Torque Wrenches and Extensions.
Thread Starter
|
Senior Member
Joined: Sep 2009
Posts: 3,031
Likes: 45
From: The Shenandoah Valley
Torque Wrenches and Extensions.
No tool or shop sections that I see? I've seen questions come up about the use of torque wrenches with drive extensions and offset crows feet and beam extensions and effects of same and so I thought this might help others.
If not, a moderator can simply delete it.
Here's a good read on Torque Wrenches:
http://www.algeo.com/~joe/KIAT/kiat_3.htm
And this one is worth adding to Favorites for it's plug in tables. Sometimes an extension might come in handy as well as knowing how it changes effective torque at a setting / reading.
http://www.freeinfostuff.com/TorqueE...eExtension.htm
And as to socket extensions .... see page 5 of this document.
http://buy1.snapon.com/products/torq...NET%20SITE.pdf
Also, I have this saved from a post I made some dozen years ago. It explains the use of drive extensions and a torque wrench very well I think.
Imagine using a rubber band versus a wire with two hooks to pull a 10 pound weight across your table. Both will pull it, both take the exact same "Force", but the wire doesn't stretch, the ryubber band will stretch as it stores "Energy". Once moved though, that "Energy" is still there in the rubber band, and the exact same "Force" is required to move the weight. You just had to move your hand further as you moved it, but it wasn't any harder to pull. The extra travel of your hand required you to expend more "Energy" but that "Energy" is still there stored in the rubber band after the pull.
An impact wrench uses "Kinetic" energy from "hits" to tighten a fastener, an extension will store part of that kinetic energy when it recieves it ... and then release that energy between each hit. Thus some of that "Energy" never reaches the fastener. That's how "Torque Sticks" work.
But you take that "Torque Stick" and use it as a socket extension with your old 1/2" drive beam or clicker torque wrench where you pull on a handle and apply "Force", it'll twist, but the torque applied at the wrench drive is the same as that applied to the socket, but you have "energy" stored in the "T-Stick" waiting to unwind as soon as you let it.
Energy and Force are two different things.
"Horse Power" is "Energy" ...
... and "Torque" is "Force".
Take a 1/2" nut and bolt, chuck bolt in vise, use beam TW and T-stick and tighten nut to 50 ft/lbs. Now, remove T-stick, check torque with same beam TW.
If not, a moderator can simply delete it.
Here's a good read on Torque Wrenches:
http://www.algeo.com/~joe/KIAT/kiat_3.htm
And this one is worth adding to Favorites for it's plug in tables. Sometimes an extension might come in handy as well as knowing how it changes effective torque at a setting / reading.
http://www.freeinfostuff.com/TorqueE...eExtension.htm
And as to socket extensions .... see page 5 of this document.
http://buy1.snapon.com/products/torq...NET%20SITE.pdf
Also, I have this saved from a post I made some dozen years ago. It explains the use of drive extensions and a torque wrench very well I think.
Will using socket extensions change torque wrench settings or applied torque?
No.
This has been argued for years and a drive extension will not change the torque value. It does not matter if the extension flexes (winds up) as you would simply pull the wrench farther around.
It is a simple law of physics, whatever force you input into one end of that extension is what is going to be exerted on the other end ... period. If you were getting less energy out of it than you put into it where on earth does that energy go then? If the extension twists then the wrench would simply require that much more movement as it is moving. When the torque setting is reached and movement is stopped then at that point the input force and the resistance is equal and that is what it will read.
Now if you allow the extension to lean over from the center of the fastener so that the wrench turning center is no longer centered over the fastener then you would get an erroneous reading because of the leverage factor, but this is something else entirely. For this same reason a crows foot extension must be compensated for and some wrenches include a chart for doing this but again this is for leverage because the wrench is not centered over the fastener.
No.
This has been argued for years and a drive extension will not change the torque value. It does not matter if the extension flexes (winds up) as you would simply pull the wrench farther around.
It is a simple law of physics, whatever force you input into one end of that extension is what is going to be exerted on the other end ... period. If you were getting less energy out of it than you put into it where on earth does that energy go then? If the extension twists then the wrench would simply require that much more movement as it is moving. When the torque setting is reached and movement is stopped then at that point the input force and the resistance is equal and that is what it will read.
Now if you allow the extension to lean over from the center of the fastener so that the wrench turning center is no longer centered over the fastener then you would get an erroneous reading because of the leverage factor, but this is something else entirely. For this same reason a crows foot extension must be compensated for and some wrenches include a chart for doing this but again this is for leverage because the wrench is not centered over the fastener.
An impact wrench uses "Kinetic" energy from "hits" to tighten a fastener, an extension will store part of that kinetic energy when it recieves it ... and then release that energy between each hit. Thus some of that "Energy" never reaches the fastener. That's how "Torque Sticks" work.
But you take that "Torque Stick" and use it as a socket extension with your old 1/2" drive beam or clicker torque wrench where you pull on a handle and apply "Force", it'll twist, but the torque applied at the wrench drive is the same as that applied to the socket, but you have "energy" stored in the "T-Stick" waiting to unwind as soon as you let it.
Energy and Force are two different things.
"Horse Power" is "Energy" ...
... and "Torque" is "Force".
Take a 1/2" nut and bolt, chuck bolt in vise, use beam TW and T-stick and tighten nut to 50 ft/lbs. Now, remove T-stick, check torque with same beam TW.
Last edited by tbear853; Dec 18, 2011 at 08:16 PM. Reason: I discovered where the quoted part came from .... I wrote it in a reply on another thread in a motorcycle forum in 1999.
Global Moderator &
Senior Member
Senior Member
Joined: Aug 2007
Posts: 7,887
Likes: 61
From: Among javelinas and scorpions in Zoniestan
TBear - nice post! I've copied it over to our "How-To" section, so it will have a "permanent home".
Thanks for helping to make our site the useful resource that it is.
- Jack
Thanks for helping to make our site the useful resource that it is.
- Jack
Thread Starter
|
Senior Member
Joined: Sep 2009
Posts: 3,031
Likes: 45
From: The Shenandoah Valley
I saw that when I found an old messge link in my files and went to update it, thought I had lost my mind, was sure I couldn't post there when I tried. Just now saw it still here.
