Heavy duty C clamps

I have a question about "heavy duty C clamps". By these, I do not mean regular clamps, but ones with extremely thick (in relation to their
length) bodies. They are much heavier than would be required to simply hold some parts together to be welded, or worked on. Those must have some special uses, and I cannot think of any.
Examples
https://www.armstrongtools.com/catalog/products.jsp?groupID 96
The one below is the one I am looking at (cleaned up one today), it seems to be a poor man's press:
http://www.drillspot.com/products/331473/Wilton_27208_Extra_Heavy_Duty_C_Clamp
With the load capacity of 27,500 lbs, it can develop 12 ton force.
Who would need that in a clamp?
Have you ever needed one?
i
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Lifting steel plates and bars as well as flipping them over with chains and a hoist.

Yes, but they are still dangerous as hell. I only used the things enough to get handling holes drilled and tapped.
JC
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Seems scary. On a second thought, another use for them would be straightening things.
i
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wrote:

chains and

Working with heavy plates, they are rarely dead flat, so need pullling together for welding, rivetting etc. With a 1" plate you need a good strong force to get them snug.
AWEM
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wrote:

It was and I bought a lifting magnet as soon as I could aford one.

We also used them to clamp work to big angle plates on our horizontal boring mill. You don't generally straighten things in a mold shop.
JC
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No one I know would use such an expensive clamp to lift with when a plate clamp is so much cheaper, safer, and dependable. They must have other uses. Personally, I have used big C clamps to draw plates together. You weld dogs onto the plate to clamp the steel. Have also used cut wedges and L shaped dogs.
Steve
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Obviously, higher quality, more heavy duty clamps are less likely to flex when being used at reasonable clamping pressures.
Durability.. it's not likely to wear out, ever, if used below it's rated capacity.
A flexing C-clamp is about worthless, as many are, that are commonly seen in stores. If a common, light duty C-clamp isn't being used on wood or other soft material, it's easy to overtighten them to a point where the C frame is sprung from flex.
For a cheap heavy duty C-clamp, buy an imported ball joint press kit. That's about as heavy a C frame as you'll find. The kit I bought was over $200 less than the referenced Wilton clamp. Better yet, but not cheap.. buy a quality brand name domestic tool maker's ball joint kit, which is likely to be a higher quality alloy, not cast iron.
If space isn't a problem, there are accessory C frame attachments available for 10-ton Porta-Power cylinders.. I've got one, and it looks like a 10-ton micrometer when assembled. It weighs considerably more than the 20k lb capacity Armstrong clamp that weighs 10lbs.
--
WB
.........
metalworking projects
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wrote:

It's the answer to the question of how you keep bridge girders in place while welding/riveting them.
Stan
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On Sun, 17 May 2009 00:02:44 -0500, Ignoramus8051

Yes, I have. And was happy as a bird when I found 4 of them I could use fr the job!
Gunner

"Somewhere a True Believer is training to kill you. He is training with minimum food or water,in austere conditions, day and night. The only thing clean on him is his weapon. He doesn't worry about what workout to do--- his rucksack weighs what it weighs, and he runs until the enemy stops chasing him. The True Believer doesn't care 'how hard it is'; he knows he either wins or he dies. He doesn't go home at 1700; he is home. He knows only the 'Cause.' Now, who wants to quit?"
NCOIC of the Special Forces Assessment and Selection Course in a welcome speech to new SF candidates
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On Sun, 17 May 2009 00:02:44 -0500, Ignoramus8051

This is a heavy clamp...
http://www.suscom-maine.net/~nsimmons/news/BigClamp.jpg
The little one is an Armstrong.
--
Ned Simmons

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Nice picture.
i
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