MHH torque wrench

[LeeElms]

I have an MHH torque wrench which I inherited from my father many years ago. Not really looked at it closely until recently, and I have some questions. I can't locate a manual on the internet.



Does it work by showing you the torque or does it have a feature to release the torque at a set point? There are some screws on the sides, but my guess is that they are for calibration; they don't look like user settings.

The units are shown as 'LB-INS'. Does this mean 'pounds force inch'? If so, it seems the range is quite low, only up to 13.5Nm (less than required for some bicycle fasteners).

 

[Inspector]

Nice little tool. There will not be a click to signify the correct torque has been reached. One of the needles, probably red, would be set using the little knob in the centre of the bezel to the desired torque. The black needle would move as the force you are applying goes up and you would stop when the two needles are aligned. The red needle is only an indicator telling you quickly you have reached the torque and would usually be used when you have a number of fasteners to tighten with the same torque. If you are just doing one or two you just watch the needle reach the number and stop.

It is a pretty simple mechanism and unless abused is pretty accurate and consistent. It is just for small fasteners probably in the 3/8" range as a maximum with 3/16" and 1/4" being the average. The LB-INS is the force of one pound 1" out from the centre of rotation. LB-FT being 12 times more with a force of 1 pound 12" out from centre of rotation.

You do not use your wrench to torque a left hand thread, only right hand, clockwise.

Usual practice if needing to torque near the maximum on the dial you move up to a bigger wrench. IE don't use the last 10% indicated on the dial.

One last thing. Because parallax can give you erroneous readings you want to be directly above the centre of the dial when you read it and not off to the side. I have used 600 FT-LB versions to torque engine mount bolts on aircraft and we would have at least two people. One or two to turn the wrench and one to read the dial.

Pete

 

[Gerry]

it's a simple dial indicating torque wrech. The red needle is rotated to the desired torque using the knob in the centre then you stop when the main needle touches it.
often they have another drive square on the back so you can torque lefthand threads.
There are two screws in the body, One on the side to adjust the reading for calibration and the one on the back is simply a locking screw for that adjuster.
these go out of calibration very quickly and it probably isn't accurate now. I had to calibrate these on a weekly frequency compared to breaking wrenches which could in most cases be done yearly.

Gerry

 

[LeeElms]

Thank you for the information, all useful to know.

 

[Sideways]

Yup. Max torque = 120 inch pounds = 10 lbs force at a distance of 1 foot.
Another way to look at it is equivalent to a decent 20 lb pull at the end of a 6 inch spanner.
So good for lots of smaller fixings rather than cranking on the car wheel nuts.