TORQUE WRENCH FOR HIRE

Posted by: Onthlam on 10 October 2003

I have a wrench that will work on any of the Naim speakers that have 4mm alan screws.
I completed my torqueing about a month or so ago. Had very good results. I have passed it on to a fellow forum member who, I believe has also completed his mission..

If anyone would like to borrow it?
Please do not hesitate to ask.
It is set up for 3.6 and can be set up for a higher pressure if you so desire.Not necessary..

The only thing I ask is the last person to have it pays for the post to go to the next user.

Regards to all,

Marc

She asked for a Grand piano.
All I could give her was an upright organ...
Posted on: 16 October 2003 by syd
quote:
Originally posted by count.d:


What is the specific measured point? Tightening a bolt correctly is to a point where the bolt stretches to a within certain length range to clamp two surfaces without deforming the material.


That's correct. That's why the torque wrench or spanner as I call it was devised. This makes it easy to get a correct setting time after time. Incidentally I work in electronics and a couple of years ago an experiment at the then place I worked was conducted on how accurate assemblers were in gauging the feel of the correct settings. A 4 pound torque(just calibrated) was used and a number of workers were measured. It was surprising how much we were off the mark, mostly by overtightening. I thought it would be easy as I'm a bench hand fitter to trade ( Ifelt that I would have the Feel but my attempts ranged from 5 to 7 pounds over 6 attempts. Only one person got it right and that was only on one attempt. Incidentally a very expensive and accurate adjustable torque spanner was used to undo the screws. I was told that it cost over 500 dollars.

Yours in Music

Syd
Posted on: 17 October 2003 by Martin Payne
quote:
Originally posted by syd:
Incidentally a very expensive and accurate adjustable torque spanner was used to undo the screws. I was told that it cost over 500 dollars.



Syd,

what you have proved is that once the screws were done up, this was the force required to undo them again.

The friction between two objects depends on the speed that the objects are moving past each other. This is why people move heavy objects across the floor by giving them a shove "to get it going" - the friction is reduced while they are in motion.

When the screw is being done up, it is in motion, and thus the friction will be somewhat lower. You will turn the screw head until the combination of the force needed to stretch the screw thread (& compress the base material) and the touque needed to fight the friction of the screw material against the base material reaches the desired torque.

Once the screw is static, an additional force will be required to get it moving again, and this will be the value that is read by your torque wrench.

To prove that the experiment was accurate, you would need to do a screw up with the wrench set at four pounds, and then prove what force is required to undo that screw again. For all I know, this might be 4.1 pounds, or 6.1 pounds. I suspect it would vary wildly depending on the combination of materials in the screw and the base.

cheers,Martin

E-mail:- MartinPayne at Dial.Pipex.com
Posted on: 17 October 2003 by syd
Hi Martin

I'm not sure what your getting at here.Using a 4 pound torque to do up the screw I always found that the same torque driver was needed to undo it. Indeed we often found that components and subassemblies coming in from outside suppliers which should have been at 4 lbs or 8 lbs (the most commomn torque settings we used)often could'nt be undone with the correct driver and had to be undone by hand. It was not uncommon to sheer the head of a screw necessetating the return of component to the supplier to be repaired.

Yours in Music

Syd
Posted on: 17 October 2003 by Arthur Bye
The RS torque wrench that I have (picture is on another thread) seems quite sensitive to me. I've used it quite a few times and the "feel" of it tells me that it is working consistently. It adjusts in 1/10th of N/m and goes from 1 to 8 N/m

RS also sells an accessory to verify that your wrench is calibrated correctly.



Arthur Bye
Posted on: 17 October 2003 by Arthur Bye
quote:
Originally posted by Arthur Bye:
The RS torque wrench that I have (picture is on another thread) seems quite sensitive to me. I've used it quite a few times and the "feel" of it tells me that it is working consistently. It adjusts in 1/10th of N/m and goes from 1 to 8 N/m

RS also sells an accessory to verify that your wrench is calibrated correctly.

Seems to me that most dealers would have to have this wrench, otherwise the setup would be wrong. I would think most dealers would be willing to lend it out as needed.



Arthur Bye
RS torque wrench
Posted on: 18 October 2003 by Martin Payne
quote:
Originally posted by syd:
Using a 4 pound torque to do up the screw I always found that the same torque driver was needed to undo it.



Syd,

Your post didn't actually say that the torque required to undo a screw/nut was the same used to do it up in the first place.

Happy that you have clarified this.

cheers, Martin

E-mail:- MartinPayne at Dial.Pipex.com
Posted on: 18 October 2003 by syd
quote:
Originally posted by Martin Payne:
quote:
Originally posted by syd:
Using a 4 pound torque to do up the screw I always found that the same torque driver was needed to undo it.



Syd,

Your post didn't actually say that the torque required to undo a screw/nut was the same used to do it up in the first place.

Happy that you have clarified this.

cheers, Martin

E-mail:- MartinPayne at Dial.Pipex.com


OOPS I also did'nt state that in the experiment we were using ordinary hand screwdrivers to do up the screws then the adjustable torque driver at increasing settings to undo it. Strangely enough it was found that the girls on line tended to underestimate the force while the guys tended to overestimate the force needed. Haven't a clue why though.

Yours in Music

Syd
Posted on: 02 December 2003 by Martin Payne
quote:
Originally posted by Paul B:
Martin:

Could I get on the list after yourself. Let me know here and I'll email address.

Paul



Paul,

I understand that the device is in the post to me, so please let me have your contact details for me to forward it after I've used it.

Contact me using the details in my sig below.

cheers, Martin

E-mail:- MartinPayne (at) Dial.Pipex.com. Put "Naim" in the title.
Posted on: 03 December 2003 by Martin Payne
Status update - the wrench arrived here safely this morning.

I'll do my bolts over the weekend, and I can imagine we might do one or two other speakers at the same time, too.

cheers, Martin

E-mail:- MartinPayne (at) Dial.Pipex.com. Put "Naim" in the title.
Posted on: 03 December 2003 by Onthlam
Martin,
Ahh, dueling threads...
Please ask those who have theirs done to report back please....With type of speaker.....
If they so desire....

Have fun. I can not believe your going to wait.
If you not going to listen-fine..If you are? Big difference for sure........

Regards,

Marc