doing head gasket job, and was wondering if using a reducer and a 3" or 6" extension is going to change the actual torque of the wrench, compared to the actual reading.
I'm using a clicker type

I have read on the web so far, that using an adapter or extension (to reach the bolts on the bottom of the head for example) does not affect the wrench. I'm looking for second opinions.

 

Depends on your definition of accuracy! If you are using a short 3" to 6", 1/2" drive extension, it's not going to make any appreciable difference. This is easy enough to check, just torque 4 bolts with the extention and 4 without. When go back and recheck. Obviously if you start going to longer thinner extensions, like a 3/8" drive, that 18" long your probably going to have some loss of torque at higher reading.

 

It will not affect torque. Draw a free-body diagram, and you will see that although a longer/thinner extension might deflect in torsion, the torque applied to the bolt will be identical to the torque applied to the extension by the torque wrench. Just make sure you keep the axis of the extension in line with the axis of the bolt.

 

the only way torque will be affected is if you extend the handle of the wrench

 

I don't see how that's possible. You'd still be applying the same amount of torque to the bolt. A longer handle would just give you more leverage to generate that torque and hence it will be easier to turn.

 

what? extending the handle? if a device is placed between the head if the wrench and the bolt, you need to do math to find the correct torque to set the wrench to to get the desired torque at the bolt


however, just using a normal length extension, no, you will not loose any

 

ha - good point

 

You'll be fine with or without the extenstions. Don't worry about it.

This thread is drifting to a fine discussion on the short comings of the traditional torque wrench and it's applications. Personally I prefer a daily calibrated DC nutrunner with speed, torque, and angle control.