Torque wrench capacity extensions

[cavitate]

I have 250ft/lbs adjustable torque wrench. I need to torque a device to 450ft/lbs. I can buy a torque adapter extension.
I have no problem with the math to compute the torque, what I don't see is how do I get the length of the of the torque wrench?
I know from the center of the socket, but I don't where the (fulcrum?) point is, especial on a click type torque wrench.
Thanks, Mikek

 

[3DDave]

The fulcrum is the center of the socket. The part that clicks is just part of the lever and is calibrated to measure the torque at the socket.

In the beam torque wrench I have the handle grip is on a pivot to ensure the load that is applied is at a known distance from the fulcrum. The distance from the handle grip pivot to the center of the socket is what is used to calculate the actual force being applied to get the torque. In beam torque wrenches the bending of the beam for a given applied load, and the source of the measurement, depends on where on the beam that load is applied; hence the pivot.


That distance mainly matters for use with devices that change where the torque is applied to the nut/bolt/fastener other than the designed location on the torque wrench, which seems to be your case.

Look to see if there is a similar pivot on the wrench you have. Otherwise you need to pick a spot to apply the load and use a known force to see what the torque wrench registers or, for a click type, measure the load at that point required to get the set torque, perhaps with a spring scale and a loop of cord held at 90º to the bar.

 

[TugboatEng]

A torque multiplier is an off the shelf solution to your problem.

 

[3DDave]

On the subject of torque multipliers, these guys have a sense of humor and the test equipment to back it up.

Torque Test Channel

https://www.youtube.com/watch?v=npM78T3SrH0

Hand Turn 5,000ft-lbs?! $60 vs $4,000 Torque Multiplier


Multipliers need a place to brace themselves and often apply a far greater side load than the wrench does. Not a bad tool to have, but sometimes a length of cheap pipe is all that is required.

Or putting a scissors jack under the cross-wrench after some moron banged the lug nuts on with an impact driver. It should not take over 300 ft-pounds to loosen an 80 foot-pound-required nut, but that's what that repair shop will never see my car again did.

 

[TugboatEng]

Electro Motive supplies multipliers for tightening the "crab nuts" that secure the power assembly in their engine block. The supplied unit has a ratio of 20.25:1 to give a real 18:1 multiplication.

 

[mfgenggear]

It's interesting subject and as a home mechanic for most of my simple lifespan.
As a young mechanic I broke all the rules.
Disassembling and reassembling countless
Vehicles, engines , motorcycles, small engines and on . Never use to use a Torque wrench. Of course I know better now.
However it seems that back then mechanics was much strait forward and much easier.
Bolts and nuts never broke or came loose. And not common to have issues.
These days Torque wrench, and loctite are your friend. Even torqued bolts and nuts will vibrate loose. And assemblies are more
Complex, and more or can be more difficult to access. After so many years of hands on a person obtains a feel for Torque of hardware.you obtain the feel of the metal has reached its Torque capacity. Now it can be argued and rightly so. But just like any
Skill some are better at it.
The cheater pipe or tube was a common
Tool. , as well as the brass rods, an copper tubing in the tool box.
Cheater tube are a must to change a tire
For removing those over torqued lug nuts, using impact drivers. Every mechanic should get a lessons why nuts and bolts are torqued on and not just impact wrench on.

 

[mfgenggear]

I watched that video while back, and was amazed in the lack of calibration or not precise Torque values . Keep in mind an old style non click Torque wrench unless careless damage never loses calibration.
And it is in my tool box to this day.
My mechanic days are been less and less these days.