolts has 17,000 psi proof load tensile strength the 6 total on each upright have 102,000 psi proof load.

John

toyjeep73
10-17-2012, 09:30 AM
Looks good.

I need to build something similar that is adjustable. Needs to be less than 8' tall to work in the garage, but around 11' tall for outside the garage. And light enough to take apart and assemble without a shop crane.

Any ideas?

BigJohnT
10-17-2012, 10:29 AM
3. Any chance you could post a close-up pic or two of how the beam is clamped/bolted to the uprights?


Chris,

Here you go... dang I need to paint the clamp tops and sides.

http://www.gnipsel.com/shop/gantry/images/gantry-15.jpg

John

BigJohnT
10-17-2012, 10:32 AM
Looks good.

I need to build something similar that is adjustable. Needs to be less than 8' tall to work in the garage, but around 11' tall for outside the garage. And light enough to take apart and assemble without a shop crane.

Any ideas?

I've seen some telescoping ones online, you might get some inspiration from them.

"Light Enough" is tough one to comment on... might think about some method to raise and lower the beam built into design... that could get complicated in a hurry.

John

Doozer
10-17-2012, 10:42 AM
Don't worry John. Half the people here didn't like my gantry
either when I posted it here. I like your beam clamps.

--Doozer

Bill736
10-17-2012, 11:07 AM
A very nice and sturdy looking job ! The design instills confidence , which is not always true with some other cranes I've seen online. Your attention to those details also tells us that you know to use care and planning when moving any heavy object . Again, very good work !

cegreen
10-17-2012, 11:14 AM
Thanks, John - much appreciated, and again it looks great!

-Chris

BigJohnT
10-17-2012, 11:23 AM
Thanks for the positive comments guys, you might also know that you can move the legs while the gantry is assembled just by loosening up the crab clamps and pushing the leg... all very safely done.

John

Rosco-P
10-17-2012, 12:25 PM
Enough information on the web from crane manufacturers that you don't have to "re-invent the wheel". Here's one which includes the major dimensions and sizes of the gantry members: http://www.wallacecranes.com/

BigMike782
10-17-2012, 07:07 PM
John,I like it...very nice.

If you have your asbestos undies on post it on one of the welding forums and watch them come out of the wood work.

BigJohnT
10-18-2012, 06:47 AM
BigMike,

That sounds like fun actually...

John

oldtiffie
10-21-2012, 02:02 AM
The only one who could/should design, certify and rate any significant lifting device is an experienced qualified structural/civil engineer.

It must be certified as being "designed to Code" with a certified copy of the Engineer's computations and certification - including his registration details.

"Eye-balling" such things in not "designing" or "rating" them.

BigJohnT
10-21-2012, 10:52 AM
I ain't selling them so take a chill pill...

John

CCWKen
10-21-2012, 12:52 PM
We just don't want your wife coming on here and selling your shop tools to settle your estate. Well, we might want the tools but not that way. :)

Be smart and use caution. If you're going to move loads, set the load on cross-bars on the lower caster supports as Wierdscience mentions. Then... Getter done!

BigJohnT
10-21-2012, 02:22 PM
I don't lift the loads that high to get them on cross bars :)

I always use hillbilly smarts and over caution when moving anything. There are no rules where I live so only the smart survive...

You would have to come to the auction to get my tools when I die... My daughters would not have a clue what to do with them nor would my son in law... I think he has a screwdriver a hammer and a small plastic tool box. On that note I don't think the auctioneer would even know what he is looking at so some of you must come to the auction if your still alive.

John

uncle pete
10-21-2012, 04:17 PM
Well to be honest, I've done literally thousands of lifts over the years, and I'm not a even a designated or licenced crane operator, nor have I ever run a proper "crane" of any kind. I've done everything with tracked excavators, etc. I am fully certified on those. I know lots of, and have worked alongside many licenced crane operators though. Most of what I know about proper rigging and lifting came from those people, and almost everything in that job is done from past experience, eyeball methods and good common sense mixed in with with the proper knowledge the courses teach you to obtain those certifications and some decent judgement of what is and isn't physically possible. But I can say that past experience and good common sense is the usual methods in that job. We just don't have engineers on call to redesign and calculate every single step on any job. Experience counts and B.S. walks. Eyeball methods can and are used every single day on any job site you'd care to name. And if you can't eyeball the job, you won't be employed after the first coffee break. Very highly specialized lifts usually are and do get calculated and engineered to the last detail when the weights start approaching very close to the equipments maximum capabilities. On very critical lifts, survey transits and even GPS can be used for very precise equipment placement. But hillbilly methods haven't failed me yet either, and I've been judged as competent to lift some VERY expensive and in HSM terms, very heavy equipment.

AFAIC? That gantry shows a well thought out design. Enough so it tells me the builder understands a lot about what's actually involved and it's limitations. My own eyeball estimates and judgement going by the pictures sure doesn't tell me any logical reasons why I wouldn't use it. I've seen and used far cruder built to do emergency jobs a long ways out in the bush.

Pete

darryl
10-21-2012, 05:04 PM
As uncle pete has alluded to, there are those who can apply an 'experienced eyeball' to a problem and 'get the job done', while there are countless others who may feel similarly qualified but simply aren't. My first thoughts when looking at that gantry were that hey- this looks like it's properly engineered. I've seen a lot of stuff that people here have made and posted about that I wouldn't trust, or would have done differently for various reasons (rigidity, strength, elimination of concentrated stress areas) and this gantry isn't one of those. I'm not easy to satisfy in regards to how things are made, but this one gets my ok.

BigJohnT
10-21-2012, 05:05 PM
I'm with you Uncle Pete, when I was in the oil patch I ran everything from a stiff leg crane that used a truck rear end with an electric motor and a couple of band brakes to lift and swing all the way up to 100' stick real crane. Oh the biggest lift was a 5 mile long string of drill pipe that weighted an enormous amount that I forget now but I cheated I used a drilling rig.

And I agree that if you can't tell with your eyeball if you should lift it or not you don't need to be lifting anything at all. These photos of moving a 2500 lb VMC (http://gnipsel.com/shop/unload-308/unload-308.xhtml) might give you a chuckle even though it was done in a safe and controlled manner with only a toe jack and a couple of come alongs.

Thanks for your comments on the gantry.

John

John Stevenson
10-21-2012, 05:15 PM
The only one who could/should design, certify and rate any significant lifting device is an experienced qualified structural/civil engineer.

It must be certified as being "designed to Code" with a certified copy of the Engineer's computations and certification - including his registration details.

"Eye-balling" such things in not "designing" or "rating" them.


From the Tiffiepedia workshop allow us to show you our "designed to code" gantry wheel.

http://www.stevenson-engineers.co.uk/files/Hyd-lift2.jpg

The Artful Bodger
10-21-2012, 05:25 PM
I would be comfortable using BJT's gantry to shift that lathe as I can look at that thing and say "yea, that looks pretty good for the job".

CCWKen
10-21-2012, 06:39 PM
I have no doubt that it can LIFT 6 tons. Moving is a different matter. Shop gantry cranes are not engineered for moving loads. Perhaps you don't realize the center of gravity is at the top of the crane. Moving a raised load and suddenly stopping (like hitting a small screw on the floor) will apply about 10 tons to each of your forward 3-ton casters. Of course, this is based on MY eye-ball estimate of the crane dimensions. And your 100,000 psi bolts don't mean a thing when your design is using 30,000 psi clamps. Your gantry is neither engineered nor certified. But as a great author once wrote; "nothing an intelligent person says can ever be understood by a stupid person". We'll just hear about your failure via the Darwin awards. :(

Here's a clip from a well known gantry crane manufacturer's owners manual. It's engineered and certified. It says it all. (The highlight is mine.)

http://img.photobucket.com/albums/0903/CCWKen/GantryWarnings.jpg

oldtiffie
10-21-2012, 06:44 PM
I've had quite a bit to do with professional engineers and its fair to say that they will almost almost always save their fees - sometimes quite a bit over - in justifying safer stronger (less metal) structures than "eye-balling" as they calculate every member and connection as well as "fitnes for purpose" and "rate" or "certify" it as "complying to code". They "call up" the most efficient use of materials and processes. I'd retain the Engineer to check and certify the job during construction and on completion.

"Over engineering" all too often costs $ in material that is in excess to a good engineering design - and its heavier and more awkward as well.

Say, $200 to $500 (small/medium jobs using a local Engineer) is good value and better peace of mind. It is very handy in case of an insurance claim.

I never let my ego get in the way of getting it done properly.

As a general observation, if it can't be done properly here it either doesn't get done or it gets done by some-one who can - that $ cost soon sorts out whether the job is worth it.

Sometimes there is a very thin line between "eye-balling" - and even claiming to "engineer" it in the process - and is often (but not always) stuff that red-necks and shade-tree mechanics would be proud of.

"Lifting device" collapses or mal-functions can not only be catastrophic but they can happen in an instant with little or no warning.

The Artful Bodger
10-21-2012, 06:50 PM
When we were kids we were never allowed to climb trees until an engineer had checked them out and defined a load bearing rating for every bough.

gaston
10-21-2012, 07:02 PM
sorry. but the dealings I've had with most "engineers" and Lawyers has proven to me , that for the most part they are nothing but over paid bull**** artists.
And neither of them will gurantee the results of there work

oldtiffie
10-21-2012, 07:26 PM
When we were kids we were never allowed to climb trees until an engineer had checked them out and defined a load bearing rating for every bough.

100% opposite here in OZ - then - but we were never "cotton-wooled" and didn't have "hover-craft" parents etc. where pretty well any perceived as opposed to real risk is seen or imagined it is "taboo" today.

I, likeI guess many here, have been figuratively been "out on a limb" many times - sometimes as a calculated risk others as an "arr, bugger it, give it a go anyway, as "she/we'll be right" - but never here in a shop - ever.

uncle pete
10-21-2012, 08:00 PM
LOL,Yeah and the countless and epic engineering disasters that get reported about almost daily haven't ever taken place? Anybody here have any examples of some really piss poor engineering in their homes or cars? I'm certainly not against higher education and specificly engineering. But when the job has to get done no matter what, all you stick to the book and get an engineer to figure everything out and certify it had better never stray off the black top. Engineering no matter how good has failures too. And I thought this was still HSM. I'd certainly trust that gantry design long before I'd trust my "engineered" Chinese built cherry picker at even half it's rated two tons. Has it now become forum decorum to nit pick every single project posted? Next we'll be X-raying or NDT everything before posting about it. Here's a news flash, Even being slightly interested in tools will get you lumped into the redneck and back yard mechanic classification by 90% of the population today. And there's certainly nothing wrong with anyone making the effort to properly engineer their project. In fact I'd admire them for doing so. For most here? That mark 1 eye ball is good enough.

John showed a real good example of how to move a real heavy cnc machine with very simple tools. I can't think of one single engineer I've ever met who could easily do the same. John Stevenson showed a piece of equipment being removed from his shop not too long ago by a certified operator. Again that turned into something that was done that had to be judged as unsafe by a few people who had never done it.

Pete

customcutter
10-21-2012, 08:46 PM
Good Job John, wish I had it in my shop.

I guess I won't be posting pics of unloading my 3000# mill using a come-along, couple of pieces of pipe, and a small model 1920 ford tractor. They'd all have a hissy fit seeing that mill come off the back of the trailer at a 45 degree angle.

Ken

J Tiers
10-21-2012, 09:45 PM
The gantry appears to me to be somewhat overdesigned, if anything..... it has a good tall beam on top, and the columns have what appears to be a good "slenderness ratio". I don't know any of the dimensions, so that is a "visual WAG".

Most of you folks turn into shrinking violets and nervous Nellies when anything like lifting is involved..... And maybe you should.... so don't lift anything... ever.....

I only *know* of ONE qualified individual here on the board, although there may be more. That person is jep24601, and he will probably stay right out of the discussion, a smart move for him.

I am NOT QUALIFIED, I am NOT a structural or civil RPE... so think what you want about what I say.

The exhortation to not have the load suspended when moving the entire assembly are good, but may be NOT FOR THE REASON YOU THINK....

Sure, there is a risk of applying an "undesigned load" to the structure, that is a real potential problem..... but I'd first be worried about the load "taking charge" swinging, and shifting the base around, or banging into other stuff, possibly overturning the whole structure undamaged.

it is excellent advice to tie down the load to the structure when moving it, and I believe the OP actually mentioned that. Setting it on crossbars is another good idea, it converts the whole thing into essentially a "rolling cart", which I assume most, with the possible exception of Tiffie, will agree is much better.

THAT SAID.... there are plenty of lifting devices which lift and move suspended loads. It is DONE EVERY DAY. Yes, they are "designed" to do what they do, but that does not mean heaving up the load and "booking it" off to the new location is OK. Those moves are made slowly, and the surface the crane moves over is smooth and level, in general (think crane-ways in a factory).

it is a rare crane indeed that is actually "designed" to deliberately take a swinging load.... Dragline excavators being one, for instance, and they take that load in a specific direction only.

More generally, the operation is such as to AVOID a swinging load. The reason is so that sufficient energy to cause a problem is NOT put into the suspended load. heavy lift runway cranes move very slowly, something you cannot always guarantee when rolling a gantry on an uneven floor.

if your crane or Gantry is sufficient to lift the load, which can in part be determined from tables of allowable beam loading, and if it is operated in such a way as to not get the load swinging, there is no reason to get all breathless about the "possible" or "potential" dangers. With "Bubba" in charge, those "IF" statements may be a problem.

I have seen the craziest lashups used to lift... usually by mechanics pulling engines. One had a 12 foot span of 3 x 4 I beam, with an unreinforced butt weld near the middle, complete with some visible undercutting/thinning. While I would never recommend these things, I observe that they were used for many years without the obvious deficiencies in the structure becoming a problem. So it is possible to operate a bad system in a way that does not fail.

There is NO SUCH THING AS A SAFE CRANE OR GANTRY. The design may be certified (to please Tiffie), the construction may be approved, but suitable operation and proper maintenance is also required.

And anyone who is under or nearly under a suspended load, and is not absolutely required to be there for a reason of safe operation, is a big fool, whether the crane is certified or not.

Possible problems? Sure... here's a couple that have not been mentioned (AFAIK)

The columns should take only a vertical load, but bending of the beam (less with two point support as in pic) will apply some side force to them via the braces. That will force the lower ends outwards slightly. "Significantly"? Probably not, but we have no data that will let us understand the magnitudes.

The casters will allow an off-center loading......... if in-line with their "arms" there is no bending on the vertical columns, but with casters swung out parallel to the beam, there is an eccentric load applied, tending to bend the beam and force the floor end of the verticals to splay out or in, depending on whether the casters are swung out or in toward the load.

We don't know dimensions, so we cannot judge that possible problem, either. But under some conditions, with sufficiently 'free-rolling" casters, it could be an issue. One more reason (aside from lawyers) to put the instructions to lock the casters in the manuals.

oldtiffie
10-21-2012, 09:58 PM
LOL,Yeah and the countless and epic engineering disasters that get reported about almost daily haven't ever taken place? Anybody here have any examples of some really piss poor engineering in their homes or cars? I'm certainly not against higher education and specificly engineering. But when the job has to get done no matter what, all you stick to the book and get an engineer to figure everything out and certify it had better never stray off the black top. Engineering no matter how good has failures too. And I thought this was still HSM. I'd certainly trust that gantry design long before I'd trust my "engineered" Chinese built cherry picker at even half it's rated two tons. Has it now become forum decorum to nit pick every single project posted? Next we'll be X-raying or NDT everything before posting about it. Here's a news flash, Even being slightly interested in tools will get you lumped into the redneck and back yard mechanic classification by 90% of the population today. And there's certainly nothing wrong with anyone making the effort to properly engineer their project. In fact I'd admire them for doing so. For most here? That mark 1 eye ball is good enough.

John showed a real good example of how to move a real heavy cnc machine with very simple tools. I can't think of one single engineer I've ever met who could easily do the same. John Stevenson showed a piece of equipment being removed from his shop not too long ago by a certified operator. Again that turned into something that was done that had to be judged as unsafe by a few people who had never done it.

Pete

Pete.

I've had "experienced builders" reckon a good engineered design was "too flimsy - never work" - only to be stunned when it did "work" and worked well - some came to discuss it with the Enginer and/or me (I am NOT an Engineer) and were quite decent about it, others were conspicuous by their silence and absense and many would ring the engineer up about advice on other unrelated (non-engineered) jobs for advice on stuff in the job or for better, cheaper methods. It all worked very well. The Engineer got paid for any advice orprofessional work. This Engineer was "100% practical" and would do his best to suit the client or the builder. Many builders were stunned at the difference in (expensive) material between what they'd thought or allowed (for) and others were supprised at how some stuff had to be "beefed up" - and why - as any problems would have been on their own heads - the more so if they had been warned in writing by the Engineer (if a chat on-site or over the phone didn't work).

As a general case, I don't really worry about "cost" as in many of these cases I am more concerned about "value" and "performance" as if that's right its a good investment and a good "cost" too.

I carry very little in the way of "material" and so I buy it locally from a very good supplier - at "trade" prices - so I am careful about what I have to buy.

I don't have - and don't want or need - access to "dumpsters" - as I've had the place cluttered up with stuff that was never used and I had a big clear-out - and off to scrap it went - a lot of it - and I've never regretted it or missed a bit of it.

I agree absolutely that "eye-balling works - with the right people and the right job - and that's fine - but the risk is with those that "designed" or built it.

Once people begin to think they are infallible (God?) irrespective of any requirements or other people it can get anywhere between low and very high risk and dangerous - with a big heap of arrogance thrown in.

Rosco-P
10-21-2012, 10:06 PM
The gantry appears to me to be somewhat overdesigned, if anything..... it has a good tall beam on top, and the columns have what appears to be a good "slenderness ratio". I don't know any of the dimensions, so that is a "visual WAG".

Factors that (as you've observed) that can't be determined from the photos or the posts: wall thickness of the square tubing, this would affect their ability to resist flex and side force; quantity and quality of the welding, is there enough filler, was good penetration achieved. Without any calculations, how could the working load (6T) be determined? What safety factor 2x, 3x, etc. does the gantry have?

J Tiers
10-21-2012, 10:28 PM
Factors that (as you've observed) that can't be determined from the photos or the posts: wall thickness of the square tubing, this would affect their ability to resist flex and side force; quantity and quality of the welding, is there enough filler, was good penetration achieved. Without any calculations, how could the working load (6T) be determined? What safety factor 2x, 3x, etc. does the gantry have?

Considering that all the welding I see is NOT in the direct load "path" of forces, I doubt the welding is a factor so long as it doesn't damage the tubing, which we do not see much evidence of. But of course without X-ray analysis you can't be certain of that......

The search for certainty and absolute safety is bound to be capped with failure.

The parts could stand up and lift the load even if not one piece was welded, which is a good way to design. This does not mean that the welding is un-necessary, simply that the joints are not carrying any non-compression load so long as side loads are zero. It's a bit like a stack of bricks.

Engineered? Signed off by registered engineers?

The Kansas City Hyatt Regency "bridges" across the lobby were signed off by registered engineers..... but they came down and killed or permanently injured a large number of people. The engineers had their registrations rescinded, no doubt a relief to the dead and injured. (Not).

The bridge in Minneapolis was designed and signed off by registered engineers, but got built with defects (steel gussets were half the required thickness) despite inspection.... stood up for a long time, but fell down a few years ago. The design was such as to be totally dependent on every piece being correct, a style which is now being deprecated, despite the number of truss bridges which technically are designed that way, but have stood for decades.

Certification does not mean it is perfect. What certification does is provide a known culprit if there is a problem. This naturally gives the various engineers etc a powerful incentive to be correct in all that they do..... but it does not guarantee that they will be.

oldtiffie
10-21-2012, 10:32 PM
As the topic is about a specifice crane I thought I'd post a (Wikipedia - of course) - general interest item on cranes generally:

http://en.wikipedia.org/wiki/Crane_(machine)

Google:

http://www.google.com.au/search?q=crane+machine&hl=en&rlz=1R2IRFC_enAU360&prmd=imvns&tbm=isch&tbo=u&source=univ&sa=X&ei=AbCEUKToIuWQiAeTt4DgBA&sqi=2&ved=0CFMQsAQ&biw=1920&bih=884

J Tiers
10-21-2012, 10:56 PM
here are some commercially built gantry setups which you should find to be absolutely appalling............ They show many of the "problems" that you all have been bringing up (and some I mentioned)

http://www.aceindustries.com/p-9060-1-ton-adjustable-gantry-crane-12ft-span.aspx?gclid=CJmVw4nPk7MCFUZgMgod62kAqg

http://www.globalindustrial.com/p/material-handling/hoists-cranes/cranes-gantry/steel-gantry-crane-adjustable-height-4000-lb-capacity-1?utm_source=become&utm_medium=shp&utm_campaign=Cranes-Gantry-become&infoParam.campaignId=T9L

http://www.google.com/imgres?imgurl=http://www.low-cost-cranes.com/images/gantry-cranes-4.jpg&imgrefurl=http://www.low-cost-cranes.com/&h=1073&w=1220&sz=55&tbnid=NhSwPvKCuhjPsM:&tbnh=90&tbnw=102&zoom=1&usg=__3TQhyzFRccjLYgdHwDaLWcSnIRU=&docid=TeOMSK726i6EcM&sa=X&ei=3bSEUN7oEOnDyQHzp4DABQ&ved=0CFcQ9QEwBw&dur=2844

http://www.fsindustries.com/more_info/aluminum_gantry_crane/aluminum_gantry_crane.shtml

darryl
10-22-2012, 12:35 AM
JT you are right- I am appalled by all those examples. I would not have any one of them in my shop. I would engineer my own and I can guarantee you it will be safer than any of those- and it isn't ego talking.

I have one comment regarding what Uncle Pete said 'most people here can use the MK 1 eyeball method'. I would say some, but not most. I find that most people, even those with a good set of mechanical skills, don't have a good grasp of structural engineering- being a welder or machinist doesn't make it so. Not knowing the capabilities of the person, the best advise that can be given is to use an engineer. But if you have a good grasp of the concepts, you CAN probably out-engineer, or over-engineer within realistic limits. There is no guarantee that a real engineer will get it right, as has been pointed out, so it's possible that the biggest benefit you'd get would be to have someone for your insurance company to pin the liability on. Personally I would rather apply proper engineering to the thing in the first place-

camdigger
10-22-2012, 03:24 AM
That the safety nannies have managed to prattle on for 6 pages about how safe the OP's crane was and potential liability pitfalls present and future, in spite of it comparing very favorably to commercially available units seems a bit much.

Well thought out and executed John!

John Stevenson
10-22-2012, 04:45 AM
You are missing the main point.
I'm sure than when John T is lifting these machines he's not lifting 10 foot high to go over others.
He''ll be lifting just off the ground to move to a new place and then the centre of gravity will be that low that IF it decided to tip it would just lower the load on the ground and remove any chance of it tipping.

We used to have exactly the same design of gantry when we had the truck garage for removing truck cabs. Some trucks like the Bedford / GM TK series had to have the cab removed to then remove the engine.

This entailed lifting clear which was the full hight of the gantry. Never had any problems lifting or moving.

I am of the opinion that NO lifting or moving photographs should be shown on this site because of the safety Nazi's, most of which have never lifted a machine of any weight in their lives.


For some the most they have lifted is the unabridged copy of tiffiepedia.


But whilst we are on the subject of safety these same people have no qualms about showing photo's of machines being moved on tilt back car trailers and nothing is ever said about them.

Personally I would NEVER use one of these machines as I can see an accident waiting to happen when the forces acting from the centre of gravity have to work thru a tilted angle.

I must admit that I am not a certified engineer but knowing 3 of them I'm pleased as none have a practical bone in their body. I have over a period of time attended 4 courses on recovery of large vehicles from smash incidents, the first two being on tanks and such like by the MoD.
The later two on commercial vehicles and whilst not directly relevant to machines the principles are the same.

camdigger
10-22-2012, 05:02 AM
I have over a period of time attended 4 courses on recovery of large vehicles from smash incidents, the first two being on tanks and such like by the MoD.
The later two on commercial vehicles and whilst not directly relevant to machines the principles are the same.


You are quite right John. To a rigger or equipment mover, your priceless machine tool or possession is just a lump of stuff - often to them, frustratingly poorly balanced. Few have any appreciation of what the machines do, but many are extremely good at moving said lumps without harm to human, buildings, or the machines themselves.

You and I are also in agreement in your assessment of most of the safety nazis aboard. I guess I am an exception. As a PE, I have spent a significant portion of my nearly 30 year career around heavy lifting apparatus... Before that, I spent my youth on a farm doing most of the stuff that would give the safey nazis aboard here the chills and twitches... Like driving a 25 year old farm tractor across a sidehill (gentle one at that) with an 800 lb animal carcass suspended from an old, clapped out, often repaired light duty agricultural loader at full extension. Not a roll cage nor piece of safety gear to be had. Survived without incident repeating this 4 times a year for 15 years....

BigJohnT
10-22-2012, 07:23 AM
This has turned out to be such a fun thread... I can't wait to post some photos of moving my VMC out of the garage and into the shop across the chat covered driveway.

John

Black Forest
10-22-2012, 09:57 AM
I think there should not be any safety warnings or engineers to protect stupid people. Just think about it for a minute. If everything has to be built so that stupid people can't hurt themselves then they live to reproduce. They reproduce more stupid people that need more warnings and engineers to build things so they can't hurt themselves.

Survival of the fittest!

Now BigJohnT is probably not stupid and can figure out quite easily the limits of what is safe and what will work. He built a very good gantry and if he needed something to lift a 3 ton lathe over other machines then he would in all certainty have built his gantry differently.

BigJohnT
10-22-2012, 10:24 AM
Well said my friend.

John

Fireman11
10-22-2012, 11:14 AM
An example of a well engineered lift. Also a timely warning about swinging loads. It is possible to lift and move stuff with sticks and twine and not kill yourself. Make something idiot proof, they will engineer a better idiot.
That said, nice gantry. I would love to have it to move stuff. I wouldn't spend a whole lot of time under a load lifted by it, or indeed any load. Stay safe everyone.
http://www.youtube.com/watch?v=k8RxvyC44yg

mrriggs
10-22-2012, 12:15 PM
What do you think of this one tiffie? http://www.gofastforless.com/junk/emoticons/poke.gif

http://www.gofastforless.com/junk/SafeLift.jpg

BigJohnT
10-22-2012, 12:31 PM
I know what it is and love it!

John

The Artful Bodger
10-22-2012, 03:42 PM
Yeah, that looks fine,:rolleyes: I just hope it goes high enough for the lathe legs to clear the trailer.

What is the fully story?

CCWKen
10-22-2012, 07:48 PM
You are missing the main point. You certainly are!I'm sure than when John T is lifting these machines he's not lifting 10 foot high to go over others.
He''ll be lifting just off the ground to move to a new place and then the centre of gravity will be that low that IF it decided to tip it would just lower the load on the ground and remove any chance of it tippin.

That's exactly where most folks are dangerously ignorant. The CoG will be at the attachment point (The lower point of the beam.) not how far off the ground the load is hanging. Once the load swings off the centerline of the two posts, the posts act as torque multipliers against the bottom legs because the load is pulling from the beam. It doesn't make any difference if the load is at the top or 1" off the ground. In fact, it might be safer with the load pulled to the top. That would keep the swing contained within the span of the casters. (Which is, by the way, too narrow.)

BigJohnT
10-22-2012, 07:56 PM
That's exactly where most folks are dangerously ignorant. The CoG will be at the attachment point (The lower point of the beam.) not how far off the ground the load is hanging. Once the load swings off the centerline of the two posts, the posts act as torque multipliers against the bottom legs because the load is pulling from the beam. It doesn't make any difference if the load is at the top or 1" off the ground. In fact, it might be safer with the load pulled to the top. That would keep the swing contained within the span of the casters. (Which is, by the way, too narrow.)

Why on Earth would you swing the load? You might want to pull a 2 ton lathe to the top but I think your nuts to try that. The COG of the complete rig including the load is still where it is not at the attachment point. The attachment point is only the pivot and why would you pivot a load???? Even when the load is swinging the COG is not at the attachment point.

John

oldtiffie
10-22-2012, 07:57 PM
What do you think of this one tiffie? http://www.gofastforless.com/junk/emoticons/poke.gif

http://www.gofastforless.com/junk/SafeLift.jpg

It obviously "works" well enough but its entirely up to the operator.

I would not use it unless it was certified and rated as per Code.

What would OHS think of it in a commercial environment?

oldtiffie
10-22-2012, 07:58 PM
Originally Posted by John Stevenson

You are missing the main point. You certainly are!I'm sure than when John T is lifting these machines he's not lifting 10 foot high to go over others.
He''ll be lifting just off the ground to move to a new place and then the centre of gravity will be that low that IF it decided to tip it would just lower the load on the ground and remove any chance of it tippin.


That's exactly where most folks are dangerously ignorant. The CoG will be at the attachment point (The lower point of the beam.) not how far off the ground the load is hanging. Once the load swings off the centerline of the two posts, the posts act as torque multipliers against the bottom legs because the load is pulling from the beam. It doesn't make any difference if the load is at the top or 1" off the ground. In fact, it might be safer with the load pulled to the top. That would keep the swing contained within the span of the casters. (Which is, by the way, too narrow.)

+1
................

CCWKen
10-22-2012, 08:21 PM
"Torque multiplier" might have been the wrong term. I should have said "lever".

John - You can't help but swing the load if it's suspended and you're trying to move the gantry. Especially if the gantry suddenly stops while it's moving across the floor. The load will keep going. That's why the suggestion to raise the load then set it down on bars (or something) that are placed across the bottom legs. That will become the new load point, not the beam. And it will keep the load from swinging.

Man, it's like trying to talk to someone that doesn't understand the language. :rolleyes:

The Artful Bodger
10-22-2012, 08:24 PM
The COG of the load is in line with an extension of the supporting cables, if the load swings and the extended line of the supporting cable(s) moves outside the footprint the entire ensemble will go arse up.

There is no bending force on the attachments at the top and bottom of the vertical member while the cable(s) is hanging vertical but this changes if the load swings.

The load will swing if the gantry suddenly stops while being moved, if one wheel of the gantry drops into a hole, if the load is not quite high enough when someone backs a truck under, when some enthusiastic helper pushes on the load etc etc.

BigJohnT
10-22-2012, 08:25 PM
"Torque multiplier" might have been the wrong term. I should have said "lever".

John - You can't help but swing the load if it's suspended and you're trying to move the gantry. Especially if the gantry suddenly stops while it's moving across the floor. The load will keep going. That's why the suggestion to raise the load then set it down on bars (or something) that are placed across the bottom legs. That will become the new load point, not the beam. And it will keep the load from swinging.

Man, it's like trying to talk to someone that doesn't understand the language. :rolleyes:

I understand perfectly, you don't understand I'm not pulling this with my 1956 Ferguson F40 and crap I sweep my floors so what can't you understand that is moved slowly over clean floors and not down my driveway?

John

BigJohnT
10-22-2012, 08:26 PM
The COG of the load is in line with an extension of the supporting cables, if the load swings and the extended line of the supporting cable(s) moves outside the footprint the entire ensemble will go arse up.

There is no bending force on the attachments at the top and bottom of the vertical member while the cable(s) is hanging vertical but this changes if the load swings.


I can't help wondering why you nuts want to swing the load???

John

KIMFAB
10-22-2012, 08:37 PM
Thought I'd jump into the fray here.
I think what the safety nazis here are expecting you to do here is to raise the machine to eye level and run it at 30 MPH to the other side.

If done properly an inch off the floor and slowly walked it will be fine. Excellent setup.
The only problem I can see here is the need for some paint on that OSB siding before it is completely shot. :)

1200rpm
10-22-2012, 08:39 PM
i know after having just an engine hoist, i`d sure like one!
wouldn`t take up much room and would blend in with the decor nicely.

CCWKen
10-22-2012, 08:48 PM
Hmmmm. Ok. Might as well be talking to a rock. See ya.

customcutter
10-22-2012, 08:57 PM
John:

Just make sure you don't use your new gantry while running across the shop with a pair of sharp scissors.;)

Ken

Doozer
10-22-2012, 09:00 PM
http://i72.photobucket.com/albums/i169/kooldoozer/Machines%20and%20Stuff/SDC10993.jpg

This is my gantry that got everybody's panties in a bunch a few years ago.
This pic is lifting my Gorton 9-J which is 3400 lbs.
To add to the mess, Yes I moved the gantry loaded with my machines suspended.
I loaded 20 machines, from 700 to 3500 lbs with this gantry and moving it under load
went smoothly. I had a flat concrete driveway, and that was a help.
I used 8 castors total on this gantry and it is very stable. I believe this helps a lot.

I know most people here think I am nuts. I am eccentric that's for sure.
But I pulled off moving 20+ machines with this gantry and all went very smooth.

http://i72.photobucket.com/albums/i169/kooldoozer/Machines%20and%20Stuff/pictures026.jpg

At my new house I was not so lucky as to have a flat concrete driveway.
I had crushed stone driveway and the front of my garage was on a slope,
about a foot drop in 10 feet. You can see the wood blocks I used to level the feet
of the gantry and plumb the columns in 2 directions. For unloading each machine,
I had to set up and plumb the gantry, pick a machine off the trailer, take down the
wood blocking and move the gantry out of the way, then drag each machine into
the garage, them move the gantry back into position, level and plumb with the blocking
again, and repeat a lift.
I was blocking the one side up at least a foot or more. Used lots of wood blocking.
It was a slow process but I got all my machines moved.

As I said, I know many here don't like my gantry, but I never felt unsafe using it
for what some consider harry stuff (moving it loaded). I mean be careful and don't
do anything you don't feel safe with or don't have experience with. I moved all
my machines within my comfort zone. I have in the past been involved in some
harry set ups, and not always by choice. Even moving a washing machine or a
refrigerator can get catastrophic pretty quick if numbskulls are helping or the
equipment is less than wonderful. I think the key is to go slow and test out any
new equipment or equipment you are not familiar with.
I loaded 3 machines, each over 3000 lbs, in an old cotton mill onto a flat bed
truck with someone else's forklift. The guy just left me alone for a couple of
hours and left me his forklift for me and a friend to load the machines ourselves.
A 1950's Towmotor that I had to hammer on the stater motor to get it to crank,
and we barely got it started. Well, it burned oil like crazy. We were in a low (9ft)
ceiling area and I did not dare shut off the motor for fear it would not start again.
I also did not want to stall the forklift for the same reason. So I very gently worked
the clutch and gears and even had to give it some throttle when I worked the
hydraulics to keep her going. It was like 2-1/2 hours to load these machines, all
the while breathing this blue smoke exhaust! Got the machines out a dock level
(use that loosely) door, all 3 on to the back of a 12 foot Dodge flat bed truck.
Lots of harryness moving at that date. We never had a mishap, but it could have
gone much smoother and safer. Had to work with the situation.
Morale of the story is, make time to be safe and make the proper preparations
to be safe. Only make a lift if you feel all the variables you can manage.
If things happen, learn from it and adjust your approach next time.

--Doozer

mike4
10-22-2012, 09:03 PM
Often when having to dismantle machinery which was installed in a building , I have fabricated temporary structures which were used twice and then removed from site .

The OH&S people on site called us "competant personell " which meant that we knew what we were doing and took full responsibility for the outcome of our actions.

At no time did we go looking for someone to blame , like many here .Just get the faulty part out repair it and re-assemble , test and return to service.

I am talking about equipment which often weighed several tons and we make sure that no one who was not involved in the maintenance was no where around .
Michael

J.Ramsey
10-22-2012, 09:06 PM
Big John, your gantry looks very well constructed and I wouldn't hesitate to sleep under it under load the same as I would the dozens I have built over the last 35 years.
Here's a couple pics of the two Jib's I made for my current shop.

The one in the first pic was used to unload the mill and lathe in the second pic.
http://i.imgur.com/WJPEv.jpg

http://i.imgur.com/0LeRx.jpg

sasquatch
10-22-2012, 09:18 PM
Very good posting Doozer!!

dneufell
10-22-2012, 09:45 PM
huff...huff...huff......sorry i'm late to the party BigJohn T, mrriggs and Dooser ....Thanks for the pics....very nice tools :) Dean

dneufell
10-22-2012, 09:48 PM
oh ya ....jramsey too! Nice Buell. My Dad had a baby one and i rode it a few times.....very cool. Running a Fatboy now....like the 6 speed more than the 96 inch motor :) dean

The Artful Bodger
10-22-2012, 10:47 PM
I can't help wondering why you nuts want to swing the load???

John

I dont recall advocating swinging the load, in fact I strongly advise against it, but then maybe I really am nuts.:rolleyes:

J Tiers
10-22-2012, 10:52 PM
What crazy talk is this about the COG being at the point of attachment at the top ? (that's what it read like)

The COG is nice to know, but what you REALLY want to know is where is the net "pull" direction (force vector) relative to the supports. If everything is sitting still, that's passing through the COG and pointed down. For sure the net pull is going to pass through that point of attachment. (maybe THAT is what was meant by using the term "COG".) So if all is steady, the force vector goes thru the point of suspension, and the COG of the load, which are vertically in line.

But if the load is swinging due to some mishap (nobody we presume, wants it swinging), then the net force will point somewhere other than down. If it points at some direction outside of the supports, AND/OR the COG of the whole works moves outside the base area, the whole thing may tip over and dump the load. (or it may just roll that way, before the force manages to point outside the base)

That would be quite a swing, generally, and we hope nobody would move the load that fast on purpose.... but with non-flat shop floors stuff can happen if the load "takes charge" and rolls on the casters downhill.

Another good reason to not roll the gantry, or at least to have some form of restraint or snubbing to keep it from getting away, since undoubtedly the load is raised so that it can be moved somewhere.....

Using Tiffie's principle... that folks are surprised at the lightweight stuff that really does work.......... since this gantry is built so that most agree it looks solid, then even Tiffie must be agreeing that it will likely be OK, even if he is agreeing in a "backhanded" way.....;)

oldtiffie
10-23-2012, 12:02 AM
here are some commercially built gantry setups which you should find to be absolutely appalling............ They show many of the "problems" that you all have been bringing up (and some I mentioned)

http://www.aceindustries.com/p-9060-1-ton-adjustable-gantry-crane-12ft-span.aspx?gclid=CJmVw4nPk7MCFUZgMgod62kAqg

http://www.globalindustrial.com/p/material-handling/hoists-cranes/cranes-gantry/steel-gantry-crane-adjustable-height-4000-lb-capacity-1?utm_source=become&utm_medium=shp&utm_campaign=Cranes-Gantry-become&infoParam.campaignId=T9L


Using Tiffie's principle... that folks are surprised at the lightweight stuff that really does work.......... since this gantry is built so that most agree it looks solid, then even Tiffie must be agreeing that it will likely be OK, even if he is agreeing in a "backhanded" way.....

I've said before that some folks who "eye-ball engineer" stuff are often inclined to be a bit excessive with the material (and not necessarily good with the joints or connections) and they are often amazed at just how little a good Engineer can design it with - as well as certifying, numbering and "rating" it. Many of the "eye-ball engineers" ridicule them as "not right", "too flimsy", "can't work" etc. but they are wrong on all counts.

Now have another look at the designed cranes that JT posted earlier:

http://www.google.com/imgres?imgurl=http://www.low-cost-cranes.com/images/gantry-cranes-4.jpg&imgrefurl=http://www.low-cost-cranes.com/&h=1073&w=1220&sz=55&tbnid=NhSwPvKCuhjPsM:&tbnh=90&tbnw=102&zoom=1&usg=__3TQhyzFRccjLYgdHwDaLWcSnIRU=&docid=TeOMSK726i6EcM&sa=X&ei=3bSEUN7oEOnDyQHzp4DABQ&ved=0CFcQ9QEwBw&dur=2844

http://www.fsindustries.com/more_info/aluminum_gantry_crane/aluminum_gantry_crane.shtml

Now note the low weight and low cost.

If I needed a crane like that - I don't - I could not see why I should not buy it and further why I should not even think about "eye-balling" it.

Black Forest
10-23-2012, 01:29 AM
Tiffie writes that he wouldn't use anything that wasn't "certified" by a paper carrying expert makes me laugh. I think he doesn't live in the real world or has never actually used any of his book smarts to do any real work in the real world. Yes that is what we call people that have a lot of reading and education but no everyday common sense or experience.

My dad always told me to use my brain and figure things out. Every farm boy knows that if you swing a load it will pull at the top and tip over. He won't know the names of all the forces involved but he will know what is going on and he will get the job done as part of everyday farm or ranching life. If he gets hurt and has no common sense then he goes off to college and becomes an Engineer and tells other stupid farm boys how to do things.

The Artful Bodger
10-23-2012, 01:58 AM
I found this picture on another site...
http://www.gofastforless.com/junk/SafeLift.jpg

...where I also found this comment.....

The strap actually pinched the beams flat which removed all strength and the whole thing came crashing down. Luckily, nobody was hurt.

.....maybe those safety nazis have a point?

John Stevenson
10-23-2012, 04:25 AM
That is what is meant by eyballing a design.

Slotted angle uprights and the orange stuff is the flimsy box section that makes up pallet racking.

Bottom of the slotted angle isn't secured enough and no bracing side to side.

Eyeballing that I'd put a safe working load of 400 pounds on that but static lift only and seeing as it doesn't have wheels then it would be static.

Other thing to consider is we have all moved loads like engines etc on those garage cranes and when they move they are bound to swing.
Also take into account they don't have a wide footprint so can all these flat earthers who say if it swings it will tip over explain why these garage cranes don't seeing as millions must be in every day use.

Tiffie don't answer this, only practical people need reply, no posed photo's, no tiffipedia links, nothing to see move on please.

The Artful Bodger
10-23-2012, 04:55 AM
Other thing to consider is we have all moved loads like engines etc on those garage cranes and when they move they are bound to swing.
Also take into account they don't have a wide footprint so can all these flat earthers who say if it swings it will tip over explain why these garage cranes don't seeing as millions must be in every day use.



Sorry John, I cant explain that at all...

http://shariconglobal.com/misc/hsm/dropped_lathe.jpg

http://bbs.homeshopmachinist.net/threads/54872-HSM-Rigging-Hindsight-is-20-20

oldtiffie
10-23-2012, 05:22 AM
http://www.machinistweb.com/forum/showthread.php?t=776

Many thanks to the person who fowarded the link

J Tiers
10-23-2012, 07:38 AM
Hard to see how the strap "pinched" the beam when there are not one but TWO load spreaders visible.... but with that sort of top beam it is entirely possible.....

They are NOT made for a "point load" but for stacking pallets on, where the pallet has some strength and spreads the load out. And there are two beams per section as well.

As for the other photo, I notice that the lathe is sitting on the upright and good-looking lifter... which obviously did not tip over.... IIRC there was some issue with the load COG and insufficient supports....

mike4
10-23-2012, 09:23 AM
One thing that some forgot , commonsense , many dont have it and others say that it cant be taught .

If you have any doubts as to the capacity of any lifting device , then DONT use it, call in professionals .

Also not too much that we take for granted in life would exist if there were no people prepared to take some risks.

Michael

Black_Moons
10-23-2012, 09:27 AM
Yea, id rate the above wooden crane at around 500lbs max myself and that lathe at 2000lbs, Im amazed it lifted it that high before the wood top beam snaped in half due to being half rotten (Arrr me mateys, I hate wood.. Or at least, don't trust it much)

Also the reason that engine cranes don't tip over easily.. Is because they are on wheels that would much rather move the entire crane under the load, then allow the load to tip over. They only tip when you get some momentium up then hit an obstical it can't clear, then the object swings till the line extending from the pivot point extends past one of the supports (wheels)

John Stevenson
10-23-2012, 09:36 AM
Sorry John, I cant explain that at all...

http://shariconglobal.com/misc/hsm/dropped_lathe.jpg

http://bbs.homeshopmachinist.net/threads/54872-HSM-Rigging-Hindsight-is-20-20


Now read the description on WHY it fell.

It wasn't a crane fault it was operator fault.

mrriggs
10-23-2012, 09:37 AM
Hard to see how the strap "pinched" the beam when there are not one but TWO load spreaders visible.... but with that sort of top beam it is entirely possible.....

The strap pinched the beam the first time I used it. Lesson learned. Now I use the load spreaders and there has been no further drama.


They are NOT made for a "point load" but for stacking pallets on, where the pallet has some strength and spreads the load out. And there are two beams per section as well.


If you look a little closer, you will see that I am using two beams back-to-back. Also, knowing that they are rated for a distributed load, I bought beams rated for [at least] twice what I intend to lift.

Is it safe?

These discussions crack me up. I don't care if "IT" is safe. It is just a thing. If it breaks I throw it away and get another thing. Getting safety approval from engineers and lawyers is a pointless effort.

The real question should be, "Are you safely using it?" This is easy to answer, even for those of us without a degree. If you (a.) do not put any part of your body under a suspended load, and (b.) do not stand in the moving path of [or downhill from] a load, then you are using it safely.

Deja Vu
10-23-2012, 10:03 AM
http://www.youtube.com/watch?v=RAKznfcS6rw

Insufficient top corner/angular supports? Seems like they may have done this successfully before....with better luck, as that is what I see.... pure luck from any previous success.

It appears the COG was not calculated correctly before the load was released from the trailer/platform. But there might have been an unseen obstruction. What do you think?

Stronger angular support at the top just MAY have compensated with enough strength to withstand the shift, but probably not.

MrFluffy
10-23-2012, 10:06 AM
Other thing to consider is we have all moved loads like engines etc on those garage cranes and when they move they are bound to swing.
Also take into account they don't have a wide footprint so can all these flat earthers who say if it swings it will tip over explain why these garage cranes don't seeing as millions must be in every day use.

Tiffie don't answer this, only practical people need reply, no posed photo's, no tiffipedia links, nothing to see move on please.

The machine tends to wag the engine crane when it swings, rather than tip it. Its a lot like watching my big labrador wag his tail and his whole back end gets pulled round when he really gets into it...

While it can be unnerving if you are trying to smoothly guide it into position, I think you'd have to be doing something really stupid to make the crane fall over, because the majority of the force is still downwards due to gravity, so the side to side wag forces are still a very small vector, unless your pushing it at 30mph.

I'd love to have that gantry, for now I have to keep on using my jcb, trailers, engine hoists and the neighbor's telehandler :)

BigJohnT
10-23-2012, 10:50 AM
I was going to say something about the safety Nazis not having a clue about the physics involved because they obviously have never touched anything like this but it seems I've been beaten to the keyboard.

Could I turn it over with a 3 ton load? Yes I could. Would it be easy to do if I operated it in the manner in which it was designed? NO.

With enough velocity and deceleration fast enough for the load you could turn it over. But you seem to forget the fact I can't push that fast...

John

Deja Vu
10-23-2012, 10:58 AM
Just for the record, John. I think your gantry is well built and for you to have a problem you would have to use it in an abusive manner.

BigJohnT
10-23-2012, 11:15 AM
I agree completely.

John

oldtiffie
10-23-2012, 12:17 PM
I forgot to mention that with a Professional Engineer designing a crane or lifting device that many if not most or all times the device is "proof loaded" to at least its "Safe Working Load" (the"working load" plus a %-age of it) at various points along the beam/s to see that the deflection is within or does not exceed the (Engineer's) design limits and that there is no unacceptable buckling or distortion (long and short term).

The proof load is a known weight within fairly tight limits.

As a rough example, if a crane/beam is rated at a safe working load of say 6 tons and its proof load is say 6 x 1.3 = 7.8 tons the beam is loaded to 7.8 tons at each end, at the "quarter", "half", or "third" points (Engineer to
specify).

Many people seem to "rate" the crane at its centre where the end loads are 6/2 = 3 tons, but if the working load is applied at say one end that end will be loaded to 6 tons working or 7.8 tons under proof load.

If a beam fails it may collapse or bend slowly but the crane ends which are columns may collapse very quickly and completely.

The crane is usually rated for vertical loads where as any side load (static or dynamic) may well exceed the limits of the crane and is designed for the intended use and purpose.

Here in Australia in commercial environments where OHS has to approve the rating and use of the crane, the crane must be designed by a professional engineer and re-tested (visual and/or proof) periodically. A crane must be "in test" for it to continue to be used.

Similar principles are applied to pressure vessels (compressor receivers etc.).

The LPG (methane?) cylinder in my car was re-tested recently and came up fine. The tests are carried out when new and every ten years there-after. My mechanic refused to work on the car if it was out of test - so it was re-tested in time and so every thing is fine. A record of the test is fixed to the cylinder.

oldtiffie
10-23-2012, 12:18 PM
I forgot to mention that with a Professional Engineer designing a crane or lifting device that many if not most or all times the device is "proof loaded" to at least its "Safe Working Load" (the"working load" plus a %-age of it) at various points along the beam/s to see that the deflection is within or does not exceed the (Engineer's) design limits and that there is no unacceptable buckling or distortion (long and short term).

The proof load is a known weight within fairly tight limits.

As a rough example, if a crane/beam is rated at a safe working load of say 6 tons and its proof load is say 6 x 1.3 = 7.8 tons the beam is loaded to 7.8 tons at each end, at the "quarter", "half", or "third" points (Engineer to
specify).

Many people seem to "rate" the crane at its centre where the end loads are 6/2 = 3 tons, but if the working load is applied at say one end that end will be loaded to 6 tons working or 7.8 tons under proof load.

If a beam fails it may collapse or bend slowly but the crane ends which are columns may collapse very quickly and completely.

The crane is usually rated for vertical loads where as any side load (static or dynamic) may well exceed the limits of the crane and is designed for the intended use and purpose.

Here in Australia in commercial environments where OHS has to approve the rating and use of the crane, the crane must be designed by a professional engineer and re-tested (visual and/or proof) periodically. A crane must be "in test" for it to continue to be used.

Similar principles are applied to pressure vessels (compressor receivers etc.).

The LPG (propane?) cylinder in my car was re-tested recently and came up fine. The tests are carried out when new and every ten years there-after. My mechanic refused to work on the car if it was out of test - so it was re-tested in time and so every thing is fine. A record of the test is fixed to the cylinder.

Black Forest
10-23-2012, 01:31 PM
Stiffie you are suffering from a bad case of verbal diarrhea. You just like to type and spout off all this engineering crap to hear yourself type. It has been made quite clear that none of us are interested in your postings regarding the legality and engineering of John's gantry crane. He built a good gantry for his needs. He knows how to use it safely so put a sock in your mouth or put your keyboard in a sock.

Most all of who read this agree and have hinted at what a blowhard you are so take the hint. Please.

We are just a bunch of guys getting things done. We don't need no stinkin rules and safety Nazi's raining on John's gantry.

I would suggest you start your own thread regarding all the certification and safety and watch how many views it gets. Besides yourself there won't be many.

BigJohnT
10-23-2012, 01:38 PM
I was wondering why he posted the exact same thing twice???

John

Black Forest
10-23-2012, 01:48 PM
I was wondering why he posted the exact same thing twice???

John

Because he is so impressed with himself that he thought we idiots needed to read it again!

George Bulliss
10-23-2012, 01:59 PM
Looks like we are all in agreement on the subject of gantry cranes, so perhaps it’s best to close this one down and move on to other subjects that we can reach a similar understanding with. Perhaps global warming or politics?