Effects on torque reading
Effects on torque reading
(OP)
OK here's the delema. I have to develop a torque wrench extension to reach a bolt under a verical. What I have come up with is a box end extending horizontal for 3 inches and then 90 degrees down for 6 inches to the torque wrench. My problem is what will the reading on the wrench be @ 51.6 lb ft on the bolt. It's been a long time but I don't think I'm that rusty. I can't seem to come up with a factor to adjust that isn't dependent on the length of the torque wrench being used.
Someone shed some light on this for me (I know I'm going to kick myself!!)
jwj
Someone shed some light on this for me (I know I'm going to kick myself!!)
jwj





RE: Effects on torque reading
Torque1 x ArmLength1 = Torque2 x ArmLength2
therefore
Torque2 = Torque1 x ArmLength1 / ArmLength2
RE: Effects on torque reading
What is the bending moment in a cantilever length L at a distance x from the encastre wall ?
What is the torque at the tip of the cantilever, where a pure force is being applied?
Cheers
Greg Locock
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: Effects on torque reading
RE: Effects on torque reading
Now if you replace T with Force applied (F) the shorter lever arm will require higher applied force to reach the torque I can live with that as long as Delta (F) off sets the factor of Delta A1/A2. Follow
RE: Effects on torque reading
If you set a torque wrench to a setting it will click off at that setting, however due to the elasticity in your torque arm it may affect the pre-load in the bolt.
regards
desertfox
RE: Effects on torque reading
So, T=F1*L1=F2*L2=F3*L3=.....Letting L1 be the original length of the wrench and L2 be the new length of the improvised wrench then the new force F2=T/L2=F1*L1/L2.
Only the force and length change for the required torque.
The torque remains constant for whatever length "cheater" is being used. So if the requirement is 40 ft-lbs, when a "cheater" is added , that value must still be maintained on the torque wrench.
By the way OSHA will cite any employer for home made and unauthorized cheaters
RE: Effects on torque reading
Sorry, I have either completely misunderstood your explanation or it ignores the OP's idea, which places the torque wrench's measuring axis part way along the lever.
Cheers
Greg Locock
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: Effects on torque reading
I think Chicopee and myself read the op's question as just adding length to the torque wrench arm and not that he was
moving the position of the torquemeter measuring axis
regards
desertfox
RE: Effects on torque reading
Cheers
Greg Locock
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.