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Torque Wrench Extension

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JSMcGrew(at)aol.com
Guest

Posted: Sat Apr 29, 2006 4:28 am Post subject: Torque Wrench Extension

I just came across a great idea that I want to share with the group. There  are a few times that a torque wrench won't fit on the nut/bolt (namely engine  mounting bolts, prop nuts, supporting the starter/alternator wires on the engine  case). Instead of purchasing expensive extensions or welding something up I  found that if you take an ordinary combination wrench and put a bolt/nut with  washers through the closed end you have a perfect extension. And you get to  keep your wrench intact. See photo below.

  

 You'll need to set your torque wrench to the appropriate setting when using  an extension. If you don't trust yourself with a calculator here's a website  that will do the math for you:

  

 http://www.norbar.com/torquewrenchextensioncalculator.php

  

 This is too easy, but I struggled with a few of these before I came across  this idea, so I figure it's worth sharing.

  

 Jim McGrew  

 #40134 - Fire  Wall Forward

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Tim(at)MyRV10.com
Guest

Posted: Sat Apr 29, 2006 4:57 am Post subject: Torque Wrench Extension

Jim, that is a genius idea!   I cobbled something together when

I did my prop bolts, and used an online torque calculator to

verify my own calculations on torque, but this wrench extension

is pure genius compared to what I did.  I'm going to put this

directly into the tips section on my site for permanent viewing

and for those who only get the daily digest.



http://www.myrv10.com/tips/generaltips.html

Tim Olson - RV-10 N104CD - Flying



JSMcGrew(at)aol.com wrote:

 	  Quote: 	
		   I just came across a great idea that I want to share with the group. 

 There are a few times that a torque wrench won't fit on the nut/bolt 

 (namely engine mounting bolts, prop nuts, supporting the 

 starter/alternator wires on the engine case). Instead of purchasing 

 expensive extensions or welding something up I found that if you take an 

 ordinary combination wrench and put a bolt/nut with washers through the 

 closed end you have a perfect extension. And you get to keep your wrench 

 intact. See photo below.

  

 You'll need to set your torque wrench to the appropriate setting when 

 using an extension. If you don't trust yourself with a calculator here's 

 a website that will do the math for you:

  

 http://www.norbar.com/torquewrenchextensioncalculator.php

  

 This is too easy, but I struggled with a few of these before I came 

 across this idea, so I figure it's worth sharing.

  

 Jim McGrew

 #40134 - Fire Wall Forward

jesse(at)itecusa.org
Guest

Posted: Sat Apr 29, 2006 5:39 am Post subject: Torque Wrench Extension

That’s a great idea.    

   

I have one issue with this website.  It has you input the length of your existing torque wrench, then the length with the extension.  I understand wanting to know the length from the center of the drive to the break-away point, but what in the world difference can the length of the handle mean?  Does it really make a different torque value if you grab the handle at the end or “choke up” to the head?  Am I really missing something huge here?  

   

Also, I heard from an A&P school that if you put the extension at 90 degrees, then the torque value on the wrench is accurate, but then, of course, you can’t use the racheting feature of the torque wrench, or you will lose your 90 degrees.  

   

Do not archive.  

     

Jesse Saint  

I-TEC, Inc.  

jesse(at)itecusa.org (jesse(at)itecusa.org)  

www.itecusa.org  

352-465-4545  

        

  

From: owner-rv10-list-server(at)matronics.com [mailto:owner-rv10-list-server(at)matronics.com] On Behalf Of JSMcGrew(at)aol.com

 Sent: Saturday, April 29, 2006 7:27 AM

 To: rv10-list(at)matronics.com

 Subject: Torque Wrench Extension  

  

     

I just came across a great idea that I want to share with the group. There are a few times that a torque wrench won't fit on the nut/bolt (namely engine mounting bolts, prop nuts, supporting the starter/alternator wires on the engine case). Instead of purchasing expensive extensions or welding something up I found that if you take an ordinary combination wrench and put a bolt/nut with washers through the closed end you have a perfect extension. And you get to keep your wrench intact. See photo below.  

    

   

    

You'll need to set your torque wrench to the appropriate setting when using an extension. If you don't trust yourself with a calculator here's a website that will do the math for you:  

    

   

    

http://www.norbar.com/torquewrenchextensioncalculator.php  

    

   

    

This is too easy, but I struggled with a few of these before I came across this idea, so I figure it's worth sharing.  

    

   

    

Jim McGrew   

    

#40134 - Fire Wall Forward  

    

   

    

[img]cid:image001.jpg(at)01C66B67.E302E8A0[/img]

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Kellym

Joined: 10 Jan 2006
Posts: 1706
Location: Sun Lakes AZ

Posted: Sat Apr 29, 2006 6:35 am Post subject: Torque Wrench Extension

While it is an inventive way to do it, I wonder about the impact of the 

angle on the wrench shown, and might point out that a set of crow's foot 

wrenches from Sears isn't all that much money. The crow's foot works 

fine on Hartzel props.



Tim Olson wrote:

 	  Quote: 	
		   



 Jim, that is a genius idea!   I cobbled something together when

 I did my prop bolts, and used an online torque calculator to

 verify my own calculations on torque, but this wrench extension

 is pure genius compared to what I did.  I'm going to put this

 directly into the tips section on my site for permanent viewing

 and for those who only get the daily digest.



 http://www.myrv10.com/tips/generaltips.html

 Tim Olson - RV-10 N104CD - Flying

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

JSMcGrew(at)aol.com
Guest

Posted: Sat Apr 29, 2006 6:38 am Post subject: Torque Wrench Extension

Jesse,

  

 This falls in the category of waxing philosophical on a subject and that  doesn't help get my plane in the air any faster BUT I'm totally with you. I  struggled with that as well so here goes.

  

 If you are working with a beam type torque wrench you must hold it on the  handle and center the handle on its pivot in order to get an accurate  reading, in this case it is easy to understand why the calculation needs  the torque wrench length. With the micrometer or "click" type torque  wrenches you don't necessarily have to hold it by the handle to get an  accurate torque because the spring is set to the value you want - that  is, unless you are using an extension.

  

 Hang with me and please excuse the math, this is how I understand it.  Consider the following 2 cases:

  

 You are using a 20 inch long micrometer type torque wrench set at 100  in-lbs attached to a 10 inch extension.

  

 1) If you hold the torque wrench by the handle you must apply 5 lbs of  force to create 100 in-lbs of moment (torque) at the head and cause it to click  (5 lbs x 20"). At the end of your 10" extension you are creating 150  in-lbs of torque (5 lbs x 30 inches).

  

 2) If you "choke" up on the torque wrench and hold it, say, 10" from the  head you must apply 10 lbs of force in order to get it to click at 100 in-lbs.  Now at the end of your 10" extension you are applying 200 in-lbs of torque (10  lbs x 20 inches)

  

 As far as using the extension other than straight - I'm not an A&P, but  I am an engineer and the math tells me that bending the torque wrench does make  a difference. Your moment arm now becomes the hypotenuse of the triangle created  by the torque wrench and extension. The further you bend the extension the  shorter your moment arm becomes and, thus, the less torque you have at the end  of your extension. This is a minor correction until the angle starts getting  beyond about 45 degrees. I will skip the geometry involved. Consider the case if  you bent the extension all the way back toward you, aligned with the torque  wrench... now the moment arm is equal to the length of the torque wrench MINUS  the length of the extension.

  

 Sorry for the dissertation. I had to prove this to myself before I torqued  my prop bolts.

  

 The bottom line: The website calculation works for a straight  extension.

  

 Jim 

 40134

  

 In a message dated 4/29/2006 7:43:37 A.M. Mountain Daylight Time,  jesse(at)itecusa.org writes:

  	  Quote: 	
		        

Thatâ€™s a great    idea.     

    

I have one issue with    this website.  It has you input the length of your existing torque    wrench, then the length with the extension.  I understand wanting to know    the length from the center of the drive to the break-away point, but what in    the world difference can the length of the handle mean?  Does it really    make a different torque value if you grab the handle at the end or â€œchoke upâ€    to the head?  Am I really missing something huge    here?   

    

Also, I heard from an    A&P school that if you put the extension at 90 degrees, then the torque    value on the wrench is accurate, but then, of course, you canâ€™t use the    racheting feature of the torque wrench, or you will lose your 90    degrees.   

    

Do not    archive.   

       

Jesse    Saint   

I-TEC,    Inc.   

jesse(at)itecusa.org (jesse(at)itecusa.org)   

www.itecusa.org   

352-465-4545

            

   

From:    owner-rv10-list-server(at)matronics.com    [mailto:owner-rv10-list-server(at)matronics.com] On Behalf Of JSMcGrew(at)aol.com

Sent: Saturday, April 29, 2006 7:27    AM

To:    rv10-list(at)matronics.com

Subject: Torque Wrench    Extension

   

       

I just came across a    great idea that I want to share with the group. There are a few times that a    torque wrench won't fit on the nut/bolt (namely engine mounting bolts, prop    nuts, supporting the starter/alternator wires on the engine case). Instead of    purchasing expensive extensions or welding something up I found that if    you take an ordinary combination wrench and put a bolt/nut with    washers through the closed end you have a perfect extension. And you get    to keep your wrench intact. See photo  below.

      

 

      

You'll need to set    your torque wrench to the appropriate setting when using an extension. If you    don't trust yourself with a calculator here's a website that will do the math    for you:

      

 

      

http://www.norbar.com/torquewrenchextensioncalculator.php

      

 

      

This is too easy,    but I struggled with a few of these before I came across this idea, so I    figure it's worth sharing.

      

 

      

Jim McGrew    

      

#40134 - Fire Wall    Forward

      

 

      



   

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 Jim "Scooter"  McGrew

jsmcgrew(at)aol.com

JSMcGrew(at)aol.com
Guest

Posted: Sat Apr 29, 2006 6:45 am Post subject: Torque Wrench Extension

I had a few places where the crow's feet didn't work for me. I won't get  into details... in my opinion the angle of the wrench doesn't make an  appreciable difference.

  

 Jim

  

 In a message dated 4/29/2006 8:36:26 A.M. Mountain Daylight Time,  kellym(at)aviating.com writes:

  	  Quote: 	
		  -->    RV10-List message posted by: Kelly McMullen    <kellym(at)aviating.com>



While it is an inventive way to do it, I    wonder about the impact of the 

angle on the wrench shown, and might point    out that a set of crow's foot 

wrenches from Sears isn't all that much    money. The crow's foot works 

fine on Hartzel props.



Tim Olson    wrote:

 	  Quote: 	
		   --> RV10-List message posted by: Tim Olson    <Tim(at)MyRV10.com>



 Jim, that is a genius idea!      I cobbled something together when

 I did my prop bolts, and used an    online torque calculator to

 verify my own calculations on torque, but    this wrench extension

 is pure genius compared to what I did.  I'm    going to put this

 directly into the tips section on my site for    permanent viewing

 and for those who only get the daily    digest.



    http://www.myrv10.com/tips/generaltips.html

 Tim Olson    - RV-10 N104CD -  ==========================     es  Day                                                     

  -->  ==================================================              - NEW MATRONICS LIST WIKI -
	


_-=  sp;                           ->  =========================p;               - List Contribution Web Site                               ==================================================



	


 



  

 Jim "Scooter"  McGrew

jsmcgrew(at)aol.com

flysrv10(at)gmail.com
Guest

Posted: Sat Apr 29, 2006 6:56 am Post subject: Torque Wrench Extension

Great Idea!  I used a expensive Crows Foot but had to go and shop for

it.  This would have done just fine.



do not archive.



On 4/29/06, JSMcGrew(at)aol.com <JSMcGrew(at)aol.com> wrote:

 	  Quote: 	
		  

 I just came across a great idea that I want to share with the group. There

 are a few times that a torque wrench won't fit on the nut/bolt (namely

 engine mounting bolts, prop nuts, supporting the starter/alternator wires on

 the engine case). Instead of purchasing expensive extensions or welding

 something up I found that if you take an ordinary combination wrench and put

 a bolt/nut with washers through the closed end you have a perfect extension.

 And you get to keep your wrench intact. See photo below.



 You'll need to set your torque wrench to the appropriate setting when using

 an extension. If you don't trust yourself with a calculator here's a website

 that will do the math for you:



 http://www.norbar.com/torquewrenchextensioncalculator.php



 This is too easy, but I struggled with a few of these before I came across

 this idea, so I figure it's worth sharing.



 Jim McGrew

 #40134 - Fire Wall Forward

Tim(at)MyRV10.com
Guest

Posted: Sat Apr 29, 2006 7:18 am Post subject: Torque Wrench Extension

A note about the crow's foot.  I think I used one on my prop bolts,

but it was hard to get something that stuck out far enough away

from the prop hub to allow the wrench to fit in good too.

Ideally, you'd use an extended crows foot type arrangement, which

is a tool Hartzell sells.  But, what he did with the bolt

and open end wrench essentially duplicates the extended crows foot,

and from what I can tell, I think that's probably the simplest

way to get those prop bolts tightened.



Tim Olson - RV-10 N104CD - Flying

do not archive

Rob Kermanj wrote:

 	  Quote: 	
		   

 

 Great Idea!  I used a expensive Crows Foot but had to go and shop for

 it.  This would have done just fine.

 

 do not archive.

 

 On 4/29/06, JSMcGrew(at)aol.com <JSMcGrew(at)aol.com> wrote:

>

> I just came across a great idea that I want to share with the group. 

> There

> are a few times that a torque wrench won't fit on the nut/bolt (namely

> engine mounting bolts, prop nuts, supporting the starter/alternator 

> wires on

> the engine case). Instead of purchasing expensive extensions or welding

> something up I found that if you take an ordinary combination wrench 

> and put

> a bolt/nut with washers through the closed end you have a perfect 

> extension.

> And you get to keep your wrench intact. See photo below.

>

> You'll need to set your torque wrench to the appropriate setting when 

> using

> an extension. If you don't trust yourself with a calculator here's a 

> website

> that will do the math for you:

>

> http://www.norbar.com/torquewrenchextensioncalculator.php

>

> This is too easy, but I struggled with a few of these before I came 

> across

> this idea, so I figure it's worth sharing.

>

> Jim McGrew

> #40134 - Fire Wall Forward

>

 

 

 

 

 http://www.matronics.com/Navigator?RV10-List

 http://wiki.matronics.com

jesse(at)itecusa.org
Guest

Posted: Sat Apr 29, 2006 4:31 pm Post subject: Torque Wrench Extension

Not to argue with you (do not archive – ok, that’s out of the way), but isn’t the thing that matters how much torque there is at the head to make it click, not how much force you are putting on it.  If it is the same torque wrench set at the same setting with the same extension, shouldn’t it give the exact same amount of torque no matter where on the wrench you grab it?  It will require more force from the person, but the leverage from the hand to the click should be isolated form the amount of torque from the click to the nut, right?  Well, maybe that’s why I am an accountant and not an engineer.  

     

Jesse Saint  

I-TEC, Inc.  

jesse(at)itecusa.org (jesse(at)itecusa.org)  

www.itecusa.org  

352-465-4545  

        

  

From: owner-rv10-list-server(at)matronics.com [mailto:owner-rv10-list-server(at)matronics.com] On Behalf Of JSMcGrew(at)aol.com

 Sent: Saturday, April 29, 2006 9:38 AM

 To: rv10-list(at)matronics.com

 Subject: Re: Torque Wrench Extension  

  

         

Jesse,  

    

   

    

This falls in the category of waxing philosophical on a subject and that doesn't help get my plane in the air any faster BUT I'm totally with you. I struggled with that as well so here goes.  

    

   

    

If you are working with a beam type torque wrench you must hold it on the handle and center the handle on its pivot in order to get an accurate reading, in this case it is easy to understand why the calculation needs the torque wrench length. With the micrometer or "click" type torque wrenches you don't necessarily have to hold it by the handle to get an accurate torque because the spring is set to the value you want - that is, unless you are using an extension.  

    

   

    

Hang with me and please excuse the math, this is how I understand it. Consider the following 2 cases:  

    

   

    

You are using a 20 inch long micrometer type torque wrench set at 100 in-lbs attached to a 10 inch extension.  

    

   

    

1) If you hold the torque wrench by the handle you must apply 5 lbs of force to create 100 in-lbs of moment (torque) at the head and cause it to click (5 lbs x 20"). At the end of your 10" extension you are creating 150 in-lbs of torque (5 lbs x 30 inches).  

    

   

    

2) If you "choke" up on the torque wrench and hold it, say, 10" from the head you must apply 10 lbs of force in order to get it to click at 100 in-lbs. Now at the end of your 10" extension you are applying 200 in-lbs of torque (10 lbs x 20 inches)  

    

   

    

As far as using the extension other than straight - I'm not an A&P, but I am an engineer and the math tells me that bending the torque wrench does make a difference. Your moment arm now becomes the hypotenuse of the triangle created by the torque wrench and extension. The further you bend the extension the shorter your moment arm becomes and, thus, the less torque you have at the end of your extension. This is a minor correction until the angle starts getting beyond about 45 degrees. I will skip the geometry involved. Consider the case if you bent the extension all the way back toward you, aligned with the torque wrench... now the moment arm is equal to the length of the torque wrench MINUS the length of the extension.  

    

   

    

Sorry for the dissertation. I had to prove this to myself before I torqued my prop bolts.  

    

   

    

The bottom line: The website calculation works for a straight extension.  

    

   

    

Jim   

    

40134  

    

   

    

In a message dated 4/29/2006 7:43:37 A.M. Mountain Daylight Time, jesse(at)itecusa.org writes:  

   	  Quote: 	
		      

That’s a great idea.    

   

I have one issue with this website.  It has you input the length of your existing torque wrench, then the length with the extension.  I understand wanting to know the length from the center of the drive to the break-away point, but what in the world difference can the length of the handle mean?  Does it really make a different torque value if you grab the handle at the end or “choke up” to the head?  Am I really missing something huge here?  

   

Also, I heard from an A&P school that if you put the extension at 90 degrees, then the torque value on the wrench is accurate, but then, of course, you can’t use the racheting feature of the torque wrench, or you will lose your 90 degrees.  

   

Do not archive.  

     

Jesse Saint  

I-TEC, Inc.  

jesse(at)itecusa.org (jesse(at)itecusa.org)  

www.itecusa.org  

352-465-4545  

        

  

From: owner-rv10-list-server(at)matronics.com [mailto:owner-rv10-list-server(at)matronics.com] On Behalf Of JSMcGrew(at)aol.com

 Sent: Saturday, April 29, 2006 7:27 AM

 To: rv10-list(at)matronics.com

 Subject: Torque Wrench Extension  

  

     

I just came across a great idea that I want to share with the group. There are a few times that a torque wrench won't fit on the nut/bolt (namely engine mounting bolts, prop nuts, supporting the starter/alternator wires on the engine case). Instead of purchasing expensive extensions or welding something up I found that if you take an ordinary combination wrench and put a bolt/nut with washers through the closed end you have a perfect extension. And you get to keep your wrench intact. See photo below.  

    

   

    

You'll need to set your torque wrench to the appropriate setting when using an extension. If you don't trust yourself with a calculator here's a website that will do the math for you:  

    

   

    

http://www.norbar.com/torquewrenchextensioncalculator.php  

    

   

    

This is too easy, but I struggled with a few of these before I came across this idea, so I figure it's worth sharing.  

    

   

    

Jim McGrew   

    

#40134 - Fire Wall Forward  

    

   

    

   

  

  

   

--

 No virus found in this incoming message.

 Checked by AVG Free Edition.

 Version: 7.1.385 / Virus Database: 268.5.1/327 - Release Date: 4/28/2006  

   

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 No virus found in this outgoing message.

 Checked by AVG Free Edition.

 Version: 7.1.385 / Virus Database: 268.5.1/327 - Release Date: 4/28/2006  	
  

  

    

   

    

Jim "Scooter" McGrew

 jsmcgrew(at)aol.com

pitts_pilot(at)bellsouth.
Guest

Posted: Sat Apr 29, 2006 5:56 pm Post subject: Torque Wrench Extension

Jesse Saint wrote:

  	  Quote: 	
		                   v\:* {behavior:url(#default#VML);} o\:* {behavior:url(#default#VML);} w\:* {behavior:url(#default#VML);} .shape {behavior:url(#default#VML);}  <![endif]-->                    

Not to argue with you (do not archive – ok, that’s out of the way), but isn’t the thing that matters how much torque there is at the head to make it click, not how much force you are putting on it.  If it is the same torque wrench set at the same setting with the same extension, shouldn’t it give the exact same amount of torque no matter where on the wrench you grab it?  It will require more force from the person, but the leverage from the hand to the click should be isolated form the amount of torque from the click to the nut, right?  Well, maybe that’s why I am an accountant and not an engineer.      

            

Jesse Saint      

I-TEC, Inc.      

jesse(at)itecusa.org (jesse(at)itecusa.org)      

www.itecusa.org      

352-465-4545   

   

 	
 Jesse, nobody argues on this list    .... they just discusses things to death!    You're 1/2 right in your statement.

 Torque is measured in foot-pounds.  Foot being the distance from the 'head' to where the force is applied, which is in pounds.  If the torque wrench is 2 feet long, and you press with 2 pounds at the end of the torque wrench, you have 4 foot-pounds of torque.  Now, if you grasp the torque wrench in the middle and apply the same pressure, that's only 2 foot-pounds.  It's a leverage thingy.  You hit it right when you said "It will require more force from the person" ..... and to give the bolt (or nut) the same torque you'd have to push 4 pounds.

 

 Some folks get downright anal about it when you put a crows-foot on the end of the torque wrench, which adds (maybe) 1/2" to the length and HAVE to calculate the new foot-pounds!!!  Sheesh.  Well, grab your geometry book off the shelf if you put the crows foot 90 degrees from the side!!!   

 

 Well, as you can probably tell, I don't figure ..... I just do it.  And I haven't had any failures (yet) from winging (highly technical term) it.

 Linn

john(at)ballofshame.com
Guest

Posted: Sat Apr 29, 2006 6:43 pm Post subject: Torque Wrench Extension

You almost have to think about it as a bending moment thing.  Here's 

an argument that should convince you, though:



If it's true that it doesn't matter where on the handle you're pushing, 

then as I reduce the length of the handle on the torque wrench it will 

always break at the same point given X torque on the screw, right?



Now imagine that the handle gets shorter and shorter and shorter.  You 

can imagine that at some point the handle gets so short (say .01" long) 

that it would require an ENOURMOUS torque to get that torque wrench 

to break (given that you left the torque setting constant).  At the limiting 

case, the length of the handle is 0 and it will require infinite torque to 

get the wrench to break.



In the case of no extension, it doesn't matter where you hold the 

handle because the ratio of handle to extension is always the same ( = 

0 ) and that's really what determines what your torque setting must be.  

This isn't true for a beam style wrench.  Once again, a beam style is a 

bending moment thingy and you have to hold it in the right place.  

Think of the beam style as zillions of little torque wrenches all hooked 

up head to tail 



I hope this helps and doesn't just confuse the issue more.  Also, I've 

been deburring ribs all day so take it with a grain of salt...it looks right 

from here, though...



-John Coloccia

On 29 Apr 2006 at 19:30, Jesse Saint wrote:



 	  Quote: 	
		   

 Not to argue with you (do not archive “ok, that™s out of the way), but isn™t the thing that matters 

 how much torque there is at the head to make it click, not how much force you are putting on it. If 

 it is the same torque wrench set at the same setting with the same extension, shouldn™t it give the 

 exact same amount of torque no matter where on the wrench you grab it? It will require more 

 force from the person, but the leverage from the hand to the click should be isolated form the 

 amount of torque from the click to the nut, right? Well, maybe that™s why I am an accountant and 

 not an engineer.

 

 Jesse Saint

 I-TEC, Inc.

 jesse(at)itecusa.org

 www.itecusa.org

 352-465-4545

 

 

 

 From: owner-rv10-list-server(at)matronics.com [mailto:owner-rv10-list-server(at)matronics.com] On 

 Behalf Of JSMcGrew(at)aol.com

 Sent: Saturday, April 29, 2006 9:38 AM

 To: rv10-list(at)matronics.com

 Subject: Re: Torque Wrench Extension

 

 

 Jesse,

 

 

 

 This falls in the category of waxing philosophical on a subject and that doesn't help get my plane 

 in the air any faster BUT I'm totally with you. I struggled with that as well so here goes.

 

 

 

 If you are working with a beam type torque wrench you must hold it on the handle and center the 

 handle on its pivotin order to get an accurate reading, in this case it is easy to understand whythe 

 calculation needs thetorque wrench length.With the micrometer or "click" type torque wrenches 

 you don't necessarily have to hold it by the handle to get an accuratetorque because the spring is 

 set to the value you want- that is, unless you are using an extension.

 

 

 

 Hang with me and please excuse the math, this is how I understand it. Consider the following 2 

 cases:

 

 

 

 You are using a 20 inch long micrometer type torque wrench set at 100 in-lbs attached to a 10 

 inch extension.

 

 

 

 1) If you hold the torque wrench by the handle you must apply 5 lbs of force to create 100 in-lbs of 

 moment (torque) at the head and cause it to click (5 lbs x 20"). At the end of your10"extension 

 you are creating 150 in-lbs of torque (5 lbs x 30 inches).

 

 

 

 2) If you "choke" up on the torque wrench and hold it, say, 10" from the head you must apply 10 

 lbs of force in order to get it to click at 100 in-lbs. Now at the end of your 10" extension you are 

 applying 200 in-lbs of torque (10 lbs x 20 inches)

 

 

 

 As far as using the extension other than straight - I'm not an A&P, but I am an engineer and the 

 math tells me that bending the torque wrench does make a difference. Your moment arm now 

 becomes the hypotenuse of the triangle created by the torque wrench and extension. The further 

 you bend the extension the shorter your moment arm becomes and, thus, the less torque you 

 have at the end of your extension. This is a minor correction until the angle starts getting beyond 

 about 45 degrees. I will skip the geometry involved. Consider the case if you bent the extension all 

 the way back toward you, aligned with the torque wrench... now the moment arm is equal to the 

 length of the torque wrench MINUS the length of the extension.

 

 

 

 Sorry for the dissertation. I had to prove this to myself before I torqued my prop bolts.

 

 

 

 The bottom line: The website calculation works for a straight extension.

 

 

 

 Jim 

 

 40134

 

 

 

 In a message dated 4/29/2006 7:43:37 A.M. Mountain Daylight Time, jesse(at)itecusa.org writes:

 

     That™s a great idea. 

 

 I have one issue with this website. It has you input the length of your existing torque wrench, then 

 the length with the extension. I understand wanting to know the length from the center of the drive 

 to the break-away point, but what in the world difference can the length of the handle mean? 

 Does it really make a different torque value if you grab the handle at the end or œchoke up to the 

 head? Am I really missing something huge here?

 

 Also, I heard from an A&P school that if you put the extension at 90 degrees, then the torque 

 value on the wrench is accurate, but then, of course, you can™t use the racheting feature of the 

 torque wrench, or you will lose your 90 degrees.

 

 Do not archive.

 

 Jesse Saint

 I-TEC, Inc.

 jesse(at)itecusa.org

 www.itecusa.org

 352-465-4545

 

 

 

 From: owner-rv10-list-server(at)matronics.com [mailto:owner-rv10-list-server(at)matronics.com] On 

 Behalf Of JSMcGrew(at)aol.com

 Sent: Saturday, April 29, 2006 7:27 AM

 To: rv10-list(at)matronics.com

 Subject: Torque Wrench Extension

 

 

 I just came across a great idea that I want to share with the group. There are a few times that a 

 torque wrench won't fit on the nut/bolt (namely engine mounting bolts, prop nuts, supporting the 

 starter/alternator wires on the engine case). Instead of purchasing expensive extensions or 

 welding something upI found that if you take an ordinary combination wrench and put a bolt/nut 

 with washersthrough the closed end you have a perfect extension. And you get to keep your 

 wrench intact. See photo below.

 

 

 

 You'll need to set your torque wrench to the appropriate setting when using an extension. If you 

 don't trust yourself with a calculator here's a website that will do the math for you:

 

 

 

 http://www.norbar.com/torquewrenchextensioncalculator.php

 

 

 

 This is too easy, but I struggled with a few of these before I came across this idea, so I figure it's 

 worth sharing.

 

 

 

 Jim McGrew 

 

 #40134 - Fire Wall Forward

 

 

 

 

 

 

 

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 Checked by AVG Free Edition.

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 No virus found in this outgoing message.

 Checked by AVG Free Edition.

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 Jim "Scooter" McGrew

 jsmcgrew(at)aol.com

 

 

 

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