Adjusting torque amt when using extensions...
- Thread starter Uncle Ben
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Major Ramifications
Well-known member
There is no torque "lost" when using an extension. The moment arm is still the same.
glenmore
Well-known member
The torque amount changes if you are at an angle to the fastener, hence the need for torque angle gauges.
http://buy1.snapon.com/catalog/tools.asp?tool=all&Group_ID=980&store=snapon-store
To keep it simple just try and be perpendicular and square with your socket, extension and torque wrench.
http://buy1.snapon.com/catalog/tools.asp?tool=all&Group_ID=980&store=snapon-store
To keep it simple just try and be perpendicular and square with your socket, extension and torque wrench.
SMKS
Well-known member
I don't think that is what a torque angle gauge is for. The gauge measures rotation of the bolt.
I believe the gauge is used when a spec calls for something like this:
Tighten to 80 ft-lbs., then an additional 45 degrees.
gj67stang
Well-known member
I don't think that is what a torque angle gauge is for. The gauge measures rotation of the bolt.
I believe the gauge is used when a spec calls for something like this:
Tighten to 80 ft-lbs., then an additional 45 degrees.
Yeah he was way off
I don't think that is what a torque angle gauge is for. The gauge measures rotation of the bolt.
I believe the gauge is used when a spec calls for something like this:
Tighten to 80 ft-lbs., then an additional 45 degrees.
You would be correct. I believe what the OP is referring to is the possibility of the extension acting as a torsion bar and "using up" some of the torque. I have never run the numbers on something like this but my gut feeling is that the mount of torque the extension is going to absorb is going to be minimal.
Kirbot
Well-known member
Some people have even claimed that long extensions will twist and act as a spring and actually add torque.
Personally, I wouldn't worry about it.
Either way, I'm sure the difference would be minimal at best
Farmrod
Well-known member
Let me dig out the books there is an equation you use when applying torque with an extension in the mix ill post back up when i find the equation
Chris
Chris
thesilverone
Well-known member
there was a discussion here last week about this same topic
http://www.garagejournal.com/forum/showthread.php?t=95429&highlight=extension+torque
most notably post number 11 courtesy of larry_g
http://www.garagejournal.com/forum/showthread.php?t=95429&highlight=extension+torque
most notably post number 11 courtesy of larry_g
Farmrod
Well-known member
oops cancel the above statement my book reads like this
"When a standard extension(one that is at right angles to the plane of the wrench) us used with a torque wrench, no torque reading adjustment is required. If a linear extension (one on the same linear plane as the wrench) is used, the mechanical advantage is increased, and the torque reading should be adjusted using the following formula:
TS=TxL1/(L1+L2)
T= torque in lb.-ft.
TS= torque scale in lb.
L1= torque wrench frame length in inches
L2= torque wrench extension length in inches
So if a torque spec is 50 lb.-ft. and an 18" torque wrench is to be used in conjunction with a 12" linear extension, the following calculation would be used to determine what the correct reading on the torque wrench scale should be:
TS= 50x18/(18+12)
TS= 900/30
TS= 30 lb.-ft.
Info from Medium/Heavy Duty Truck Engines, Fuel & Computerized Management Systems 2nd edition
So to answer your question no the torque doesnt change when you use an extension
"When a standard extension(one that is at right angles to the plane of the wrench) us used with a torque wrench, no torque reading adjustment is required. If a linear extension (one on the same linear plane as the wrench) is used, the mechanical advantage is increased, and the torque reading should be adjusted using the following formula:
TS=TxL1/(L1+L2)
T= torque in lb.-ft.
TS= torque scale in lb.
L1= torque wrench frame length in inches
L2= torque wrench extension length in inches
So if a torque spec is 50 lb.-ft. and an 18" torque wrench is to be used in conjunction with a 12" linear extension, the following calculation would be used to determine what the correct reading on the torque wrench scale should be:
TS= 50x18/(18+12)
TS= 900/30
TS= 30 lb.-ft.
Info from Medium/Heavy Duty Truck Engines, Fuel & Computerized Management Systems 2nd edition
So to answer your question no the torque doesnt change when you use an extension
glenmore
Well-known member
I'm glad somebody knows what they are doing here!
Maybe the OP was concerned about extensions parallel to the wrench.
http://www.norbar.com/calculators/torque-wrench-extension-calculator.aspx
Maybe the OP was concerned about extensions parallel to the wrench.
http://www.norbar.com/calculators/torque-wrench-extension-calculator.aspx
diesel research
Well-known member
Good. 1 more myth crushed. Hopefully within a month we will have squashed most of these persistent myths from the shop.
I believe this myth stems a LOT from peoples personal experiences with impact guns, noticing a loss of power. Not the same thing.
One fact we won't get into today, is the fact that even the top notch PI/CDI/Norbar torque wrenches are inherently inaccurate at gauging fastener preload.
"Good enough" for non critical applications such as automotive. Much cheaper than more accurate methods.
I believe this myth stems a LOT from peoples personal experiences with impact guns, noticing a loss of power. Not the same thing.
One fact we won't get into today, is the fact that even the top notch PI/CDI/Norbar torque wrenches are inherently inaccurate at gauging fastener preload.
"Good enough" for non critical applications such as automotive. Much cheaper than more accurate methods.
Well, I had heard a while back that for every extension or adapter (like using a 1/2" to 3/8" socket adapter) that you use you will decrease the amount of torque, as in "lose" torque. Especially if using both an adapter and extension, plus your socket. But I guess that is not the case. Good to know...one less thing to worry about.
I was also wondering about offset sockets attached to your torque wrench, such as an offset 02 sensor, or a crows foot. What kind of affect will that have, not being in line with the torque wrench handle, especially after you start tightening?
Thanks for everyone's help so far.
I was also wondering about offset sockets attached to your torque wrench, such as an offset 02 sensor, or a crows foot. What kind of affect will that have, not being in line with the torque wrench handle, especially after you start tightening?
Thanks for everyone's help so far.
Last edited:
gj67stang
Well-known member
See the link in glenmore's post above.
diesel research
Well-known member
Put them at a 90* offset and the difference is so low as not to matter.
Charles (in GA)
Well-known member
I think the OP was asking about common extensions used between the socket and the ratchet head, such as in a recessed or difficult to reach area, and was NOT asking about offsets and torque adapters.
While extensions, especially long ones will sometimes twist like a torsion bar, there is no correction for this as the torque is still being transmitted to the other end.
Offsets and torque adapters are another subject. You can go to any torque wrench manufacturers web site and find an illustration showing how to do the math to correct for offsets that are parallel to the torque wrench or at some odd angle to it.
Here is a page from an FAA advisory circular showing how to make the corrections.
http://www.garagejournal.com/forum/attachment.php?attachmentid=13389&d=1192502669
Charles
While extensions, especially long ones will sometimes twist like a torsion bar, there is no correction for this as the torque is still being transmitted to the other end.
Offsets and torque adapters are another subject. You can go to any torque wrench manufacturers web site and find an illustration showing how to do the math to correct for offsets that are parallel to the torque wrench or at some odd angle to it.
Here is a page from an FAA advisory circular showing how to make the corrections.
http://www.garagejournal.com/forum/attachment.php?attachmentid=13389&d=1192502669
Charles
caper
Well-known member
This is true if your using an impact wrench.Each time the gun impacts it has to reflex the extensions and adapters but with a torque wrench it's a steady pull and the flex is constant.