Shear nuts fitting by hand or impact gun?

[visor_down]

Hi all possibly a stupid Q.... but I can't find the answer so here goes.....is there any difference in the tightening torque achieved at the point of shear when shear nuts are fitted by hand vs impact gun?
My thought being does the impact gun cause it to shear at a lower torque than if applied by hand?

 

[m_c]

Your thought would be correct.
The shock loading from an impact gun will cause the nut to shear sooner, compared to the steady torque from being done by hand.

 

[Smallfry]

^^^^ What he said.

 

[DAPPH]

I turned my own sheer nuts out of some 10 mm stainless threaded long joining nuts to secure my stainless steel mailbox made by Paul of N Hants .
They went very very spanner tight before they sheered off ,

 

[Jack Ryan]

Fortunately, there is a tool - an impactless impact wrench.

DWT310 - Shear Wrench LXT®

Product

www.makitauk.com

Jack

 

[Agroshield]

Fortunately, there is a tool - an impactless impact wrench.

Different application I think. That is for use with torque shear (tension control) bolts used in structural steelwork (https://www.tcbolts.com/en/). With those, it is the splined tip that shears off.

I think the OP is thinking of security nuts, where the hex itself shears off, leaving an ungrippable smooth nut that is scrote-proof.

 

[MattF]

that is scrote-proof.

Does such a thing actually exist?

 

[Jack Ryan]

Different application I think. That is for use with torque shear (tension control) bolts used in structural steelwork (https://www.tcbolts.com/en/). With those, it is the splined tip that shears off.

I think the OP is thinking of security nuts, where the hex itself shears off, leaving an ungrippable smooth nut that is scrote-proof.

Sorry, I didn't look hard enough at the OP's application.

Jack

 

[Rrobson]

I would be very surprised if there’d be much in it tbh.
Doing them by hand ‘should’ ensure the tension applied to each one is in the ball park of design. An impact torque would be more sporadic and I recon you could get some tighter than by hand if you ran them in at speed.
Depends on the material of the bolt and what the application is. If they’re shear bolts on the space shuttle I’d be tempted to do them by hand. If they’re security shear bolts to anchor something to your garage floor I doubt it really matters.

 

[m_c]

The biggest issue with doing them with an impact gun, is if they go tight for some reason, they'll likely shear before you realise.
At least doing them by hand, you should realise they're not tightening as expected before they shear.

 

[Tigman]

Mind your knuckles , when they sheer off you go flying !

 

[colnerov]

I suppose it depends on the application. I was involved in converting LHD Minis from France to RHD when it was fashionable in the 80s. A lot of them didn't have the steering column shear bolts completely sheared off. We presumed it was part of the PDI to complete them and the French garages weren't doing it properly, it made our job easier.

 

[Morrisman]

Different application I think. That is for use with torque shear (tension control) bolts used in structural steelwork (https://www.tcbolts.com/en/). With those, it is the splined tip that shears off.

I think the OP is thinking of security nuts, where the hex itself shears off, leaving an ungrippable smooth nut that is scrote-proof.

I used a Sherpa van steering column on a hot rod project years ago. The shear nuts holding the steering lock in were intact. I just unscrewed them as normal, a touch puzzled at the odd design, a longish hex head with a deep V machined into it.

 

[DAPPH]

I used a Sherpa van steering column on a hot rod project years ago. The shear nuts holding the steering lock in were intact. I just unscrewed them as normal, a touch puzzled at the odd design, a longish hex head with a deep V machined into it.

6,000shear nuts not sheared would save 47 watts of power ?

 

[Robotstar5]

I used a Sherpa van steering column on a hot rod project years ago. The shear nuts holding the steering lock in were intact. I just unscrewed them as normal, a touch puzzled at the odd design, a longish hex head with a deep V machined into it.

As it was built by BL, the bloke who's job it was to shear them was probably off that day and union rules wouldn't allow anyone else to do the job