Torque wrench question

[MRS]

I was replacing transom shift cable (OMC) yesterday torque at 35 f lb's. I was useing a crows foot only way to get wrench on nut(brass) thought it was getting a little to tight and it did snapped head off. Not sure if cable was faulty or torque wrench bad or does useing the crows foot add more torque. Thanks for any replys plus will not torque next one just tighten by hand.

 

[Tim Frank]

Re: Torque wrench question

I'm guessing from your description, (not entirely getting a good picture of using a crow's foot with a torque wrench) and what I call a crows foot that the pivot point is no longer coaxial with the torque wrench drive and you are actually getting some mechanical advantage that increases the effective torque beyond what the wrench "perceives".

We'll see what others weigh-in with.....or as Winston Churchill (and maybe JB ) might prefer "we shall see in with what others weigh".

 

[halfmoa]

Re: Torque wrench question

You gained torque. There's a formula and calculators for that.

You know what they say about experience...first the test, then the lesson.

 

[MRS]

Re: Torque wrench question

Thanks guys that is the setup I used. But I am not the sharpist nail in the bin so at 35 ft. lb's with the crows foot on how much over was I ?
Test is over ready for the lesson. :facepalm:

 

[Tim Frank]

Re: Torque wrench question

My guess would be ~ 20% +/-....depends on actual dimensions/size of your torque wrench and crows foot

 

[halfmoa]

Re: Torque wrench question

Thanks guys that is the setup I used. But I am not the sharpist nail in the bin so at 35 ft. lb's with the crows foot on how much over was I ?
Test is over ready for the lesson. :facepalm:

To answer that you need a few more figures.
1. What's the length of your wrench from the center of the handle to the center of the ratchet head in inches?
2. What's the length of the crows foot from the center of the drive hole to the approximate center in inches?

Your desired torque was 35ftlbs. Assuming your wrench length is 12" and the crows foot was approximately 1 inch you should've set your wrench at 32.3077ftlbs. You were about 8% over using those assumed figures. If you reply back with your figures I'll tally it up exactly for you.

 

[dolluper]

Re: Torque wrench question

You were about 3 fingers to much

 

[MRS]

Re: Torque wrench question

Thanks guys my neighbor is a machinist showed him what I did and my setup. It was a 1/2 torque wrench with the 1/2 to 3/8 adapter to the 3/8 crows foot said I was close to 10 lb.s over. . Next time will ask first and torque if I add things to the wrench.... Thanks for the reply's I am still learning life's lessons.

 

[BlkY2k]

Re: Torque wrench question

Dont feel to bad, I`m working on the kids car here and everything is in in/lbs. The admiral still hasn`t seen the bill on that new snap on 1/4 in drive torque wrench yet.

 

[MRS]

Re: Torque wrench question

Dont feel to bad, I`m working on the kids car here and everything is in in/lbs. The admiral still hasn`t seen the bill on that new snap on 1/4 in drive torque wrench yet.

Nice love snap on stuff, well at least got the boat all cleaned up so when cable gets here can put together and take her out for a day of fishing.
Good luck with the Admiral nice tools and nice $ but well worth them.

 

[levittownnick]

Re: Torque wrench question

Torque wrenches are not known to be highly accurate devices, something like 10 to 20 %. What comes to mind is that the torque spec could have been mis-interpeted from "inch-pounds" to "foot-pounds" wich would be a multipication factor of 12. (Hope that I am wrong.)

Good luck
Nick

 

[stackz]

Re: Torque wrench question

yeah and most people dont ever send their torque wrenches off to be periodically recalibrated. they'll just buy it and use it as is for 30 years. they do need to be recalibrated every so often. especially the ones with the dials on the handle end.

 

[bruceb58]

Re: Torque wrench question

Torque wrenches are not known to be highly accurate devices, something like 10 to 20 %.

If you have a torque wrench that is off by 20%, time to throw it in the trash.

 

[MRS]

Re: Torque wrench question

It was ft. lbs. not in. and where would you take a torque wrench to get it calibrated? I would love to have it checked.

 

[BlkY2k]

Re: Torque wrench question

Most tool companys have resources to recalibrate such as snap-on, or mac. There are other independant co. that can do it but it isnt cheap. Run a google search you should find some. Heres a video that does a pretty good job of showing a diy test.
http://www.youtube.com/watch?v=RUD81N_TlS8

 

[MRS]

Re: Torque wrench question

Blk, Thanks for the video I am going to check mine out that way will give me piece of mind to know if it is close or wrong. Thanks again...

 

[MRS]

Update Torque wrench question

Update Torque wrench question

OK checked wrench with friends it is good used it almost have boat back together on my way out to put outdrive on. It looked like the brass fitting was digging into the pivot housing when it broke so maybe I need to pay more attention and keep my classes on when working with tools. :facepalm:
Thanks for all the replys...

 

[foodfisher]

Re: Update Torque wrench question

Re: Update Torque wrench question

My torque wrench has a pointer that moves as the bar curves. Calibration is bending the pointer to zero pre torqueing. Trustable or scrap metal?

 

[MRS]

Re: Update Torque wrench question

Re: Update Torque wrench question

I also have one like that love it but cannot fit into all spots I need to use. So have to use the ratchet type sometimes.

 

[Outsider]

Re: Update Torque wrench question

Re: Update Torque wrench question

What's a crow's foot? My wife says I have every tool known to man ...