Does using a 3 inch extension on a torque wrench have any bearing on the amount of torque applied? This is your standard 3" extension attached to the socket at a right angle to the wrench, it is not extending the overall length of the wrench. The manual for the wrench (Craftsman) gives a formula to recalibrate the wrench when using extensions, but it looks like they are just adding length (L) to the wrench, which I know will change the torque. T = F x L
i don't believe so since as you stated the torque applied is from the length of the wrench not how far it is from the pivot point
but what can be an issue is if you don't keep the entension straight when you torque the bolt down
It has an effect/affect, but with a 3" extension you are talking a minimal one at best. If you are talking about lug nuts, I wouldn't worry TOO much, but if we are talking about rod bolts well then I would def use the conversion table.
Yah, when they mean distance they mean length from the pivot point to the end of the handle. An extension going down onto the lug nut shouldnt make eny differance b/c that length does matter. Although the force woulod go up a little bit because there is more mass.
In reality it shouldnt matter.
Dan
yeah, as stated that calc. is for adding length to the handle.
the only real effect you would notice with a socket extension on the wrench would be under large loads where the extension itself would twist axially.
Thanks to everyone who replied. All of you make good points about adding an extension to a torque wrench. I didn't think there was much to worry about since I wasn't adding length. I just wasn't able to find any conversion calulators for my application. If it was critical, I would guess using a deep well socket would make a difference.
And yes, I was just torquing lug nuts. Call me anal.
Originally posted by Coolkuehl3:
Thanks to everyone who replied. All of you make good points about adding an extension to a torque wrench. I didn't think there was much to worry about since I wasn't adding length. I just wasn't able to find any conversion calulators for my application. If it was critical, I would guess using a deep well socket would make a difference.
And yes, I was just torquing lug nuts. Call me anal.
You're anal!
Maybe I'm mis-reading these posts , but IIRC , adding length to the HANDLE of a torque wrench will NOT make any difference to the torque readings the wrench gives you , it will just add leverage & make it easier on your arms to reach the desired torque . The torque at the head of the wrench , is the torque at the head of the wrench whether the handle is 6 inches or 60 inches . Adding an extension to your socket , however , WILL change the torque reading . A 3" extension will not change the reading much at all , but a long extension will change it much more .
Originally posted by Buddy Palumbo:
The torque at the head of the wrench , is the torque at the head of the wrench whether the handle is 6 inches or 60 inches .
I have to disagree with you on this thought. The formula for torque is T = F x L. T = Torque, F = Force, L = Length. The length is the distance from the center of the socket to the end or grip of the handle. Therefore solving for T and leaving everything the same but changing L will give you different answers.
Example 1. F = 15, L = 16
T = 15*16
T = 240
Example 2. F = 15, L = 8
T = 15*8
T = 120
Example 3. F = 15, L = 24
T = 15*24
T = 360
Originally posted by Coolkuehl3:
Originally posted by Buddy Palumbo:
The torque at the head of the wrench , is the torque at the head of the wrench whether the handle is 6 inches or 60 inches .
I have to disagree with you on this thought. The formula for torque is T = F x L. T = Torque, F = Force, L = Length. The length is the distance from the center of the socket to the end or grip of the handle. Therefore solving for T and leaving everything the same but changing L will give you different answers.
Example 1. F = 15, L = 16
T = 15*16
T = 240
Example 2. F = 15, L = 8
T = 15*8
T = 120
Example 3. F = 15, L = 24
T = 15*24
T = 360
Yes, but that's not how a torque wrench works. The torque wrench stops torquing whenever the torque exerted at the head exceeds whatever is dialed in. Put a 10' extension on it if you want, it will still stop at the same torque spec, it'll just be really easy for you to exert that force.
EXACTLY my point , Sigma !
Now , if you're using a "dogbone" , then the torque reading WILL change .
The longer handle just reduces the amount of force you have to apply to reach a given torque setting. The longer handle gives you more leverage, allowing you to do the same amount of work with less effort.
Originally posted by sigma:
Originally posted by Coolkuehl3:
Originally posted by Buddy Palumbo:
The torque at the head of the wrench , is the torque at the head of the wrench whether the handle is 6 inches or 60 inches .
I have to disagree with you on this thought. The formula for torque is T = F x L. T = Torque, F = Force, L = Length. The length is the distance from the center of the socket to the end or grip of the handle. Therefore solving for T and leaving everything the same but changing L will give you different answers.
Example 1. F = 15, L = 16
T = 15*16
T = 240
Example 2. F = 15, L = 8
T = 15*8
T = 120
Example 3. F = 15, L = 24
T = 15*24
T = 360
Yes, but that's not how a torque wrench works. The torque wrench stops torquing whenever the torque exerted at the head exceeds whatever is dialed in. Put a 10' extension on it if you want, it will still stop at the same torque spec, it'll just be really easy for you to exert that force.
I stand corrected. But if you extend the length from the pivot point, will it change the torque? That is what the manual refers to in recalulating.
If you were to apply the same amount of force to the long handle that you did to the short handle, and if there were no mechanism in the head of the wrench to regulate that torque, then yes, you would have more torque applied at the head. Just remember that that equasion is probably assuming a simple pivot point and lever, not a torque wrench with its regulating internals.
Originally posted by IRingTwyce:
If you were to apply the same amount of force to the long handle that you did to the short handle, and if there were no mechanism in the head of the wrench to regulate that torque, then yes, you would have more torque applied at the head. Just remember that that equasion is probably assuming a simple pivot point and lever, not a torque wrench with its regulating internals.
bingo. That's the answer right there folks! If it was a wrench extended, then applied torque would be greater as proportional to length of extension and also the direction of applied torque. CCW=+, CW=- torque. Keep in mind also that if your line of action is perpendicular to your pivot, then you apply zero torque, just force. That has nothing to do with this, but it's nice to flex our brain muscles on the internet to increase our net-egos from time to time! 
Er... what exactly is a "dogbone"? A regular crescent (box)wrench?
Um, guys, if I'm reading the original post correctly, he wasn't talking about extending the length of the handle, but about adding a standard extension between the torque wrench and the socket.
In this case, yes, you will lose some small amount of the applied torque, because some of the torque will go into the twisting of the extension, because it will basically act like a torsion spring. The general rule of thumb I've always followed is keep the distance from the tq wrench to the fastener as short as possible, and when you must use an extension, raise your applied torque a little bit; usually I'll lean toward the higher end of the spec of whatever I'm tightening when that is the case.
Originally posted by Rara:
Um, guys, if I'm reading the original post correctly, he wasn't talking about extending the length of the handle, but about adding a standard extension between the torque wrench and the socket.
...
LOL. I missed that too when I read it. Thanks for opening my eyes.
Originally posted by IRingTwyce:
If you were to apply the same amount of force to the long handle that you did to the short handle, and if there were no mechanism in the head of the wrench to regulate that torque, then yes, you would have more torque applied at the head. Just remember that that equasion is probably assuming a simple pivot point and lever, not a torque wrench with its regulating internals.
equa t ion. 
Do I win a prize? 
Tx
No offence, but couldn't resist....
Or for our US brethren, No offense. 
Originally posted by timstour:
Originally posted by IRingTwyce:
If you were to apply the same amount of force to the long handle that you did to the short handle, and if there were no mechanism in the head of the wrench to regulate that torque, then yes, you would have more torque applied at the head. Just remember that that equasion is probably assuming a simple pivot point and lever, not a torque wrench with its regulating internals.
equa t ion.
Do I win a prize?
Tx
No offence, but couldn't resist....
Meh...It was late, I was tired, and it's hard being perfect 100% of the time. I think 99.9% perfect is good enough for me!
Originally posted by Rara:
Um, guys, if I'm reading the original post correctly, he wasn't talking about extending the length of the handle, but about adding a standard extension between the torque wrench and the socket.
In this case, yes, you will lose some small amount of the applied torque, because some of the torque will go into the twisting of the extension, because it will basically act like a torsion spring. The general rule of thumb I've always followed is keep the distance from the tq wrench to the fastener as short as possible, and when you must use an extension, raise your applied torque a little bit; usually I'll lean toward the higher end of the spec of whatever I'm tightening when that is the case.
Brian - this is exactly what I was getting at , when I joined in on the conversation .
This is a dogbone . It's a pretty crude pic , but it does the job .
"A" is the torque wrench
"B" is the dogbone
Where "A" & "B" meet is where the square-drive is on your torque wrench (i.e. - where your socket attatches) .
The hexagon at the left of the dogbone is where you'd hook it to the nut/bolt you wish to torque .
Here is the formula for figuring out the proper torque generated by the dogbone extension :
Using (once again)
A = length of torque wrench
B = lengthe of dogbone adapter
C = torque wrench actual setting
D = desired torque at nut/bolt
There are many ways to make/use a dogbone , but the result is the same - you can torque something far above the limit of your torque wrench by using one . Extending the length of the handle does NOT . Once the torque wrench clicks/beeps , torque is reached , job done .