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Larry
You are correct. Using your example, at 12" the applied force required is 64lbs. The three inch extension will experience 80 FT-LBS of torque. Your math example assumes a torque wrench that is calibrated at 12 inches. The problem arrises when Tim (380mxc) has a torque wrench that calibrated at 22.57 inches. Torque = force X distance For a 12" torque wrench with a 3" extension, setting 64 FT-LBS results in 80 FT-LBS at the bolt. 64LBS x 1.25feet = 80 FT-LBS For the 22.57" torque wrench with a 3" extension, setting 70.56 FT-LBS results in 80 FT-LBS at the bolt. A force of 37.23LBS at 22.57 inches (1.88feet) = a torque of 70.56 FT-LBS Adding a 3" extension to the equation. 37.23LBS x 25.57 inches (2.13feet) = 80 FT-LBS Tim can't just multiply torque required by .8 and plug that into his torque wrench. His torque wrench manual values line up with the extension formula. Wrench torque = Torque Spec * (Wrench length / (Wrench length + extension length)) |
Mike,
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--Paul |
Now what was for sale?:eek:
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In the video the wrench appears to be made of 2 thinner pieces based on the appearance. is it? Or is it one piece with a line around it? Thanks Marty
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This is supposed to be a prop wrench, how 'bout a prop service bulletin for reference?
http://www.mccauley.textron.com/sb227B.pdf, see the last page. |
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dial reading = torque wrench length (ft) x desired torque (ft lbs) / [torque wrench length + extension length (ft)] Clearly this falls into "the 0.8 multiplier is not a constant" camp. Im back to not knowing what to think. Could this SB really be wrong? erich |
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As I said before, show me the math and I'll be a believer, but I still haven't seen it. All ft pound wrenches are not 1 ft long which is what this "theory" is based on. If every torque wrench was 1 ft long then Allen would be right, end of story. |
Allan,
Looks like the Retail Price of your wrench has gone up... include a 12" 3/8" drive Snap On high quality torque wrench in the wrench kit and then nobody will have the need to do the math. :D |
Take 3 torque wrenchs, one 1 ft long one 2 ft long and ine 3 ft long. All are calibrated for 100 ft lbs torque.
So even though they are different lengths, they all put exactly the same 100 ft lbs of torque at the head. So all three torque wrenches put exactly 100 ft lbs of torque at the head and then you add the exact same 3 " extension to them. Wouldnt the 3 " extension have the same effect on the 100 ft lbs of torque at the head on all of them? Just saying...:D |
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