An Extension on a Torque Wrench??

Can you use an extension on a torque wrench? Does that affect the torque output enough to worry about? I'll run through some basic tests to try and come to a conclusion.
The result may surprise you!
This is not a scientific test, just some guy messing around in his garage.

[@stevens3169]

He got more extension than AT&T

[@Dartmech]

😂

[@Kitteh.B]

I never subscribed to the "you can't use an extension with a torque wrench" idea but I DEFINITELY expected all those combined extensions to throw the torque out of whack. Pleasantly surprised at the outcome lol

[@Dartmech]

I was surprised as well! One or two, no problem, but didn’t expect the outcome at all. Thanks for watching!

[@FerdinandAkin]

This testing is for static torque measurements. The torque is the same at both ends, unless there is dynamic rotational motion. If there is no motion, where else can the applied torque go?

[@SoloRenegade]

for anyone saying you cannot use an extension with a torque wrench.... 1) blatantly false (whether you'll get the exact value you were after or not is a Separate issue) 2) I'd like to see those people get a torque wrench into a number of places it's required to torque things...

[@Dartmech]

It was pretty close to the exact values, and in some instances you MUST use an extension for access. Thanks for watching!

[@SoloRenegade]

@@Dartmech I didn't want to summarize your video, so left that bit out.

[@Dartmech]

Ha, whoops..

[@samd8054]

this was awesome, thanks for filming the test we wanted! I'm sure theres a calculation to find the exact inch-lbs lost, but we're not building micron precise clocks out here

[@kenjay3490]

Only rotational displacement will vary. PROVIDED there is NO additional friction at supporting points. Torsional energy will remain constant.

[@Dartmech]

Great comment! I agree. Friction plays a huge part of course, but the main twist (without additional friction) will be consistent with an extension.

[@233kosta]

It's mainly to do with shifting the rotational axis, which in turn changes how the forces are applied to the mechanism act on said mechanism, breaking the assumptions made at the design stage. If you support the head correctly it's fine. Still a little bit out, but well within tolerance of whatever it is you're doing (unless, I guess, you're assembling a jet engine or something).

[@immanutt4442]

@@233kosta that's what she said ...

[@matts4244]

Super well executed and through. Thanks. For the helpful info!

[@Dartmech]

Glad you enjoyed it!

[@kongito4485]

Honestly the 11ft monstrosity is a good way to visialize why extensions dont affect torque, it takes more effort becuase you have to take up the slack but once its out you get the torque you set the wrench to. Now if you did that with an impact you'd definetly lose torque becuase they apply torque in blows not as a constant force. Anyway the only risk you have with long extensions is having angle introduced which will throw off torque readings.

[@snap-off5383]

In order to twist-bend a bar of metal each side must impart identical torque. If not, it will spin in space.

[@bayoumike544]

I know a guy that went to training with a tool manufacture and did a test with a solid extension and a spring type flexible extension and found no difference in torque. Change in torque has always been a myth. All that has been done is taking up slack.

[@Dartmech]

Interesting!

[@immanutt4442]

Thanks for debunking this ol' rumour

[@alb12345672]

Impacts may have a huge difference though.

[@Dartmech]

I'd say so because of the "shock" effect, it might be delayed at the end of a long extension.

[@alb12345672]

@@Dartmech That is exactly how torque sticks work. They "swallow" some of the torque. Impacts don't operate on static torque. They use impulse and momentum to create torque. Very High torque is created for a very small instant in time, so it can't propagate to the fastener.

[@immanutt4442]

@@alb12345672 that's what she said ...

[@wrichardwilliams]

Genius! I often wondered about this. Great video.👍

[@Dartmech]

Glad it was helpful!

[@Fk8td]

It’s bs you can’t use an extension on a torque wrench. You can’t use an extension on a torque stick using an impact gun. The extension will simply twist until the full torque is applied. Adding a wobble extension can create an issue cause you can change the angle.

[@jblcontrol28crossover76]

Some dynamic forces come into play with a torque stick and impact gun. The stick acts as a torsion spring. Maybe that spring action is the source of the "no extensions" rule?

[@Dartmech]

I wonder about the wobble and am kicking myself for not including it in the testing. However, as long as the "twist" remains constant I'm thinking it'll have a similar affect.

[@tomchapman4826]

on a impact that strikes to turn the socket each junction absorbs the striking force. That is the not the case here. However I have twist a snap on 3/8 12" extension with a craftsman 3/8 ratchet by hand

[@james10739]

With that many and depending on the torque maybe because i have seen long expansions flex like a whole 1/4 turn on a like 2 foot expansion

[@tuffytoys9707]

I believe that "Tools Tested" KZbin channel did a test of torque wrenches and it was discovered that the "Icon" brand which you used in the video was usually out of calibration by that 1-3% as you have tested and shown. So in my opinion I would just add 1-2 additional ft pounds to the manufacturer recommended torque value and use deep or short sockets or even a 3 inch extension so long as it is not a "Critical Bolt" like engine head bolts or camshaft rocker bolts etc, anything else it's quite ok.

[@Dartmech]

Ohh thanks for the comment, I’ll check out that channel! Usually 1-2% isn’t much on non critical bolts like you said, but adding one or two ft lbs would be a good idea with that one.

[@TroyCraft]

I thought extensions were fine, but cheater bars (anything that increases length of lever) is problem. ….that’s what a crows foot does- changes length of lever.

[@Dartmech]

Yes, even hand placement will affect the applied torque.

[@Glenn_123]

Thank you so much for doing these videos! Here is a question. Suppose i am attempting to do a spark plug (or any given scenario close to this). I take the spark plug socket place an extension on it to get it out of the spark plug hole. Then use the torque adapter with my rachet connected to it there at the extension instead of the socket (since obviosly no space for the adapter) Would this even be remotly accurate? My thought is if the physical size of the torque adapter is to large for the location and you use an extension (reasonable size) to get you enough room for the adapter how much would this throw off the torque reading? Thanks again and i just aubscribed to your channel.

[@Dartmech]

You should have no problem with that setup. Any torque loss was negligible with extensions, so using one after a torque adapter shouldn’t hurt anything at all. 👍

[@stevensam8834]

What if you add the extension between the adaptor and the socket? Will that change the torque number accuracy? With smaller tight space in the engine bay, that adaptor won’t fit? Have you tested? Thanks in advance for your response. I’m on edge of buying one that’s why I’m asking.

[@laynevans75]

Would be interesting to know what torque was putting IN at the torque wrench itself. Like do you actually have to apply 55 to achieve 50 at the wheel nut.

[@Dartmech]

That's a great idea, But I think that depends on the torque wrench itself. That may be a future video to see which type of wrench is the most accurate.

[@brianhaygood183]

Torque in is torque out. If the extensions form a perfectly straight line and are all in line with the fastener, then the input equals the output torque. The only reason his readings vary at all is tiny misalignments of the wrench and fastener. This creates the same change in length issue a crowd foot does when not used at ninety degrees.

[@laynevans75]

@@brianhaygood183 Hmmm. Yeah I guess the input torque does have to equal the output torque. Maybe I'm thinking of the amount of travel that the input end has to go through to still create the same amount of torque.

[@ArdiArdi-cg5pr]

I have seen a few videos like this and Im sorry to say you are not good with the tools mate. You need to support the base of the wrench otherwise the power will get distributed in other directions instead of in torquing power. If you support properly the shaft you created you will get an accurate measurement. But for a mechanic this is an instinct to put one hand on the base of the wrench to keep it in centre and one in the the handle to produce leverage power.

[@RetiredSignDude]

Extensions would not be expected to increase torque. Suggest you swap out handle lengths!

[@Dartmech]

Oh just hand placement plays a part too.