How does a torque wrench work?

Well that just sucks!

 

A whiny wheel usually means a bad wheel bearing

 

A whiny wheel usually means a bad wheel bearing

 

I made a lot of half-assed attempts to setup a cheap calibration
checker for my torque wrench using a gallon of water for a weight and
a measured lever arm, attached to a bolt that i could stick in a
socket attached to the wrench, pivoted relatively freely on something,
so I could see with a given torque load, at what setting the wrench
started with the click. Never got it working, though. But doesn't it
seem like something you could do at home easily, if you were less of a
klutz than I?

 

I made a lot of half-assed attempts to setup a cheap calibration
checker for my torque wrench using a gallon of water for a weight and
a measured lever arm, attached to a bolt that i could stick in a
socket attached to the wrench, pivoted relatively freely on something,
so I could see with a given torque load, at what setting the wrench
started with the click. Never got it working, though. But doesn't it
seem like something you could do at home easily, if you were less of a
klutz than I?

 

That's an interesting idea (I mean making the comparison, not you being
a klutz).

I had a bit of a think about it, and it really seems quite simple:
Immobilize one wrench in such a way as not to interfere with its action,
then hook another one up to it via the usual square drive.

http://www.tegger.com/hondafaq/misc/torque_wrench_comparing_1.jpg
http://www.tegger.com/hondafaq/misc/torque_wrench_comparing_2.jpg

Each wrench has a 1/2" to 3/8" adapter, then a 10mm socket, then a
section of 10mmm Allen rod connects the two.

I've barely got the click one clamped in, just tight enough to keep it
from falling through the vise. A quick measurement with a micrometer
shows no apparent distortion of the tube. Then I placed my hand on the
square drive end of the beam-type, just like you would if tightening a
bolt with extensions on the torque wrench.

Remember that the click-type's mechanism is internal to the tube. So
long as I do not interfere with the head's pivot pin or the tilt
mechanism inside, the readings should be unaffected by the vise.

I had the click-type set to only 30 ft lbs, so as to minimize any
malevolent forces should something slip.

The click-type wrench clicked as the beam type approached 30 lbs, but it
always clicked a couple of pounds short of 30 on the beam's reading.
Tolerance on the click-type is given as 4% up or down, so theoretically
a reading of 30 could actually mean anywhere between 28.8 to 31.2. And
heaven only knows what the tolerance is on my 35 year-old beam-type.

 

That's an interesting idea (I mean making the comparison, not you being
a klutz).

I had a bit of a think about it, and it really seems quite simple:
Immobilize one wrench in such a way as not to interfere with its action,
then hook another one up to it via the usual square drive.

http://www.tegger.com/hondafaq/misc/torque_wrench_comparing_1.jpg
http://www.tegger.com/hondafaq/misc/torque_wrench_comparing_2.jpg

Each wrench has a 1/2" to 3/8" adapter, then a 10mm socket, then a
section of 10mmm Allen rod connects the two.

I've barely got the click one clamped in, just tight enough to keep it
from falling through the vise. A quick measurement with a micrometer
shows no apparent distortion of the tube. Then I placed my hand on the
square drive end of the beam-type, just like you would if tightening a
bolt with extensions on the torque wrench.

Remember that the click-type's mechanism is internal to the tube. So
long as I do not interfere with the head's pivot pin or the tilt
mechanism inside, the readings should be unaffected by the vise.

I had the click-type set to only 30 ft lbs, so as to minimize any
malevolent forces should something slip.

The click-type wrench clicked as the beam type approached 30 lbs, but it
always clicked a couple of pounds short of 30 on the beam's reading.
Tolerance on the click-type is given as 4% up or down, so theoretically
a reading of 30 could actually mean anywhere between 28.8 to 31.2. And
heaven only knows what the tolerance is on my 35 year-old beam-type.

 

Huh. I sent a reply a couple of hours ago but it foes not seem to have
shown up anywhere. Here it is again:

That's an interesting idea (I mean making the comparison, not you being
a klutz).

I had a bit of a think about it, and it really seems quite simple:
Immobilize one wrench in such a way as not to interfere with its action,
then hook another one up to it via the usual square drive.

http://www.tegger.com/hondafaq/misc/torque_wrench_comparing_1.jpg
http://www.tegger.com/hondafaq/misc/torque_wrench_comparing_2.jpg

Each wrench has a 1/2" to 3/8" adapter, then a 10mm socket, then a
section of 10mmm Allen rod connects the two.

I've barely got the click one clamped in, just tight enough to keep it
from falling through the vise. A quick measurement with a micrometer
shows no apparent distortion of the tube. Then I placed my hand on the
square drive end of the beam-type, just like you would if tightening a
bolt with extensions on the torque wrench.

Remember that the click-type's mechanism is internal to the tube. So
long as I do not interfere with the head's pivot pin or the tilt
mechanism inside, the readings should be unaffected by the vise.

I had the click-type set to only 30 ft lbs, so as to minimize any
malevolent forces should something slip.

The click-type wrench clicked as the beam type approached 30 lbs, but it
always clicked a couple of pounds short of 30 on the beam's reading.
Tolerance on the click-type is given as 4% up or down, so theoretically
a reading of 30 could actually mean anywhere between 28.8 to 31.2. And
heaven only knows what the tolerance is on my 35 year-old beam-type.

 

Huh. I sent a reply a couple of hours ago but it foes not seem to have
shown up anywhere. Here it is again:

That's an interesting idea (I mean making the comparison, not you being
a klutz).

I had a bit of a think about it, and it really seems quite simple:
Immobilize one wrench in such a way as not to interfere with its action,
then hook another one up to it via the usual square drive.

http://www.tegger.com/hondafaq/misc/torque_wrench_comparing_1.jpg
http://www.tegger.com/hondafaq/misc/torque_wrench_comparing_2.jpg

Each wrench has a 1/2" to 3/8" adapter, then a 10mm socket, then a
section of 10mmm Allen rod connects the two.

I've barely got the click one clamped in, just tight enough to keep it
from falling through the vise. A quick measurement with a micrometer
shows no apparent distortion of the tube. Then I placed my hand on the
square drive end of the beam-type, just like you would if tightening a
bolt with extensions on the torque wrench.

Remember that the click-type's mechanism is internal to the tube. So
long as I do not interfere with the head's pivot pin or the tilt
mechanism inside, the readings should be unaffected by the vise.

I had the click-type set to only 30 ft lbs, so as to minimize any
malevolent forces should something slip.

The click-type wrench clicked as the beam type approached 30 lbs, but it
always clicked a couple of pounds short of 30 on the beam's reading.
Tolerance on the click-type is given as 4% up or down, so theoretically
a reading of 30 could actually mean anywhere between 28.8 to 31.2. And
heaven only knows what the tolerance is on my 35 year-old beam-type.

 

immobilize your wrench handle,place a foot-long wrench(breaker bar?)or
lever on the sq.drive part,and use a digital spring scale (like fishermen
use to weigh their catches)to put force on the other end of the wrench.
Read the ft.lbs off the digital scale.If you have the lever in the vertical
plane(pulling sideways with the scale),you eliminate the lever's weight
from your measurement.

You can buy digital fish scales at Wal-Mart,IIRC,around $20 USD.

 

I have a question. How important is accuracy on a Torque Wrench? I mean,
consistency seems more important to me. If you are torqueing your lug nuts
to 85 lbs, and the wrench is off a little, you still get all the lugs
torqued to an even setting that keeps you from warping rotors. I guess on
smaller items you may want to be a little more precise. I have a small
Husky wrench that does inch lbs.

I have a couple of torque wrenches. We took a socket and hooked them
together once and set them to the same setting. Then we put pressure on
them and they both clicked at almost the same time. So they are "close" for
sure.

I'l love to have a Snap-on model. I'm a real tool whore

G-Man

 

I have a question. How important is accuracy on a Torque Wrench? I mean,
consistency seems more important to me. If you are torqueing your lug nuts
to 85 lbs, and the wrench is off a little, you still get all the lugs
torqued to an even setting that keeps you from warping rotors. I guess on
smaller items you may want to be a little more precise. I have a small
Husky wrench that does inch lbs.

I have a couple of torque wrenches. We took a socket and hooked them
together once and set them to the same setting. Then we put pressure on
them and they both clicked at almost the same time. So they are "close" for
sure.

I'l love to have a Snap-on model. I'm a real tool whore

G-Man

 

I have a question. How important is accuracy on a Torque Wrench? I mean,
consistency seems more important to me. If you are torqueing your lug nuts
to 85 lbs, and the wrench is off a little, you still get all the lugs
torqued to an even setting that keeps you from warping rotors. I guess on
smaller items you may want to be a little more precise. I have a small
Husky wrench that does inch lbs.

I have a couple of torque wrenches. We took a socket and hooked them
together once and set them to the same setting. Then we put pressure on
them and they both clicked at almost the same time. So they are "close" for
sure.

I'd love to have a Snap-on model. I'm a real tool whore

G-Man

 

I have a question. How important is accuracy on a Torque Wrench? I mean,
consistency seems more important to me. If you are torqueing your lug nuts
to 85 lbs, and the wrench is off a little, you still get all the lugs
torqued to an even setting that keeps you from warping rotors. I guess on
smaller items you may want to be a little more precise. I have a small
Husky wrench that does inch lbs.

I have a couple of torque wrenches. We took a socket and hooked them
together once and set them to the same setting. Then we put pressure on
them and they both clicked at almost the same time. So they are "close" for
sure.

I'd love to have a Snap-on model. I'm a real tool whore

G-Man

 

BTW,you can also cut a strip of wood or plastic for a lever,with a square
hole to fit the drive square.
Measure 12 inches from the *center* of the sq.drive to the point where the
scale attaches to the lever.The lever itself can be a bit longer than
12",the scale to drive center has to be 12",or you have to calculate your
ft-lbs.

 

But how do you KNOW it's only off "a little"?
Maybe it's gummed up or has a chip stuck in it,and it's way off,or
inconsistent.

I used a torque screwdriver at my last job[in-lbs].(Tektronix)

In the USAF Precision Measurement Equipment labs,we had torque wrench
calibrators;the machine did all the work!

 

Not *that* important, but...it depends on the application.

Most automotive fasteners of any importance have substantial built-in
safety factors. Some do not, such as cam bearing cap bolts. Those only
torque to seven foot pounds, a lot lower than many people are used to
working with. Overtorque those enough and big trouble can surface.

It is. Especially with stuff like head gaskets.

Uneven nut torque is not nearly as significant a factor for brake
vibration as some other things.

A LOT more precise. The smaller, the more fragile the threads.

I own just one Snap-On tool, a 12mm six point combo wrench. Let me tell
you, after spending $35 on it, that thing gets the goose-down treatment.

I just like doing work properly. Tighten enough bolts and you eventually
acquire a "feel" for the "right" torque. This works in most cases, and
is necessary in situations where you have no room for the bulk of a
torque wrench. For the rest, I use the torque wrench.

I have neither broken a bolt nor had one come loose on me, since about
1985.

I did overtighten the auto tranny oil pan drain bolt (a very small bolt)
on my wife's '99 Tercel two years ago. The threads on the bolt shifted,
resulting in the need to replace the bolt. Luckily, the bolt threads
were softer than the pan threads, so a new bolt was all that was
required. I have been much more careful since.

 

Not *that* important, but...it depends on the application.

Most automotive fasteners of any importance have substantial built-in
safety factors. Some do not, such as cam bearing cap bolts. Those only
torque to seven foot pounds, a lot lower than many people are used to
working with. Overtorque those enough and big trouble can surface.

It is. Especially with stuff like head gaskets.

Uneven nut torque is not nearly as significant a factor for brake
vibration as some other things.

A LOT more precise. The smaller, the more fragile the threads.

I own just one Snap-On tool, a 12mm six point combo wrench. Let me tell
you, after spending $35 on it, that thing gets the goose-down treatment.

I just like doing work properly. Tighten enough bolts and you eventually
acquire a "feel" for the "right" torque. This works in most cases, and
is necessary in situations where you have no room for the bulk of a
torque wrench. For the rest, I use the torque wrench.

I have neither broken a bolt nor had one come loose on me, since about
1985.

I did overtighten the auto tranny oil pan drain bolt (a very small bolt)
on my wife's '99 Tercel two years ago. The threads on the bolt shifted,
resulting in the need to replace the bolt. Luckily, the bolt threads
were softer than the pan threads, so a new bolt was all that was
required. I have been much more careful since.

 

No, it doesn't apply to torque wrenches. I asked when my took a tumble
down a flight of stairs (in the packaging). But, it's still close to my
other one, so it's probably okay.

 

Thats cool I didnt know.