Scotty, nothing I said to you is an argumentum ad hominem. Just a friendly primer in the behavior and tone we are used to here. I intended and intend no slur on your personal style. However, I generally find that a polite tone and trying to conform monkey see monkey do to the general culture you are entering for the first time is more effective in obtaining the results I want (information I don't have, gentle conversation, spirited debate, a soapbox for my humble opinions) than trying to impose myself inflexibly on that culture.

You seem quite intelligent. Probably well beyond the happy 140's, where you're smart enough to excell over your peers, but still dumb enough to be able to communicate and interact happily with them, without too great a degree of impatience. It's a tough learning curve to be part of the crowd if you fall above that relative intelligence benchmark. I take great interest in watching how guys like you do at that trick. Fail at it and it's like having way too much hp for your traction - you get nowhere.

Hang around for a while. It may get interesting. I find praticing anthropology to be one of my all time favorite pastimes...

BTW, while Harrier is dead right in the real world, I still think you haven't accounted for fastener diameter anywhere in there, but I buy the rest of Frank's stuff, and as Big Blue has stated before, You aren't going to get all that close with the best torque wrench YOU can afford anyway.

Scotty, forgot something. How are you going to adjust for the fact that every time you torque any one spoke, the previously applied torque of every other spoke you tightened will change? I'd get the hub centered with about 8 spokes tightened, using a dial indicator, then criss cross tightening pairs or quads (probably quads), then run the circle all the way around and adjust, then check hubcentricity again. Left out the dial gauge part on the "masters" anecdote above, sorry. They told me "round" is more important than tension, as there is a much smaller allowable variation in runout than there is in spoke tension.

Oh, and if you want to eliminate the correction for extension altogether, use two lateral extensions of equal length plus a long enough extension to clear the rim, and put the axis of the torque wrench square on the axis of the spoke - tack weld common spoke wrench in t/wrench axis hole of bottom lateral extension. Like the offset handle of the common brace and bit, if my explanation was unclear to you.

OK, Scotty... one last attempt.

Earlier today I spoke at some length with Mr. Roland LeClair, Chief Engineer at AKO, Inc., the company I referenced earlier that makes the "World's Finest" torque testing and measuring equipment. Mr. LeClair and I had a very nice discussion on the application of torque wrenches and why the length of the wrench should be taken into account. My summary of opinion was accepted by him as entirely accurate in principle and application.

Here's what I haven't explained (didn't want to try until I heard agreement from someone a lot smarter and more experienced with torque applications than me) and why the inclusion of the wrench length is necessary. A normal torque wrench used with no extension has a swing arc that is centered on the bolt. The wrench is calculated to reflect an accurate torque reading at a given handle length. When an extension enters the picture, the set torque delivered at the end of the wrench no longer has the center of the bolt as the point where force is applied. The force is now transferred to the extension, which has its own swing arc. Therefore the indicated force on the wrench is applied to the end of the extension and the calculation in effect must be re-figured to reflect accuracy. That's what the formula does for you through the relationship of the two lengths.

So, see, it's not "size", but "length" that matters after all. <img src="/forums/images/graemlins/lol.gif" alt="" />

As for "other than in-line" extensions, yes - length matters there as well - to a lesser degree as the extension rotates to perpendicular to the handle, where it then becomes "zero effect". I posted the formula for those variables as well.

Now I don't know what your game is, or why you insist on playing it - but if you're unwilling to accept the explanation, I suggest that you do as I did and call some of the manufacturers of torque wrenches and tell them your news flash that they've got it all wrong. I'll bet they would hire you on the spot as Chief Engineer if you can convince them why they're wrong and you're right. <img src="/forums/images/graemlins/shocked.gif" alt="" />

And while you're doing that, perhaps you could explain to us why you believe that handle length doesn't matter. You've tried to make a big noise that I haven't offered any facts or "enlightening thoughts".... exactly what facts have you submitted as proof of your formula - other than saying that you're right and everyone else is wrong? C'mon... some "enlightening thoughts" from your perspective, please.

FWIW, I did ask Mr. LeClair to take a look at your formula to see if there could be any measure of truth in it..... His answer?.......... "Ummmmmm, not quite".

Sorry, Scotty..... that dog just won't hunt. <img src="/forums/images/graemlins/shame.gif" alt="" />

I'm done......... poor horse. <img src="/forums/images/graemlins/rolleyes.gif" alt="" />

Frank

@Frank: Thanks for your diligence in referencing this. I understand more how the length of the handle can be a variable in certain applications.

Now take for instance the new hydraulic torque wrenches (click on sponser) or my half inch double handled torque drill and how does that formula work? It can't, because the torque is not specific to the handle length or direction the handles face. This is where scotty's formula comes in handy. I can also calculate the torque for the extension and double check everything using either beam or brake-away.


When using the extension, the direction you pull the handle in relation to the arc is very imprtant. I checked on a military site and they broke down the different angles of the extension to torque wrench and the handle length was important, however no mention was made as to bracing or following a particular arc from the bolt center, all of which are important.

The torque applied at the end of the extension should always be the same, and I mean the rotating force applied to the extension as if you were holding a double handled torque motor. Of course you would have to follow the swing of the extension with the center of the torque motor.

This has been very technical and the principles can cross over to other applications as in reinforcing or designing suspension etc. Even tightening bellhousing bolts using wobble soockets or universals change a torque settings.(check here) Fundamental understanding will help you find the solutions to many challenges. And yes, there has been some "off topic" banter, but it makes for an interesting read.

And one thing I'm not certain on still, is if 3 pounds at one foot is the same force as 1 lb at 3 ft. I'll trust it is for now, 'cuase if it ain't ....well that can be discussed later.

Thanks for all the participation, I must now get to work.

magoo -

The essence of torque multiplication is in the "ft/lbs" expression. 1 lb of force applied at 1' from the axis = 1 ft/lb of torque. 5 lbs of force applied at 12' = 60 ft/lbs of torque.

So, the answer to your question is - yes, they're the same torque value. And I don't think I want to discuss that any further, either. <img src="/forums/images/graemlins/lol.gif" alt="" />

Frank

I choose to remain ignorant to these arguments and obey what my torque wrench tells me. "Yes torque wrench - I will tighten to 21.5ft-lbs as you instruct me to" :zombie:

So a torque wrench is just another way of going wrong with confidence, right. That's comforting. I'll just go on using my calibrated arm that has been trained on gazillions of broken fasteners, except on head bolts, main bolts and rod bolts, where I'll use a torque wrench and go wrong with more confidence. It's like my Chevy that has a torque spec for an eccentric camber setting sleeve - That could be from Firesign Theatre - "Micky Way......."

I feel like Roberto Duran.....no mas,no mas! Seriously folks, my formula sucks and I apologize to all, especially
Frank.I don't have a full grasp of it yet but I'm wrong,wrong,wrong.Here's the example that set the stake in my heart.Two foot effective length torque wrench.Six inch extension.One hundred ft/lbs indicated on wrench scale.Now I know it takes a 50 lb pull to get that 100 lb indicated.I also know that my wrench and extension together act just like a solid bar,there's no magic happening at the juncture of the two.Therefore,a 50 lb pull on a 2.5 foot lever equals 125 ft/lbs of torque.Frank's formula predicts 125 ft/lbs. My POS predicts 150 ft/lbs.Somehow 50 lbs on a 2 foot lever does not equal 100 lbs. on a 1 foot lever.
I don't know,I understand some of it but not all of it....yet.The back and forth doesn't bother me,I enjoy setting people straight, it's the being wrong that cuts to the bone.Ya'll git a good laugh out of this but here goes anyway,it almost never ever happens.I've made my wife aware of all this and she is tickled to death, can't wait to tell this one on me to anybody that'll listen.Oh well it's nice to see her smile.Again, sorry fellas.

Scotty....I say it u can ('t always) believe it <img src="/forums/images/graemlins/shiner.gif" alt="" /> <img src="/forums/images/graemlins/cheers.gif" alt="" />

Scotty -

Welcome to the board.... your baptism is now complete and you're a full-fledged, dues-paying member in good standing! <img src="/forums/images/graemlins/kewl.gif" alt="" />

I'm certain we'll all benefit from your inquisitive mind and willingness to challenge the "norm" - qualities at the very foundation of improvement in all things mechanical. <img src="/forums/images/graemlins/cheers.gif" alt="" />

Frank

Thanks, now I'm right back where I started, No Formula <img src="/forums/images/graemlins/lol.gif" alt="" /> <img src="/forums/images/graemlins/lol.gif" alt="" />

Please, I would like a true formula for the torque excerted at the end of an extension to give the corrected torque value. AAARGH!

Let me clarify my confusion.

I need the axial force, rotational torque, parrallel to the bolt. I really don't care how long the wrench is or what type of torque wrench is used. The same force at the end of a 6" inch extension, in a radial, (torque) application is needed regardless of how applied, period.

Torque:
1. The moment of a force; the measure of a force's tendency to produce torsion and rotation about an axis, equal to the vector product of the radius vector from the axis of rotation to the point of application of the force and the force vector.
2. A turning or twisting force.

OK so maybe I don't know how torque is measured, but this is the deffinition, it's not about lever length. Those formula's presented on the web are just general formula's to get you in the ballpark. I want the real formula, maybe it has never be derived.

Lets take yet another example (hypothetical). I built a torque wrench specific for tightening lug nuts. I drilled the center of a torsion bar lengthwise and welded a indicator bar in the center. Now on the t-handle end I have a dial gauge to indicate the torque, with me? Now when I tighten my lug nuts with my t-wrench I can read the applied torque. This has been calibrated with many different weights through the full range so it is perfectly accurate. Weather I use a 1/2" socket or 1" socket the torque reads the same.

Now a couple of the lugnuts are behind a cap and I need a 4" extension to reach them, what is the formula to figure the torque correction. How long my handles on the t-bar doesn't matter, I can choke up on the handle or put a guy on both ends and the wrench reads applied torque. What would matter is to let the wrench float the arc swing.

This can't be that big of a deal. I just want to know the formula for the exension, not the 12 fingered monkey or any such after the fact calculations. EXAMPLE: 12 and 16 inch torque wrenches. 50lb of torque 6" extension = two separate settings for applied torque on the same exact 6" extension, this does not compute!!

The torque calculation would be for torque applied at a 6" arc, using centerlines of axis. So I guess the formula may not be as simple as the 1 lb at 3' = 3 lbs at 1' when it comes to torque. If it is that simple,(ratio) then my summation is correct: ratio of extension to torque value, but this may not be so when combining the effects of torque at the end of a lever (instead of dead weight) and this would be where all the discrepency comes from.

I guess when it comes to Mitsubishi's, we don't need to be so technical. I guess I'll just settle for status quo, a shame isn't it.

PS Scotty, you were doing such a good job fighting the good fight <img src="/forums/images/graemlins/coolg.gif" alt="" /> <img src="/forums/images/graemlins/coolg.gif" alt="" />

Sorry I missed this, I think the way you are using the extension needs clarification: no correction neccessary if your 3" extension is just the standard type extending the pivot length not arc you are fine, you probably wouldn't need a crowsfoot for a mitsubishi head bolt. So you're probably OK.