djkeev
Well-known member
I've got an older vintage Craftsman Foot Pound click style torque wrench.
I've used it for almost 20 years and haven't ever had it calibrated, who has the time or cash???.
Anyway, I've always released the tension after using it but with my Son In Law living here now.......he doesn't.
I thought I should check out the accuracy, not going to spend any $$'s........shade tree style.
I found this web site....
http://www.srtorque.com/Downloads/Instructions/857313D.pdf
For my math.
My wrench handle pull sweet spot is 16 3/4" from the center of the 1/2" drive.
I have two 15 1/2 lb bags of dog food, total 31 lbs. I checked them on a scale, very close to the package posted weight.
So I tied the two bags together with twine, similar to what we used to do with newspapers back in the day for recycling. I left a length of string and made a loop to hang on the handle.
I clamped the 1/2" square of the wrench in my vise, removed the plastic handle end cover to access the adjustment screw (11/16" thin wall deep socket and a 7/32 Allen wrench) I loosened the jam nut and hung the dog food bags off of the handle.
Doing the math..... To get the torque multiply the handle length (16.75) times the weight of the dog food (31 lbs).
16.75 x 31 = 519.25
This is inch pounds, divide by 12
519.25 / 12 = 43.2708333333
In other words 43 foot lbs. I set the click dial to 43 lbs.
I adjusted the Allen screw until the weight of the dog food made the wrench click. It took a few tries but finally I dialed it in. Using my 11/16" socket only, I slipped the Allen wrench through the square to hold the threaded rod still and used a pair of pliers on the exterior of the socket to tighten the jam nut.
I doubled checked it with the dog food..... Viola' .....perfect!
I wondered, is it right? So I got out my old beam ft lb wrench, put that in the vise, hung the dog food at 16 3/4" and guess what it read? 43 lbs!
I Love it when a Rube Goldberg solution works!
Dave
I've used it for almost 20 years and haven't ever had it calibrated, who has the time or cash???.
Anyway, I've always released the tension after using it but with my Son In Law living here now.......he doesn't.
I thought I should check out the accuracy, not going to spend any $$'s........shade tree style.
I found this web site....
http://www.srtorque.com/Downloads/Instructions/857313D.pdf
For my math.
My wrench handle pull sweet spot is 16 3/4" from the center of the 1/2" drive.
I have two 15 1/2 lb bags of dog food, total 31 lbs. I checked them on a scale, very close to the package posted weight.
So I tied the two bags together with twine, similar to what we used to do with newspapers back in the day for recycling. I left a length of string and made a loop to hang on the handle.
I clamped the 1/2" square of the wrench in my vise, removed the plastic handle end cover to access the adjustment screw (11/16" thin wall deep socket and a 7/32 Allen wrench) I loosened the jam nut and hung the dog food bags off of the handle.
Doing the math..... To get the torque multiply the handle length (16.75) times the weight of the dog food (31 lbs).
16.75 x 31 = 519.25
This is inch pounds, divide by 12
519.25 / 12 = 43.2708333333
In other words 43 foot lbs. I set the click dial to 43 lbs.
I adjusted the Allen screw until the weight of the dog food made the wrench click. It took a few tries but finally I dialed it in. Using my 11/16" socket only, I slipped the Allen wrench through the square to hold the threaded rod still and used a pair of pliers on the exterior of the socket to tighten the jam nut.
I doubled checked it with the dog food..... Viola' .....perfect!
I wondered, is it right? So I got out my old beam ft lb wrench, put that in the vise, hung the dog food at 16 3/4" and guess what it read? 43 lbs!
I Love it when a Rube Goldberg solution works!
Dave