Torque wrenches

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davidmiller

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Hello I need a wrench for steel beams but thought someone on here might know.
So it needs to be 248 Nm. Thats way higher than Screwfix do so any ideas where to get one and any other points I might need to know? Many thanks.
 
www.screwfix.com

DeWalt Torque Wrench 1/2

Order online at Screwfix.com. Has a rubber bumper on the head to protect during use and in case it is dropped. Forward and reverse torque capabilities and a quick-release trigger to make adjustment easy. 72-tooth ratcheting mechanism with 5° arc swing gives accessibility in tight areas. Supplied...
www.screwfix.com
 
248 Nm is 248N on the end of a bar a metre long. 248N is (in round numbers) a 25kg weight on the end of a metre long bar (or 50kg on a half metre long bar, or 183 lbft in "old money", which, again, is 183lb on the end of a foot long bar or 92 lb on a 2 foot long bar... and so on. I've never cashed-out on a big torque wrench for wheel bearing jobs, because it's just so easy to stand on a bar of the correct length to apply the right torque. The bar just needs to be more or less horizontal when you finish tightening.
 
Thanks everyone, Ive got a few to choose from now havent I. Sounds like I might have my work cut out as the steels are ceiling height.
 
Avocet said:
248 Nm is 248N on the end of a bar a metre long. 248N is (in round numbers) a 25kg weight on the end of a metre long bar (or 50kg on a half metre long bar, or 183 lbft in "old money", which, again, is 183lb on the end of a foot long bar or 92 lb on a 2 foot long bar... and so on. I've never cashed-out on a big torque wrench for wheel bearing jobs, because it's just so easy to stand on a bar of the correct length to apply the right torque. The bar just needs to be more or less horizontal when you finish tightening.
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Very interesting. This is the sort of thing I print off and nail to my garage wall for future reference. That said, is it not rather a profound pain in the gonads to continually bugger around with metre long bars and various weights etc? Also some of those torque wrenches do look rather smart. For instance I am tempted to dive for the credit card and nab one of these. I reckon I would mount it on my living room mantlepiece.
 
chainsaw_masochist said:
Very interesting. This is the sort of thing I print off and nail to my garage wall for future reference. That said, is it not rather a profound pain in the gonads to continually bugger around with metre long bars and various weights etc? Also some of those torque wrenches do look rather smart. For instance I am tempted to dive for the credit card and nab one of these. I reckon I would mount it on my living room mantlepiece.
Click to expand...
LOL! Yes, I like shiny tools as much as the next guy - especially Snap-On! However, I'm not a man of substantial means, and I think the response needs to be proportionate to the task. With something like a modern wheel bearing, the massive torque is to make sure the bearing races are pressed tightly together. But the manufacturer (of both the car and the bearing) doesn't know exactly how much friction there is going to be between the bearing inner races and the stub axle, or the nut and the threads, or the underside of the nut and the washer (or whatever it bears against). Accordingly, he just vastly over-specifies the thread size and calls up a mahoosive torque which is bound to give "plenty" of clamping load in the bearing inner races. The bearing manufacturer, in turn, will size everything so that it will work fine with "a lot" of torque applied to the nut.

My breaker bar is about 0.6m long, and I weigh about 110kg, so I could apply 650Nm if I stood on the end of it. For 250Nm, I'd just stand on the bar with one foot, so that the middle of my foot was about 9" from the centre of the hub nut, with the bar roughly horizontal when the nut stops turning.

One thing I should add, however, is that I do possess two smaller torque wrenches! A 50% overload on a wheel bearing won't bother it, but some of the bearing caps on my cams only want 7Nm. Here. I can't do my "weight x distance" thing, because the bar would need to move horizontally, for a start, but also because +/- 50% would either strip them or leave them dangerously loose. So I'm a big fan of torque wrenches for smaller fasteners!
 
Avocet said:
LOL! Yes, I like shiny tools as much as the next guy - especially Snap-On! However, I'm not a man of substantial means, and I think the response needs to be proportionate to the task. With something like a modern wheel bearing, the massive torque is to make sure the bearing races are pressed tightly together. But the manufacturer (of both the car and the bearing) doesn't know exactly how much friction there is going to be between the bearing inner races and the stub axle, or the nut and the threads, or the underside of the nut and the washer (or whatever it bears against). Accordingly, he just vastly over-specifies the thread size and calls up a mahoosive torque which is bound to give "plenty" of clamping load in the bearing inner races. The bearing manufacturer, in turn, will size everything so that it will work fine with "a lot" of torque applied to the nut.

My breaker bar is about 0.6m long, and I weigh about 110kg, so I could apply 650Nm if I stood on the end of it. For 250Nm, I'd just stand on the bar with one foot, so that the middle of my foot was about 9" from the centre of the hub nut, with the bar roughly horizontal when the nut stops turning.
Click to expand...

Whatever, that’s a decent explanation and your method sounds entirely plausible,. In contrast, though, whilst I try to do most maintenance jobs on my motor, wheel-bearings I would tend to leave to the garage. I always feel that the torque loads required here might shake the car of its axle stands. Utter nonsense, of course but I recognize that the pros would have access to air-powered wrenches and they will complete the job with far greater ease.

Avocet said:
One thing I should add, however, is that I do possess two smaller torque wrenches! A 50% overload on a wheel bearing won't bother it, but some of the bearing caps on my cams only want 7Nm. Here. I can't do my "weight x distance" thing, because the bar would need to move horizontally, for a start, but also because +/- 50% would either strip them or leave them dangerously loose. So I'm a big fan of torque wrenches for smaller fasteners!
Click to expand...

Oddly, I have found that both of my TWs pose problems when wanting to apply lower pressures rather than greater. I am thinking here of a water-pump that I replaced for a neighbour’s son a couple of years back. Such items, I guess, are invariably an alloy cast so the torque rating was low – around 10Nm? - and, clearly outside the scope of my wrench. So I just went hand-tight and half a turn with the spanner. No annoying seepage so it seemed to do the trick. Might try to obtain a low-range TW at some stage, though. Might refrain from the Snap-On, though.
 
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