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-   -   NEW! Ultimate C/S Prop Wrench Anti Splat Aero (https://vansairforce.net/community/showthread.php?t=82592)

JonJay 02-15-2012 09:40 AM

Here is a question. Is it possible that the tried and true formula applies only to old school, beam type, wrenches?
The beam type handle has a pivot to insure that you are applying the pressure at one specific point on the handle. The "click" type do not. I assume you can apply pressure anywhere on the handle and it will click at the correct torque regardless. That is an assumption, but if it is true, the length of your click type wrench would not matter and the .8 multiplier would work on any of them since they are all calibrated at the head for foot pounds.

Radomir 02-15-2012 09:44 AM

Jon.. no.. Go back and read post #64 by Marc Hudson... then re-read it 10 more times until you understand the importance of point "B" on the drawing.

JonJay 02-15-2012 09:45 AM

Quote:

Originally Posted by Radomir (Post 629411)
Jon.. no.. Go back and read post #64 by Marc Hudson... then re-read it 10 more times until you understand the importance of point "B" on the drawing.

You know a thread is going on too long when I have to go back from #122 to #64. Sorry, I will go read that one.

erich weaver 02-15-2012 09:47 AM

Quote:

Originally Posted by Brantel (Post 629348)
The formulas that all of you are getting stuck on are only for simple levers and pivots.

I follow the thought process that argues for a constant 0.8 multiplier when using a ft lbs torque wrench, but this quote just isnt true according to the documentation that has been presented in this thread. The formulas in the Service Bulletin, the Hartzell manual and the AC are all essentially the same and specifically indicate to input the length of the TORQUE WRENCH into the equation. They do not qualify the formula as applying only to simple levers without torque settings, and they most certainly DO NOT say to just enter 1 ft into the formula if your torque wrench reads in ft lbs.

If the "0.8 is a constant" folks are somehow correct here, it is disturbing to think that so many people have misinterpreted or been deceived by all the published documentation to date for so long. Makes me think that perhaps the documents have it right after all.

erich

Radomir 02-15-2012 09:49 AM

True dat!! The thread would have been a lot shorter if everyone just went and read manual for their torque wrench :) and from what I gather they all read the same.. PS.. there are several other good explanations on this thread by several other folks... maybe diferent styles would help.

Either way, you actually don't need to "understand" any of this.. just follow instructions from the manual, or 43.13, or any other publication.. they all show the same formula... there really should be no 100+ posts about this :)

JonJay 02-15-2012 09:50 AM

Quote:

Originally Posted by Radomir (Post 629411)
Jon.. no.. Go back and read post #64 by Marc Hudson... then re-read it 10 more times until you understand the importance of point "B" on the drawing.

Ok, I read that, works great for a simple beam, but not really sure it applies to click type wrenches. I just dont know that much about how they work internally. I will accept that they operate exactly the same as a beam type but they don't, otherwise they would have a pivoting handle to make sure you apply the force at a set point on the wrench. Click type don't have that so I assume they work differently.
PS - I dont have a dog in this fight, just want to know what is correct. I am lucky the wrench I use is exactly 1'. Thank goodness.

erich weaver 02-15-2012 10:05 AM

Quote:

Originally Posted by Radomir (Post 629415)
Either way, you actually don't need to "understand" any of this.. just follow instructions from the manual, or 43.13, or any other publication.. they all show the same formula... there really should be no 100+ posts about this :)

Perhaps, but the reason there are 120 posts about this is because the manufacturer of the tool that is being advertised at the start of this thread has instructed the users that the 0.8 multiplier is a constant for a torque wrench measuring in ft lbs. If that isnt true, then it needs to get sorted out in a convincing way so that the instructions will be corrected. I like to think that most of the posters are trying to contribute toward an effort of understanding and consensus, but perhaps that isnt achievable in a forum such as this.

erich

Radomir 02-15-2012 10:07 AM

You make a good point Erich.. The key here is to understand that this is just another extension.. like any ohter you'd use on your torque wrench.. so I'm suggesting that we stick to what wrench mfgr says, not extensions mfgr :)

Garage Guy 02-15-2012 11:33 AM

Quote:

Originally Posted by jpharrell (Post 629392)
4) If you must use an extension straight in line with the handle of a torque wrench you should be very careful. The torque applied to the bolt will be greater than the value you set on the torque wrench and the correction factor depends on both the length of the extension and the moment arm of the force application. It is not just the length of the torque wrench handle that counts, it is also dependent on where you apply the force on the handle.

This is a really important point. Some of us have been referring to "length of the torque wrench" to mean "how far from the head of the torque wrench you are applying the force", but to be clear it is that distance, not the manufactured length of the wrench, that is important here (assuming a click-type wrench anyway). If you have a 12" torque wrench and for some reason are choking up on it applying the force halfway at 6" from the head, you need use 6" as the torque wrench length in the formula for torque at the business end of the extension. If you add a 12" cheater so you are applying the force at 24" from the head of the wrench, use 24" as the torque wrench length in the formula. If you are applying the force at 12" from the head of the wrench, and using Allan's 3" extension, use a factor of 0.8 :). Beam-type wrenches are designed to be used by applying force at one particular distance from the head, and that's the length you should use.

Of course as Larry and various other folks have been pointing out at length (pun intended, I guess) where you apply the force on the wrench doesn't matter if you are using a click-type wrench in the usual way, without an extension. It will measure the torque at the head of the wrench and that's all you want in that case.

--Paul

WSBuilder 02-15-2012 12:09 PM

Quote:

Originally Posted by Garage Guy (Post 629463)
Beam-type wrenches are designed to be used by applying force at one particular distance from the head, and that's the length you should use.

Recall that most of the old, linear scale, "beam-type" torque wrenches had pivoting handles. The proper procedure is to ensure neither end of the handle comes into contact with the beam so that all the force is applied at a specific location.


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