What keeps me awake at night! - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Garage - Tools
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 12-10-2012, 06:50 AM
Registered User
 
Join Date: Dec 2012
Location: New Marske. CLEVELAND. UK
Posts: 1
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
What keeps me awake at night!

Hi All

I am sat here bored and cant look at any of the websites I want to because the family are sat round me watching telly!!!!!!!!!

Anyhow I got to thinking about a longterm friendly argument that I have had with various friends and acquaintences over the years, and wondered if you might want to put youre take on the matter out there.

It came about when a friend had to make a one off spanner to fit on the end of his torque wrench in order to torque down his Harley Davidson cylinder base nuts.

He got a tape measure out and measured the total length of the torque wrench and added this to the length of the spanner and used the Torque=Force x Distance formula to figure out what to set the wrench at.
I argued that surely there must be a formula that DOESNT take into account the length of the torque wrench but instead uses the length of the additional spanner and the desired torque to be applied to the nuts. I gave the example that if the same spanner extension was used on different torque wrenches but to do the same job then surely all the torque wrenches would have to be set to the same poundage regardless of the torque wrench length. I further pointed out that as we know torque wrenches come in various lengths but it is accepted that providing the poundage scales overlap between wrenches then they will do the same job. There is the further factor that if the torque wrench is held ANYWHERE along its handle length, this will make no difference to the torque applied to the nut.

I have been on all sorts of websites and theire solution ALWAYS includes the length of the torque wrench in the equation.

I accept that the commonly spouted formula is the industry norm and it is used by people with far more wisdom and intelligence than me but I just think there has to be a mathematical solution that doesnt take into account ANYTHING regarding the torque wrench....other than the figure it is set to "Click" at, and I think the "NEW WONDER BILLY FORMULA" will express the percentage by which the torque wrench setting will have to be offset.

Unfortunately I am mathematically challenged and dont have the ability to prove my point on paper.
I have managed to get some people to see past the initial common formula and take up my point but eventually they come back to me and say there is no other way to do it, at this I say to the person that according to this formula, if the torque wrench were gripped in different points along its handle then each nut would be set to a different figure despite what the scale were set at (they then jump forward and say no that wouldnt be the case because the wrench would "Click" when the desired torque is being exerted on the nut (This is my whole point all along....torque wrenches deliver there desired output bang on the centreline/fulcrum point of there output (Usually 1/2" square drive) and so the length of the torque wrench is irrelevant in a formula to correct the setting in order to take into account the use of an adapting spanner or such like.

I would appreciate if you did take some time to see the angle I am coming from and try to help me get some sleep but would understand if you thought "Sod that he's thick" and just forgot about it all.
Take care

    Advertisement

Last edited by Guzziista; 12-10-2012 at 06:55 AM. Reason: Cut and paste went wrong
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 12-30-2012, 08:16 PM
Registered User
 
Join Date: Feb 2007
Location: Southeast Missouri
Posts: 121
Wiki Edits: 0

Thanks: 2
Thanked 0 Times in 0 Posts
That's kind of a hard question to follow, but I'll try. The Distance term in the Force x Distance equation is the distance between the nut and the location of the force being applied (eg. your hand).

You can't calculate torque applied without knowing the distance from the nut to the location of the force being applied.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 12-30-2012, 08:32 PM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 59
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 597 Times in 546 Posts
Couple thoughts:

An extension (like a crowsfoot), if used at a 90 degree angle to the torque wrench adds/subtracts nothing.

Using an extension straight out (or at anything other than a 90 degree angle) will need a correction factor. This is because the mechanical advantage is changed by adding length to the end of the wrench (where the torque is registered by the wrench.

A clicker torque wrench doesn't care where you grip it. That only changes the amount of input force required to get the same result at the other end.

A beam type wrench has to be gripped by the handle to register correctly because the shaft deflection is what's registering the torque.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 12-31-2012, 09:21 AM
Old Fool's Avatar
Registered User
 
Last photo:
Join Date: Jan 2008
Location: spokane,wa.
Posts: 1,347
Wiki Edits: 0

Thanks: 8
Thanked 40 Times in 34 Posts
I have thought about this same thing before.

The torque wrench is calibrated to display an applied force between the attachment point and a given point (beam type).

Add an additional length of leverage between the attachment point and the fastener and the displayed torque value is inaccurate as applied at the fastener.

The torque wrench is showing how much force is being applied at its end, not the end of the additional lever.

How to figure it out? I had an engineer tell me the math formula many years ago, but I remembered it for all of 2 milliseconds.

What I do remember is the displayed torque value was not the applied torque value at the fastener when additional lever was included.

One way to find out would be to take a torque wrench with an extension lever on it and directly couple it to a second torque wrench. mount one of the torque wrenches (t1)in a bench vise, apply a given torque to the other wrench (t2)and observe the value shown on t1 and compare to value on t2.

Now my head hurts
Reply With Quote Quick reply to this message

Recent Garage - Tools posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
What a night moontanker Off-Topic 0 11-11-2008 12:55 PM
Prom Night! OldSchoolChevy Off-Topic 11 04-24-2006 02:53 PM
My night Mightymouse Hotrodders' Lounge 54 08-23-2004 04:31 PM
This could be the night! meanroy Hotrodders' Lounge 7 06-16-2004 09:48 PM
what i did last night..... crazy larry Hotrodders' Lounge 3 09-15-2003 02:21 AM


All times are GMT -6. The time now is 04:22 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.