I need to do some car maintenance and removing the plugs can take a lot of torque to remove. If I put a 1/2” to 3/8th adapter on my 1/2” breaker bar, do I lose torque? For some reason, it seems to me like I would but I can’t put my finger in why.
I don’t think you lose any static torque, but the play in the connections will definitely reduce impact torque.
I didn’t know there was more than one kind.
When you are bearing down on the breaker bar by hand, and nothing is moving, that’s static torque. If you are using an impact wrench, which is banging away at the bolt, that is dynamic torque.
I actually just had this happen to me today. There was a tiny bit of give in the adapter and it made the impact wrench useless, as it was just slapping the socket against the adapter really fast. I reconfigured the thing without an adapter and it instantly gained enough torque to take out the bolt.
I learned the difference today, too. Thanks @beowulff!
In my use case, it won’t be quite that bad as the plug I need to remove is just a 3/8ths square so I don’t need a socket.
@beowulff is correct that the loaded static torque will remain the same regardless of the size or number of adapters, not accounting for misalignment. The addition of an adapter may add some flexure, and you’ll have some additional ‘play’ depending on how tight the connections are; because an impact wrench or driver is applying torque in a series of very brief impulses you will find that it is less effective because so much impulse is lost in this flexure and takeup. For that reason, you want to avoid using adapters and long extensions on an impact wrench. For a static condition using an adapter with a breaker bar, your main concern is not overloading and breaking the smaller drive head.
Stranger
This is similar to what a “torque stick” does. By introducing some compliance between the impact wrench and the nut/bolt, it absorbs some of the impact from the wrench and reduces the peak torque delivered to the nut/bolt. Torque sticks are designed with different lengths and diameters to provide different limits on peak torque. If a mechanic twists a wheel stud off of your car, chances are he was tightening your lug nuts with an impact wrench and without a torque stick.
To lose torque in that situation, wouldn’t some thing have to deform?
Adding adapters does not change the length of the moment arm, so you neither gain nor lose any torque. It is exactly the same. But as others have said, the slop in the connections of the adapter will lessen the efficiency of the force applied to the breaker bar.
Changing the interface size because some of your tools are 3/8 or 1/2 (or 1/4) isn’t the issue. Increasing the length of your handle/bar does decrease the torque. This isn’t normally an issue if you’re removing a fastener, but if you’re using an actual torque wrench to tighten, you need to calculate the adjusted torque if you change the length.
This video shows that and give the math for it.