Technical Doubling the capacity of an inch/lb torque wrench

I've a Mac 0-60 in/lb torque wrench, I need to double the capacity to get fairly accurate at 90 in/lbs. I don't think its as simple as making a 1inch extension, is it?


Edit: Or would I make an extension the same length as the handle?

Thanks

 

The torque-sensing mechanism in the head of your torque wrench (click-type, I assume) is only set up to handle 60 in-lbs. Even if it could withstand 90 in-lbs, how would you know when you got there?

Extending the handle increases the amount of torque you put on the wrench head, but does not change the measurement mechanism.

 

Go buy the correct tool. Not worth taking a chance in damaging the tool that you have .
Vic

 

Here you go.
https://www.norbar.com/Home/Torque-Wrench-Extension-Calculator

 

You might ask at a local auto parts store or tool rental place and see if they have one to loan or rent. I think your idea about the extension should work fine.

Charlie Stephens

 

It’s a beam wrench, I don’t plan to extend the handle, but make an extension for the business end. I know there’s a way if you make an extension, the reading on the wrench will be less by some factor.
No place local has a 100-120 inch pound wrench, all are 0-80 or less.

 

I’d been on Google for a 1/2 hour and never saw that. Lol. Thanks

 

Build an extension for the drive end, to calculate new torque value take the “new” length divided by the original length. This give you the correction factor, divide the original torque value by your correction factor and bingo new lower torque wrench setting


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The correct way is to use a Torque Multiplier, but I doubt they make one that small. Just get the right size Torque Wrench.

 

I have an electronic inch pound extension torque wrench.
Basically its a 3/8 extension that reads torque, it covers the range your looking for.

 

Actually using an extension on a torque wrench is 100% correct if the application warrants it. And the torque setting is adjusted accordingly.


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Oh, I see. We're talking about one of these? I've learnt something.

 

Yes, or a crows foot, when the socket and torque wrench don’t fit somewhere


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And low and behold, going through an old tool box I have, I came across some precision TWs I used to use 30 years ago, they’re on Newton Meters, and pretty sure they have the proper range I need, just have to do the Google calculator thing.
Man, I wonder what else I used to have? Lol.

 

This was my thought/idea. Plan was to use 1x1/8 flat bar, drill holes and sacrifice an extension, weld them in 10.5 inches apart (middle of my little ball handle) then do it.

 

If you have a very accurate foot/pounds torque wrench, just set it to 7.5 ft/lbs.

 

It's really quite simple, not sure why there are so many folks opposed to a little bit of hot rodder ingenuity.

Double the length of your torque wrench and torque to half the value. In other words, if your 60 inch/lb beam torque wrench is 12 inches long from the center of the socket drive to the pivot (or center) on the handle and you need to torque something to 90 inch lbs, make a 12 inch extension from the business end (socket drive) and torque to a reading of 45 (half of 90) on your wrench. You had the right idea all along in your first post.

 

Dividing by 12 is something I could do. But I wouldn’t trust my clicker that low. I’m all in on making an extension. Got held up on another aspect of the job.

Word to the wise. When taking on a repair that renders the vehicle inoperable, don’t park it in front of the vehicle that runs.

 

https://www.amazon.com/TEKTON-Torque-10-150-Lb-13-6-203-5-24335/dp/B00C5ZL2EG?th=1

TEKTON 1/4 Inch Drive Click Torque Wrench (20-200 in.-lb.) | 24320

https://www.harborfreight.com/14-in...MIw5mFucX17wIVTx6tBh3mRwjXEAQYAyABEgI-WvD_BwE



Whole bunch of 1/4" in lb 20-200

 

There you go.
I use to work for an airline and we use to make all different lengths that either were not available or would take too long to order one in.

 

I would just buy the one listed above for $38. Making an extension may calculate out on paper, but you really don't have any way to verify that what you did is accurate when its done. Might be ok for doing something that required a lot of ft/lbs and had a large fudge factor, but with inch lbs I would just buy one.

 

Turns out both of the TWs I mentioned above can work for me, the 1/4 drive one goes to 120 kgf/cm. Google tells me 1 in/lb = 1.15 kgf/cm so a click over 100 should get me where I need to be.

Thanks all

Edit: the real pisser is I’m so tight with a $ I’m doing this myself and the shop only wanted 150 for the labor plus the parts. But I still find something fundamentally wrong with paying for something I can do myself.

 

LOLOL!.....

 

I hear that... One advantage is any screw-ups and/or aggravation don't cost you labor charges! LOLOL...

 

So true, it’s OT what I’m working on, but spent 4 hours yesterday dicking around with a “good tool for the job”. Finally said screw it and had my kid take me to town for the “cheapo plastic tool” which worked immediately.
I did spend a lot more time cleaning things up than a shop would have, so feel okay turning a 1.5 hour job into a weekend of, Er, fun...ya. Fun

 

So if you buy one of those listed, do you then have a way to verify that what you did is accurate?

The answer is no.

By the way, calculating on paper, or using a calculator, are both accurate ways of determining how extension length and torque reading will result in the desired torque for the fastener in question. Math is a proven science, not a guess.

 

It's all good, my 120kgf/cm wrench I uncovered did the treat. I was looking forward to welding things up though...lol

 

The math in the above link is a little easier than the one I normally use when torquing backing plate bolts with solid axle flanges, where an end wrench is needed on the torque wrench.

 

Ebb, what you say is basically true, if the calculations are done correctly and the builder applies it correctly and the extension he uses doesn't flex any........but in my world I always seem to have to deal with Murphy's law. Personally, anything I was assembling that needed the precision of an inch pound torque wrench is going to get done with a professionally made and probably calibrated tool. Yes, it's possible that it is out of calibration, but usually unless someone has abused them, they are pretty close. I just don't think think it's worth the time and effort it takes to figure it all out just to save $40. I post things all the time in the home built tool thread, so I think I am someone who has a strong interest in reusing and adapting things rather than just always buying something. I like to think that many of the tools I make work as well if not better than what I could have bought......I know I'm happy with the results, but often I spend quite a lot of time getting it like I want it. That's why I don't think it's worth the effort for something as inexpensive as a torque wrench. I don't want to dissuade others from building and adapting and modifying because I think it's a great thing to do. My wife and I built our own house when we were young. The idea was not to pay anyone to do anything we could do ourselves, and hopefully have our house paid for when done. One lesson I learned and never forgot was to pick my battles. By that I mean that some things were not worth the effort required when compared with what I saved. Experience is a great teacher.

 

Interesting and I must say, entertaining thread with multiple solutions. Life is short, I agree with everyone.

The OP's original 'what is' posting: "I've a Mac 0-60 in/lb torque wrench, I need to double the capacity to get fairly accurate at 90 in/lbs. I don't think its as simple as making a 1 inch extension, is it?"

"Torque wrench? We don't need no stinking torque wrench!"

If the item in need of torque can be placed in a position where a horizontal beam can be affixed, one can use mass and gravity to obtain a reasonably accurate torque by using a breaker bar marked to 18 inches and suspending a usually brand new 5 pound home gym workout weight at that point...

Moselli

"How do dragons blow out candles?"