|
-
POSTING RULES

-
Donate yearly (please).
-
Advertise in here!
-
Today's Posts
|
Insert Pics
|

02-18-2012, 10:08 AM
|
 |
|
|
Join Date: Sep 2006
Location: Douglas Flat, CA
Posts: 589
|
|
Quote:
Originally Posted by WAM120RV
Bob
I totally agree about the potential dire consequences, and forgive my poor choice of words, should have said force.
I think the point I was trying to make is that there are a lot of opinions and calculations going on here which I suspect would cause more confusion. Also trying to put a light side on the thread.
Bottom line is if you search the web there is usually a calculator set up to do the mathematics for you.
|
Steve, my apologies for the brusque tone. The page you posted earlier, with the example and the calculator helps a lot to clarify what is going on here.
Thanks, Bob K.
__________________
Bob Kuykendall
HP-24 kit sailplane
EAA Technical Counselor
|

02-18-2012, 10:19 AM
|
|
|
|
Join Date: Dec 2006
Location: Coventry. England
Posts: 614
|
|
Here is another one
Bob
To be fair I was being a little naughty, in an attempt to lighten the tone. I was not actually expecting an answer, so no offense taken
Here is a better calculator which allows you to work out the torque setting when the crows foot is at different angles. The interesting point is that when it is at 90 degrees, you set the actual torque required on the nut.
http://www.cncexpo.com/TorqueAdapter.aspx
Perhaps I am getting lazy, although I could understand the maths if I dug into it, I don't need to.......... the web is fantastic!

__________________
http://www.aerobuilder.blogspot.com
Steve Arnold
England
In completion stage of Loehle P5151
Built and now Flying G.BVLR Vans RV4
Rebuilt G.BDBD Tailwind
Rebuilt G BVTN Kitfox
Built G CDCD RV9A with WAM120
Riveted wings on Glastar G.LEZZ Now (G. SKUA)
|

02-18-2012, 11:22 AM
|
|
|
|
Join Date: Mar 2007
Location: Livermore, CA
Posts: 167
|
|
Quote:
Originally Posted by WAM120RV
So, I have 2 foot long torque wrench but instead of pulling it at the handle, I decide to pull it in the middle 1 foot down its length.......will this alter the setting required.
|
Steve - Bob,
Please watch this video. It shows that for a clicker wrench you should not use it by grasping it in the middle. It will alter the setting required.
http://www.youtube.com/watch?v=_1LZk...Ru2bTi566Hn1Lf
__________________
Chris
RV-8 Wings
|

02-18-2012, 11:39 AM
|
 |
|
|
Join Date: Apr 2005
Location: KSLC
Posts: 4,021
|
|
Quote:
Originally Posted by CMW
|
After reviewing this video several times on a big screen, I can see that the movement of the arm, of "dial" torque wrench............is much more, when the click wrench is grasped at half it's length. It would seem, that this could effect the measurement we're looking for. Just an observation, as I have no facts.
|

02-18-2012, 11:42 AM
|
|
|
|
Join Date: Dec 2006
Location: Coventry. England
Posts: 614
|
|
Thanks
Chris
Thanks for posting this. In a previous life I served an engineering apprenticeship and would never hold the clicker or beam wrench in the middle. I hope what I said does not give anyone the idea that it OK to do this. As the video shows holding the wrench in the middle increases the force applied on the nut.
Your video should show the folly of this. Actually, we used to use a type of crows foot to tighten cylinder heads which put the drive directly over the bolt being tightened, so no correction factor was required for varying length torque wrenches.
All this discussion reminds me of a TV show many years ago called Tomorrows World. The topic was tightening nuts and bolts and the elastic limit of bolts. From memory ( which is getting a bit dodgy), the best way of ensuring the bolt was tightened to its maximum without exceeding the elastic limit was a very accurate measurement of the bolt length/stretch. The second best was a skilled craftsmans hands, and they showed that some people were almost as accurate by feel. The torque wrench came in third.
The tendency for the mere mortals is to over tighten, so a torque wrench is essential.
__________________
http://www.aerobuilder.blogspot.com
Steve Arnold
England
In completion stage of Loehle P5151
Built and now Flying G.BVLR Vans RV4
Rebuilt G.BDBD Tailwind
Rebuilt G BVTN Kitfox
Built G CDCD RV9A with WAM120
Riveted wings on Glastar G.LEZZ Now (G. SKUA)
Last edited by WAM120RV : 02-18-2012 at 11:47 AM.
Reason: More info
|

02-18-2012, 02:22 PM
|
 |
|
|
Join Date: Sep 2006
Location: Douglas Flat, CA
Posts: 589
|
|
Quote:
Originally Posted by CMW
|
Thanks, Chris. That is not the result I would have expected. It doesn't sway my conviction regarding the "0.8 correction factor," but it does seem to support the idea that you should only apply force at the handle of a torque wrench.
Thanks again, Bob K.
__________________
Bob Kuykendall
HP-24 kit sailplane
EAA Technical Counselor
|

02-18-2012, 02:38 PM
|
|
|
|
Join Date: Dec 2005
Posts: 155
|
|
Well
After research it seems all is not as simple as first thought. The common calculations using torque wrench arm length in calculations appear to be correct and my simple math and Allan's .8 conversion are incorrect.
There was the exact same scenario questioned on the physics forum. http://www.physicsforums.com/showthr...=432352&page=2
Allan's explanation/video should be very interesting.
George
|

02-18-2012, 02:44 PM
|
|
|
|
Join Date: Dec 2006
Location: Coventry. England
Posts: 614
|
|
Correction factor
George
Allan is correct that for a 1 foot torque wrench with a 3 inch crows foot the correction factor is .8 if held in line.
__________________
http://www.aerobuilder.blogspot.com
Steve Arnold
England
In completion stage of Loehle P5151
Built and now Flying G.BVLR Vans RV4
Rebuilt G.BDBD Tailwind
Rebuilt G BVTN Kitfox
Built G CDCD RV9A with WAM120
Riveted wings on Glastar G.LEZZ Now (G. SKUA)
|

02-18-2012, 02:59 PM
|
 |
|
|
Join Date: Sep 2006
Location: Douglas Flat, CA
Posts: 589
|
|
Quote:
Originally Posted by WAM120RV
George
Allan is correct that for a 1 foot torque wrench with a 3 inch crows foot the correction factor is .8 if held in line.
|
Yes, Allan is correct for that one specific case of the 12" torque wrench. He is incorrect for all other lengths. It similar to the broken clock being right twice a day.
Thanks, Bob K.
__________________
Bob Kuykendall
HP-24 kit sailplane
EAA Technical Counselor
|

02-18-2012, 05:32 PM
|
|
|
|
Join Date: Feb 2009
Location: Southbridge,MA
Posts: 193
|
|
Wow Allan, you couldn't have asked for any better advertising than this thread has created. 
__________________
Steve Stella
#40654 Finishing
N521RV reserved
|
| Thread Tools |
Search this Thread |
|
|
|
| Display Modes |
Linear Mode
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
All times are GMT -6. The time now is 02:16 AM.
|