Gang,

Question regarding the math on a torque wrench.

I have a 1/4 Torque Wrench which is in Inches/Pounds.
But, a lot of specifications are in FT/LB.

Can I still use an Inch/Pound wrench (since 12 inches = a foot) or is it better to buy a FT/LB wrench.

I hope this makes sense, I'm trying to do the conversion in my head.

Thanks!

 

i for one would buy a ft lbs wrench. i do not think you would be able to. use an inch lbs wrench if you need to torque to 105, ft lbs like on the rear axle.

 

You are right - 1 ft lb = 12 inch lbs.

I like to use the wrench where the torque value is near the middle of its range. I wouldn't want to use inch-pounds at the extreme constantly. Barring frequent check and calibration - middle of the range is my target.

 

Yes, your idea of "multiples" would work in theory ... but ... Buy a foot pound torque wrench and give the inch pound wrench a break before you break it.

 

Proper torque wrench size requires torque to be applied to be between 1/3 and 3/4 full range of the torque wrench.
ie... A 100 in/lb wrench should only be used for torques between 33 and 75 in/lbs.

 

wow, you guys are really awesome. Thanks for the quick replies. I know we BS on here alot but when real questions comes up, I really appreciate the serious responses. I was having a hard time wrapping my mind around the conversion.

I have the 1/4 inch/pound wrench. But I suppose I'll just buy ft/lb wrenches also. The last thing I need is to strip a bolt due to trying to math theory.

Thanks guys.

 

Just a small addition: torque wrenches are manufactured to be accurate (to their rated specs) from 20% of their full range up to 100% of their full range and they are usually calibrated in that range. You'll find that a lot of torque wrenches don't even have graduations or setting marks below 20% of their full range figure.

A torque wrench that breaks or snaps on reaching it's torque setting relies on lubrication, springs and a couple of sliding metal surfaces. They work best if exercised before use - either at the setting they're about to be used or at their maximum setting. If you can break them on a static bolt or exercise plate 6 times before use you'll get the most even results.

Also, always store it at the lowest setting, wipe it down after use to keep the whole thing clean, and try not to drop it.

 

What about calibrating? Does anyone here actually calibrate their wrenches- and if so, how?

 

Yes, they need to be calibrated. The tool truck guy of your choice will send them in and have it done. I recently did all three of mine, the 250lb was fine, the 150lb needed adjustment and the incher was junk and had to be replaced. these were all quality well cared for name brand tools. I do not remember what it cost, the defects were that they read "low"

 

I find the tekton cheapo wrenches from Amazon at about 40 are good for a year or two, then need replacement. However snap on's at several hundred still need cal after a couple years, which will cost about the same as a new tekton. Fwiw.