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crane uprate - where would you add some metal ?

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gerry madden08/02/2021 18:59:26
212 forum posts
104 photos

I bought this small engine crane for lifting things in the workshop and garage a while back. Its rated at 200Kg and 500Kg at maximum and minimum extensions of the jib.

So far this capacity has suited my purposes very well. However one day i may need to lift something heavier so before that time comes I might undertake a little project to add a little more robustness.

I haven't done any calculations on it yet but before I do I thought I'd ask the structural stress experts here where from experience (bitter or otherwise) they might be inclined to beef it up a bit ?

My first thoughts are the rear wheels !

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Jim Nic08/02/2021 19:16:37
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358 forum posts
202 photos

Interesting first thoughts Gerry.

As someone who had an interest in lifting equipment in a previous life, my first thoughts are - Dont Do It.

If it's not man enough for the lift you want to do get a bigger crane.

Jim

JasonB08/02/2021 19:21:29
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Moderator
21632 forum posts
2493 photos
1 articles

I might look at the ram first, no point in beefing up the structure if you can't get it to lift more weight.

John ATTLEE08/02/2021 19:32:29
19 forum posts

Don't even think about it. That crane will be designed so that everything is only just strong enough for its task. Keep your crane for what it is good at. If you need to lift something heavier, hire the right equipment for the job.

John

Tony Pratt 108/02/2021 19:53:24
1757 forum posts
8 photos

The crane will have enough all round metal to do it's job but not a lot more so don't do it.

Tony

not done it yet08/02/2021 20:07:17
6438 forum posts
20 photos

You should not be getting any advice on how to lift more than its capacity. When you have a crumpled heap of scrap to deal with, and possibly injuries, would you be thanking those that gave you the advice on ‘how to do it’?

Get a tool with sufficient capacity for the job is my advice.

old mart08/02/2021 20:08:20
3411 forum posts
210 photos

I would not recommend any modifications.

We have an identical one at the museum with the Seeley brand on it, and we managed to break it. One of the volunteers was lifting something and hadn't noticed that the gib was caught up and couldn't move as expected. He continued pumping and the main arm just outboard of the end of the ram bent until it had a 30 degree bend in it. The inner black tube also started to bend. No other damage was done to it fortunately. It just folded without doing anything else any harm. If the ram had burst, we might not have been so lucky. Our crane had a reinforcing strip already on top of the red part of the arm.

Spares from Seeley were easy to obtain and not expensive. We are more careful with it now. The bits are in my metal stock and have donated some offcuts from time to time.

Bazyle08/02/2021 20:45:32
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6081 forum posts
221 photos

The advantage of the bigger 1 ton crane is it has folding legs so ends up being more convenient to store which is how it spends most of its life. I am looking to use it in its folded form as the basis of a lifting sack truck.

old mart08/02/2021 21:16:39
3411 forum posts
210 photos

Now you mention folding, Bazyle, our museum one folds and the gib can point straight down to take up less space.

Derek Lane08/02/2021 21:40:23
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568 forum posts
112 photos

As already said leave alone all the materials in a crane like this are tested above the stated weight and then given the best lift capacity as stated on the crane. A little like a boiler tested above safe pressure so I am sure you would not run it at what the test pressure used.

I have seen a few machines that were used over and above their safe working labels many fortunately did not incur any injuries. I use to work as an tool mechanic ranging from simple drill up to diggers so you can imagine what people do with machines.

Stay safe and keep it as is and hire a heavy lift crane if needed for the odd job

Martin Kyte08/02/2021 21:58:58
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2608 forum posts
45 photos

Take it outside. add increasing weight to the hook. Reinforce anything that bends, breaks or buckles.

During the second world war they did the opposite with aircraft so I'm told. Any aircraft that came back severely shot up they analysed and reinforced all the bits that were intact on the basis that the bits that were destroyed were not so important. I'm sure they were a little more scientific about it but that was the gist.

Seriously if you are really going to exceed the design spec by modification you should at least do a failure test afterwards so you have some idea of the capacity.

regards Martin

Alan Waddington 208/02/2021 22:11:09
523 forum posts
87 photos

Am always a bit suspicious of engine cranes, a lot claim to be capable of lifting 2 tonnes......yeah right.

I bought a commercial vehicle one for peanuts, no one wanted it because it was stupidly huge. Rating fully closed 2800kg, and fully extended 800kg. The thing is seriously beefy
Donated it to a pal who cut it up and attached it to the back of his tractor. To give a sense of scale the mill in the pic has a 56” bed, and the tractor is approaching 6 tonne

Advice to the OP would be don’t bother, if you need something heavier duty, just buy one,no point compromising safety.

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Martin Kyte08/02/2021 22:39:51
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2608 forum posts
45 photos

I'd be a bit wary of having that tractor on my nice blockwork patio too.

regards Martin

Alan Waddington 208/02/2021 22:50:35
523 forum posts
87 photos
Posted by Martin Kyte on 08/02/2021 22:39:51:

I'd be a bit wary of having that tractor on my nice blockwork patio too.

regards Martin

Tractor didn’t cause any issues, but the concrete waggon a few years prior did. chucked some boards down to spread the load, but the tight turn through the gates did some damage.

Bill Dawes08/02/2021 22:57:59
494 forum posts

I would say the weakest component is the jib which is subject to bending forces. The resultant force in the upright will be tensile so will have greater stength than bending resistance in the jib, but taking into account the ram power and its fixing point at the bottom, the resistance to splaying of the feet, strength of the castors etc etc, I go along with the others, don't do it, theoretically it could be done but you would finish up making a new one, not worth the effort or risk.

Bill D.

Bill Dawes08/02/2021 23:01:41
494 forum posts

The etc etc does of course include strength of the lifting chain and hook, shear strength of the section where the chain is attached to the jib, etc etc.

Bill D.

Paul Lousick09/02/2021 00:37:11
1868 forum posts
666 photos

Gerry,

Modiications will depends on how much extra you want to lift and unless you do stress/bending calculations on all parts of the crane, you will just be guessing. The existing members have probably been selected to just carry the load specified to keep production costs at a minimum.

The maximum downward force is directly under the hook and there will be more load on the front wheels than those on the rear. Best to buy a bigger crane if you want to lift heavier loads.

Paul

John Reese09/02/2021 03:05:00
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1000 forum posts

Listen to those telling you to leave it alone. Ignore all the other advice.

Cranes like you have are designed to be just strong enough to pass regulations. If you do any modifications you relieve the manufacturer and the vendor of any liability should you be injured using the crane.

John Olsen09/02/2021 03:25:53
1215 forum posts
92 photos
1 articles

If you need to lift anything heavier than the standard amount, work around the problem by avoiding lifting it. This can sometimes be done by taking the item into separate pieces and lifting them one at a time. Otherwise get the item up onto steel bar rollers just an inch or two in diameter, and roll it. If it is not up, it can't fall down. You can move an amazing amount with three or four rollers and a few pry bars. If it is over gravel or grass, you will need some steel sheet of a good thickness to spread the load. I've shifted my 18 inch Alba shaper like this

If you do need to get something higher, say to get it onto a bench, you can sometimes do it by building a pigsty out of short lengths of timber. You lever it up one side at a time, and slip a piece of timber in, then the opposite side. The next two go in at right angles, and you build it up to the height you need.

Particular care is needed with top heavy items like lathes and some mills, which love to fall over.

There are some highly educational videos on Utube and the like showing how well gravity works when you get things wrong. Look for crane failure videos.

John

Pero09/02/2021 04:19:06
146 forum posts

Gerry

I have a crane very similar in appearance to the one in your picture. The main difference is that mine is rated to  2 tons with minimum jib extension.

The main difference between the two is size - everything is bigger ( and heavier ) The metal tubes are all larger in cross section with much increased wall thickness, the ram is much higher rated and even the wheels and axles are larger and stronger. It also has a brace on the back ( red ) part of the jib.

To upgrade the 500 kg version to this specification would mean a total re-build ( basically throw it away and start again ).

Having had one for some decades, for my use, which is very infrequent, I would have been much better off hiring the specific lifting apparatus needed for the job in hand, your requirements may differ. In practice mine sulks, in pieces which is the only way I can store it, in a corner and threatens to injure me every time I walk past it.

My comment on heavier is also pertinent. The last time I assembled the crane I found that the weight of the individual components ( legs, jib etc. ) was starting to get toward my limit of lift. Always something to think on as one gets older.

The other problem with the bigger crane is longer legs - very awkward to use unless you have a very large and open shed to work in - mine is now way too cluttered for the crane to be used indoors.

My recommendation, if you can justify having one on hand, would be sell your current one a buy a larger model. The cost of the change over would probably not be much greater the up-rating your present with the subsequent risks that entails.

An alternative that I have considered in the past is to acquire ( or hire ) a manual pallet stacker. These have the advantage of a relatively small footprint - if you have a bench to park the forks under when it's not in use - and can lift a significant weight ( up to 2000 kg for some models ) up to very useful heights ( more than 2 m in some cases ).

Best of luck whichever option you go for.

Pero

Edited By Pero on 09/02/2021 04:20:23

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