About Torque Sticks

[Chuck Newman]

I was browsing past threads I've missed and found "I am so hacked off!" from September '09.  What a great thread!  It was civil and  full of really useful information from differing points of view.

I have always torqued my lug nuts on all vehicles going back to the seventies.  I own several torque wrenches, the largest is 300 ft/lb.  I was going to purchase a 600 ft/lb wrench for my bus wheels and torque to 500 ft lbs, when I discovered (via some of you folks) the Torque Stick.  At TorqueStick.com they mention +/- 4% accuracy.  Is that a reliable figure?

If I get a 1" drive 475 ft/lb Torque Extension Bar (manufactured by AJ Manufacturing), do I still need to invest in a large torque wrench?

Thanks,

Chuck

[JackConrad]

Chuck,
    I can only speak of my personal experience. I have installed wheel nuts with a Harbor Freight 1" impact wrench using a torque stick and checked the torque setting with my 600 ft. lb. torque wrench. Numbers were very close. When using the torque stick I stop as soon as the socket stops turning (torque stick is twisting).  Jack

[kyle4501]

Ask them to send you a copy of the calibration instructions for the torque stick you are planning on buying.

If you 'calibrate' your impact wrench to the stick, then, yes, I believe their +/-4% accuracy claim. I'd venture they are probably more accurate over time than a 'clicker' torque wrench.

However, a torque stick is merely a tool. Used properly, it is a good tool that gives predictable results. Used improperly, the results are not as predictable.

[Ncbob]

I am considering selling my 600# torque wrench (Armstrong) so I'm not sure if I want to put it on the list of 'for sale items'.

I truly believe that having the tire guy just run 'em up easy and use my wrench is the best way to protect the Aluminum wheels.

It can be calibrated for about a $50 bill.

OK Nick, kick me into the other thread.

NCbob

[DaveG]

NC Bob, if you have the 600# wrench already, don't sell it.

The torque sticks work well, as stated.

There is a great place in the Midwest somewhere that calibrates torque wrenches for all the big names, guy there is real nice...don't remember the number or name, but PM me if you need it and I'll find it.

[tomhamrick]

Hey Kyle, Can you explain "calibrate the wrench to the Torque Stick"  ?  I have been wanting to get one of these for several years.
Thanks,   Tom Hamrick

[kyle4501]

One needs to understand how the impact wrench works & what the torque stick does before the calibration process makes sense.

Basically, a torque stick is a torsion spring. The more you twist it, the more toque it transmits.

An impact wrench has hammers that strike anvils to produce twist on the output shaft. This twist is only for a few degrees of rotation.

After the desired torque is reached, the energy of the hammers striking the anvils is absorbed in the twisting of the torque stick & not the fastener.


Torque stick sets are sized to apply a given torque based on a common fixed input torque.

If you have a set of torque sticks, AND you 'calibrate' your impact wrench, all you have to do to apply the correct torque is use the right stick.
They are most beneficial to shops that have several different torque requirements for the fasteners they are applying when time is limited.

The impact wrench is usually calibrated by:
- Tighten a nut to the torque that matches the torque stick.
- Use a quality regulator (that has repeatable settings) on the air supply to your impact wrench.
- Using the torque stick, increase air pressure to the impact wrench until the nut just moves.
- Back off the air pressure a little & tighten another nut.
- Check this nut with a torque wrench to verify actual torque.
- Fine tune air pressure as required to get the accuracy desired.
- Record air pressure & impact wrench setting.
- If you use these settings with the same impact wrench & torque stick set, you will enjoy the =/-4% accuracy.


Note-
Different impact wrenches may require different air pressure settings.
Different torque stick manufacturers may require different impact wrench settings.


If you apply too much input torque to a torque stick, you will over torque the fastener & may damage the torque stick.
(The tire shop did this to my 1988 420SEL & some of the wheel bolts had to be drilled out after the heads wrung off! I also enjoyed replacing the warped rims & hubs.  )
(Needless to say, I don't use them anymore.)


I hope all this makes sense.
It is for the above reasons, I chose to NOT spend my $$ on torque sticks. No real benefit in my garage.

For my needs, I can 'calibrate' my impact wrench to know the torque vs air pressure & not have to worry about over torqued fasteners. You still need to be carefull about letting it hammer after the nut stops turning.
AND, I still use a torque wrench when required. 
YMMV

[tomhamrick]

Thanks Kyle for that great explanation.
Tom Hamrick

[Chuck Newman]

Thank you all for the information and suggestions. 

Considering the importance of the subject, and the bus related money I've spent on less important items, I'm going to order a 600 lb torque wrench today.  And a torque stick.

Jack, like you I prefer to cross check things.  Makes for peace of mind. 

Thanks again,

Chuck

[gus]

Kyle,

That was a very clear and easily understandable explanation. I wish all of us could write this clearly!!

Now I know that, for me, it is far simpler and faster to use a torque wrench for final tightening after quick setting the nuts with my air wrench.

[kyle4501]

Thanks Gus, sometimes I get lucky. 
I wrote a bunch more than what I posted. It took a while to get it to sound right.


I don't want my friends thinking torque sticks are magical devices that are infallible. That is why I took the time to write that. My busnut friends are worth it. 

[bevans6]

It strikes me that no one has mentioned (or maybe I missed it) that torque sticks depend on the impact gun having greater torque capability than the torque stick, while being used.  The whole idea of calibrating the air pressure to your gun is to create a gun torque somewhat greater than required, so that the torsion spring action of the stick comes into play, absorbing the excess torque by twisting itself rather than turning the nut.

When the torque is too low - low air pressure, obstruction or kink in the hose you didn't notice, gun isn't lubed properly, it's below freezing and the moisture in the compressed air is freezing up the gun, or whatever - the gun spins the nut on and the nut stops turning, you let it hammer three times for good luck and you only have 200 odd foot pounds or whatever of torque and you can't really tell.  

Just a thought I had.  edit - the other thought I had was that impact guns often create different torque levels in reverse compared to forward, so think about that when you get set up to do the drivers side of your MCI.

Dropping a line to Santa about a torque wrench next week!

Brian

[JackConrad]

I don't want my friends thinking torque sticks are magical devices that are infallible. That is why I took the time to write that. My busnut friends are worth it. 

Exactly, that is why I double check each stud using my torque wrench.  Jack

[lostagain]

I put my 170lb body weight on the end of a 3 foot bar: that gives me +- 500 ft/lbs torque. Close enough for me.

JC

[JohnEd]

I recently had my rears R&R'd.  There used the "torque stick" to install the wheel.  The following day I put my Bud Wrench on a rear nut and it twisted easily off.  Maybe 50 pounds of force on a 2 foot bar.  NOT GOOD!  I am a friend of the owner and he has agreed to use a torque wrench on all of my rolling stock with no hard feelings on either side.

170 pounds on a three foot bar is a given torque and I think that is valid calibration.  Other than that I think the torque wrench is required.  The tire shops out here let the tech use whatever method he wants to tighten the lug nuts.  Then, the shop manager goes over every nut with a torque wrench....first loosening and then tightening so there are not even any nuts over tightened.  Careful, huh?  Thank TORT law according to the managers I talked to.

No stix.

John