NinerBikes wrote:
wnjj wrote:
Huntindog wrote:
wnjj wrote:
Huntindog wrote:
wa8yxm wrote:
Your 3 foot crows foot will add as much as 1.2 feet to the length of the wrench at a 90 degree angle or to be more precise it will add Sqrt(18)-3 feet That is for a wrench with a 3 foot handle,, the relationship is for those math inmpaired is
Sqrt = Square Root
Sqrt((Handle^handle)+(extension*extension)) if it's 90 degrees
Example if the extension is 3 feet, the handle 4, the overall effective length is five.
Put me in the math impaired camp...:B That's Ok though as I knew that other thinking had to be wrong. Often times if one "grows" a line of thought,,, it becomes obvious what the right answer is.
With regard to this side topic:
The length doesn't change at all if you apply the force perpendicular to the wrench handle. By definition, torque is the force applied at a perpendicular distance and that is still the length of the wrench if the crowfoot is 90 degrees to the wrench.
The calculation above only comes in to play if you push perpendicular to the imaginary line between the wrench handle and the bolt. In that case the torque applied to the bolt will increase. The reason is the same force applied perpendicular to the wrench will cause the wrench to reach its value as the non-crowfoot case. By pushing at an angle to the handle some additional force is being applied straight down the handle endways. This additional force acts to rotate the crowfoot without being measured by the wrench.
The end result is the bolt has more torque applied to it than is measured my the wrench. It matters little what angle the crows foott is at.
Read my post again. The potential to end up with more torque on the bolt is there but ONLY if you push incorrectly on the handle. If you push perpendicular to the wrench, the torque is correct.
Don't you still add "moment of arm" compound leverage, just the same as you do adding a cheater bar for additional length and leverage at lower pounds pressure at the end of the length of an extension, for the same amount of torque?
You add the "effective" moment arm which is the amount of length you gain along the same line the torque wrench follows. In the case of 90 degrees, that additional moment arm is 0.
Here's a good diagram with equation. Note that at 90 degrees, L = It.
http://firetrucksandequipment.tpub.com/TM-9-254/css/TM-9-254_92.htm
