Torque and Torque wrenches

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Martin Benade
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Re: Torque and Torque wrenches

#31 Post by Martin Benade »

No apologies needed, I love that you got down in the weeds and gave us some fairly real numbers. Thank you!
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Joris Koning
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Re: Torque and Torque wrenches

#32 Post by Joris Koning »

Martin Benade wrote: Thu Nov 24, 2022 3:51 pm No apologies needed, I love that you got down in the weeds and gave us some fairly real numbers. Thank you!
+1 thanks for sharing
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Jacques Lefriant
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Re: Torque and Torque wrenches

#33 Post by Jacques Lefriant »

Hi Dave
Harlan's comment was biased by Hirth Roller crank lore. since roller selection could be made in .00004 increments and the crank had to be assembled to determine the journal size. it is interesting that the cranks were assembled using a bench that determined the torque by the formula using a hydraulic cylinder and pressure gauge at a fixed distance the bolt position was marked. if subsequent assembly was performed using unmarked parts the angle method was used to determine the final tightening.
j
 

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John Hawkins
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Re: Torque and Torque wrenches

#34 Post by John Hawkins »

Jacques mentioned "lubrication is an important consideration". So, do you guys lubricate your fasteners prior to torquing them, and if so with what? What about fasteners where you use Loctite or similar products, do you consider Loctite a form of lubrication?
Just curious,
John

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Harlan Halsey
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Re: Torque and Torque wrenches

#35 Post by Harlan Halsey »

I use engine oil on Porsche parts as I think that was recommended or usual practice at the time. Carrillo rods come with a tube of moly grease. Where I use Loctite, by default that becomes the lube.
For the vast majority of fasteners where I don't use a torque wrench, I use Anti seize. I never assemble a threaded fastener dry.
Actually, my journal growth information came from Dema Elgin with reference to the 356 flywheel joint. Back in the 60s some race engines with bad flywheel connections were unbelievably over torqued to try to get one more race out of it.

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Jacques Lefriant
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Re: Torque and Torque wrenches

#36 Post by Jacques Lefriant »

Hi
another nuanced aspect that comes up in this discussion is the breakaway torque of a fastener, it is not equal to the initial torque so don't think the tire guy over torqued your lug nuts/bolts. Also if you are checking the torque on say head nuts it is best to relax them first.
j
Last edited by Jacques Lefriant on Mon Nov 28, 2022 12:20 pm, edited 1 time in total.
 

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Harlan Halsey
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Re: Torque and Torque wrenches

#37 Post by Harlan Halsey »

+1
There's more to torquing fasteners than pulling on a wrench, and even more to using a torque wrench. Torque is the force generated by a force couple. In practice it takes two hands to torque a faster with a torque wrench if the readings are to be meaningful. And of course, sliding friction is different than static friction. It is important that certain fasteners get consistent torque, particularly cylinder head studs. Competent mechanics and competent amatures know these things.

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Rudy Bernhard
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Re: Torque and Torque wrenches

#38 Post by Rudy Bernhard »

Handy reference. Note K values are explained in the notes, based on bolt coatings, and lubricants.
https://www.fastenal.com/content/merch_ ... 0Guide.pdf

As Harlan noted, for a torque wrench to give a proper value, the two handed technique can be used to stabilize the torque wrench over the joint to insure the handle on the wrench stays perpendicular to axis of the fastener. For larger torques using bigger wrenches, the two handed technique may not be practical. Do what you can to minimize poor joint configuration. Avoid anything that can lead to the socket not being perpendicular, like an unsupported socket extension being used.
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Martin Benade
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Re: Torque and Torque wrenches

#39 Post by Martin Benade »

Harlan, what is the two handed method? I’ve only used a second hand as a fulcrum when using an extension. I believe that is two errors at once.
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DaveErickson
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Re: Torque and Torque wrenches

#40 Post by DaveErickson »

I use a two-handed method, which I suspect is similar to Harlan's. when tightening a right hand thread, I apply a bit of force to the far end of the torque wrench with my left hand while tightening with my right. It stops the torque wrench from twisting and does not affect the torque applied. It is more important when using an extension. With the ¾" drive torque wrench it doesn't work, since both hands are needed to tighten. Using a socket that fits the nut tightly helps avoid the problem.

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Harlan Halsey
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Re: Torque and Torque wrenches

#41 Post by Harlan Halsey »

The point is that unless you are supporting the fastener end, you are putting both a bending force or other side load plus a torque on the joint. You only want the torque. To that end, an extension is an advantage.

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Martin Benade
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Re: Torque and Torque wrenches

#42 Post by Martin Benade »

I thought extensions and two hands both threw off the accuracy. I looked into it and saw a video of guy demonstrating that about four feet of extensions and two hands didn’t have any ill effect. I’ll have to ignore what someone told me 50 years ago.
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