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Discussion Starter · #1 ·

The other day I was tightening my fork triple pinch bolts to 17ft-lbs and I couldn’t help but feel really worried that I was significantly over torquing them. So I started looking into calibration, which professionals can charge up to $60 per wrench to do! Then I came across this video, which uses a handheld luggage scale. Bought one on Amazon, highly rated unit, $12. Yeah not $5. I wanted more reliable accuracy.

Anyway, I tested the scale out today by picking up a 25lb dumbbell; it read 25.2lbs. Good enough for me. Now I don’t have a large enough vice to use the method in the video to check my wrenches, so I just set my wrench to 25ft-lbs, snapped on a 22mm socket, and put it right on the rear axle, which I know is torqued pretty high. Attached the handle of the scale, pulled, and my wrench was easily taking 34lbs to click. Not good at all. I could have been putting 25lbs on the pinch bolts when I only wanted 17lbs. This is a HF 3/8” torque wrench, been dropped dozens of times. So I made some adjustments and now it clicks between 24.5 and 25lbs every time. Got the pinch bolts tightened down to a much more appropriate feeling torque. I will update with further findings on my 1/4” and 1/2” torque wrenches.

Link to the specific scale I bought (I am not an affiliate):
 

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As you get older, you trust that "feel" slot more than a torque wrench. Also, you start to realize some torque specs are more than needed. I use 10 ft lbs for pinch on forks. And for axles, I'll actually spin the tire. Fork spacing between upper, lower and axle are affected by torque and a spinning tire or fork stiction can be affected not only by torque, bout in the order torque is applied.
 

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Nice find!
 
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I didn't watch the video, but be sure to compensate (do the simple math) for handle length if it is anything but one foot... remember that you are measuring lbs-ft of torque.

Years ago, I used to teach the metrology course for the US Navy at the Bangor submarine base.
 

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Discussion Starter · #6 ·
I didn't watch the video, but be sure to compensate (do the simple math) for handle length if it is anything but one foot... remember that you are measuring lbs-ft of torque.

Years ago, I used to teach the metrology course for the US Navy at the Bangor submarine base.
Yeah in the video he goes all into measuring the length and compensating so you get an accurate measurement of foot-pounds.
 

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Another easy way is to tell the snap on tool truck person that if he can prove your torque wrench is more than 10% out of spec you'll buy the fancy new angle one...
I did that and it worked out great, love my fancy new AngleTech 😂.
 

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Another easy way is to tell the snap on tool truck person that if he can prove your torque wrench is more than 10% out of spec you'll buy the fancy new angle one...
I did that and it worked out great, love my fancy new AngleTech 😂.
It's TechAngle, not AngleTech. $575 for a 3/8 drive adjustable from 5 to 100 ft lbs.
 

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It's TechAngle, not AngleTech. $575 for a 3/8 drive adjustable from 5 to 100 ft lbs.
Go ahead and play with your little one...
215533
 

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Yeah my $10 one from Harbor Freight is now +-5%..
Lol, that's what got me in trouble. Snap on was shooting off about how inaccurate anything but snap ons was and blah blah blah. My big mouth hands him my 5$ flea market wrench from the early 1300's and says bs i bet you that new wrench that this POS from the flea market is within 10% of that thing. If you win i buy one, if you lose i get your wrench. I didn't think he'd go for it tbh... And that's how I paid too much for something i didn't really need. Keeping your word can get expensive sometimes.
 
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Of course one must understand that torque is an indirect method of measuring bolt tension and is highly variable to the coefficient of friction inherent in the thread and the K factor of the lubricant. You can have the most accurate torque sensing device in the world and still be off by 30% on the actual bolt preload, particularly with dry thread installations. It's so important to follow manufacturer lubrication spec or find the equivalent.

There is a reason torque to yield headbolts were invented, as it is a direct indication of bolt tension.

Snap-on wrenches are now pretty good. Not because they are Snap-On, but because they are re-branded CDI tools; as they bought the company 10 or so years ago. Pre CDI, meh.

When I used to calibrate torque wrenches, I found the click type torque wrenches to fail initial calibration most often. Dial types rarely failed.

Angle type torque wrenches make a lot of sense, but I don't have a lot of hands on work with them. I have however calculated and performed many turn of the nut bolt tensioning. Makes a heck of a lot more sense than torquing.
 
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