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torque capability of slogging spanner ? 1

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Gerry45

Mechanical
Sep 16, 2002
53
I have a difficult bolting application that might be solved by the use of an open ended slogging spanner. The nuts to be tightened are M36. Does anyone have an approximate feel for the amount of torque that could be applied by such a tool ?

Clearly it alot depends on how hard you can hit the spanner!!!, but there must be someone who has a rough idea as to what can reasonably be achieved. Your comments and thoughts would be most welcome.

Regards,
Gerry
 
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In construction this type of wrench is more than fairly common. It is also appropriate to use the "turn of the nut" method to calculate the torque. Change that to "approximate" the correct torque. Big guy, big hammer, big torque---if you are not careful.

Rod
 
Apologize for my ignorance. What exactly is a "slogging spanner" and what does it look like?

Thanks, Mike
 
That's a soft-faced sledgehammer that's used to pound on the end of a big box-wrench. The torque can be sky-high as evelrod says.
 
Actually, I think "slogging wrench" is called a "slug wrench" in North America. Box end wrenches (variety of larger sizes) with not so much a handle, but an "anvil". I've mostly seen them used for disassembly purposes involving large fasteners. The box end goes over the nut or bolt head in the conventional manner, and a suitably sized hammer is used to strike the anvil to loosen the nut. Anything but a precision instrument, but in those cases where brute force IS the correct answer...
 
A 'Crow's Foot' is very similar to the slug wrench except it has a square hole to receive a ratchet, breaker bar, or a torque wrench. It is generaly used to tighten nuts that cannot be turned using a socket/ratchet because of height restrictions. The crow's foot is a torque multiplyer. (like putting a cheater bar on the end of your wrench(spanner). [smile]
 
Slugging wrenches or hammer wrenches are common in the oilpatch where remote locations don't always allow for power, air or hydraulic wrenches. For a 1-3/8 8UN thread (sort of close to M36X4) you can easily get over 1000 ft.lbs (1300 N.m). You could go a lot higher but at some point the amount of torque gain doesn't equate to the amount of muscle pain.
 
I have always called them "Flogging" spanners.

If possible use a ring spanner, not an open-ended one, as this is less likely to come off the nut when you hit it.

In my experience, you can use this type of spanner to bring Grade 8.8 bolts to the "yield plateau", providing you have a long enough tube to put over the end of the spanner, and a willing helper to turn it for you.

Look in the Snap-on catalogue under "sledge hammer wrenches". Russell Keays
 
I don't know about tightening torque, but I have removed fasteners that just laughed at an impact wrench rated at 2,000 ft-lb of torque. I use a slugging wrench that is about 9 inches long and a 12lb sledge. The slugging wrench allows the use of a breakover bar also, so the fastener is already torqued to 200-500 ft-lb for removal.
 
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