TheSamba.com :: View topic

Fri Aug 23, 2013 6:13 am

greebly wrote:
Dorothy, you are using a Pittsburgh tools harbor freight special which means you can put any length of extension you wish and use a cheater pipe without affecting accuracy of the torque applied.

Correct. That is a handle extension. Not sure who Dorothy is, but Diana can safely use that to multiply her strength. The extensions I was referring to go on the business end, and will definitely affect the reading.

RonC

EDIT: Never mind. I know who Dorothy is now...

Quote: Lions, and tigers, and bears! Oh, my!

Fri Aug 23, 2013 7:23 am

greebly wrote: I heard it from my second cousin's ex-wifes's brother that the Navy uses Craftsman torque wrenches that are calibrated to the US National standards Mil-spec and only cost $2000.00 each. Be sure not to use a cheap $3.00 extension on it though as it will magnetically alter the spring tension.
Dorothy, you are using a Pittsburgh tools harbor freight special which means you can put any length of straight extension you wish and use a cheater pipe without affecting accuracy of the torque applied.

That first paragraph sounds pretty dismissive of someone who is trying to contribute information here. I never thought an extension would change the torque value but then again, neither do I think there is nothing I could learn if I keep my ears (eyes, in this case) open. I hope the Navy guy doesn't decide it's not worth clarifying this issue.

Chuey

Fri Aug 23, 2013 7:25 am

greebly wrote: I heard it from my second cousin's ex-wifes's brother that the Navy uses Craftsman torque wrenches that are calibrated to the US National standards Mil-spec and only cost $2000.00 each. Be sure not to use a cheap $3.00 extension on it though as it will magnetically alter the spring tension.
Dorothy, you are using a Pittsburgh tools harbor freight special which means you can put any length of straight extension you wish and use a cheater pipe without affecting accuracy of the torque applied. you heard wrong. but what do i know? i only do this for a living and if its wrong, people die.

Fri Aug 23, 2013 7:28 am

and you're right that it doesnt really matter using a pittsburg wrench on a vw cv joint. (thats what i use at home anyway.) im just stating what i know. this topic was nuked long before i posted.

Fri Aug 23, 2013 7:57 am

snowsyncro wrote: NavyVW wrote: my tech manual wont let me copy and paste and im not gonna type the thing out, but extensions do affect torue value as per the navy manual for structural repair of aircraft

Hmmm...are we taking about the same kind of extensions? Andrew is talking about the typical ratchet extension, the kind that you use to place the ratchet away from the bolt, to get some room to swing it. I agree with him; that should not affect torque if you are holding everything square.

I think the Navy manual may be referring to a different type of extension. One that changes the length, effectively, like a crow's foot or an actual torque wrench extension. Like you would use to torque 200 ft-lb with a 100 ft-lb torque wrench, for example. There are definitely adjustment formulas for those situations.

RonC

There is a fair amount of twist in a 3/8" extension, more with a 9" extension than with a 3" extension, but still very noticeable.

That's what Navy's talking about.

Fri Aug 23, 2013 8:01 am

i was talking about an "axial" extension to be clear.

Fri Aug 23, 2013 8:13 am

Chuey wrote: greebly wrote: I heard it from my second cousin's ex-wifes's brother that the Navy uses Craftsman torque wrenches that are calibrated to the US National standards Mil-spec and only cost $2000.00 each. Be sure not to use a cheap $3.00 extension on it though as it will magnetically alter the spring tension.
Dorothy, you are using a Pittsburgh tools harbor freight special which means you can put any length of straight extension you wish and use a cheater pipe without affecting accuracy of the torque applied.

That first paragraph sounds pretty dismissive of someone who is trying to contribute information here. I never thought an extension would change the torque value but then again, neither do I think there is nothing I could learn if I keep my ears (eyes, in this case) open. I hope the Navy guy doesn't decide it's not worth clarifying this issue.

Chuey
If he has an engineering white paper to post that outlines factually based referenced material then I am willing to entertain it as possibly pertinent. This young woman asked a simple question, for the sake of the CV bolts on a VW Vanagon I do not think it will make a significant, nor an even measurable difference to the torque value to have a 6" extension at 33 ft/lbs. You guys are just hilarious.

Fri Aug 23, 2013 8:20 am

Jake de Villiers wrote:

There is a fair amount of twist in a 3/8" extension, more with a 9" extension than with a 3" extension, but still very noticeable.

That's what Navy's talking about.

Wow you must be using really cheap tools! Where did you buy them? Do you get a quarter turn of twist with your extension? Even if there is a significant amount of slack in the extension to wrench connection as soon as it takes the slack up and exerts torque it will remain the same. This is not rocket construction. Some of you must go through some real angst grocery shopping. So many choices.

Fri Aug 23, 2013 8:49 am

greebly wrote: Chuey wrote: greebly wrote: I heard it from my second cousin's ex-wifes's brother that the Navy uses Craftsman torque wrenches that are calibrated to the US National standards Mil-spec and only cost $2000.00 each. Be sure not to use a cheap $3.00 extension on it though as it will magnetically alter the spring tension.
Dorothy, you are using a Pittsburgh tools harbor freight special which means you can put any length of straight extension you wish and use a cheater pipe without affecting accuracy of the torque applied.

That first paragraph sounds pretty dismissive of someone who is trying to contribute information here. I never thought an extension would change the torque value but then again, neither do I think there is nothing I could learn if I keep my ears (eyes, in this case) open. I hope the Navy guy doesn't decide it's not worth clarifying this issue.

Chuey
If he has an engineering white paper to post that outlines factually based referenced material then I am willing to entertain it as possibly pertinent. This young woman asked a simple question, for the sake of the CV bolts on a VW Vanagon I do not think it will make a significant, nor an even measurable difference to the torque value to have a 6" extension at 33 ft/lbs. You guys are just hilarious.
"for official use only". sorry, bud. like i said, this was nuked LONG before i posted. i just wanted to throw a little wrench in the conversation. (with a 6" extension to get you going)

Fri Aug 23, 2013 8:56 am

This might be it. Just a guess though.

http://navyaviation.tpub.com/14018/css/14018_128.htm

RonC

Fri Aug 23, 2013 9:19 am

Look at the referenced diagram and you will see that the extension labeled Ea is at a right angle to the wrench. It is not a perpendicular 3/8 or 1/2" socket extension.
http://navyaviation.tpub.com/14018/css/14018_127.htm

Fri Aug 23, 2013 9:32 am

It's amazing the number of professionals I've met who think that just because they are wrong and get paid for it or have been wrong for a lot of years, that makes them right and not just right, but so right that they use the fact that they get paid for being wrong or the number of years that they have been wrong as definitive 'proof' that they are right.

Fri Aug 23, 2013 9:53 am

With a long enough extension, there can be some detectable torsional twist, however the torque is still transmitted to the fastener. You can think of the extension as a torsional spring (or torsion bar if that is more familiar).

It is similar to if you lay down and put a spring on your chest and then a 150Lb person stands on the spring. Yeah, the spring will compress as he stands on the spring, but you will certainly feel his entire 150 lbs on you. Try it, but I suggest putting a spring on a scale and weighing yourself for the experiment :wink:

Likewise the torsional spring, the extension, could have some twist, but if you apply 50Nm, that is what is applied to the bolt (or more accurately resisted by the bolt).
Still, it is good practice to use as short of an extension as possible, mainly for alignment, which can affect the accuracy of the reading.

This is for statically applied loads; impact drivers and fast power tools with a clutch will be a different scenario. Just like if someone quickly stepped on and off that spring on your chest- (I told you to use a scale!) :lol: .

Fri Aug 23, 2013 10:16 am

Andrew A. Libby wrote: It's amazing the number of professionals I've met who think that just because they are wrong and get paid for it or have been wrong for a lot of years, that makes them right and not just right, but so right that they use the fact that they get paid for being wrong or the number of years that they have been wrong as definitive 'proof' that they are right.

I love you Andrew! That's perfect!