(800) 853-2651
SHOP NOW

Torque wrench

S

Slowpoke

Well-known Member
I need to torque a nut to 9-11 ftlbs but can only use a crowfoot on the nut. How do I figure the torque if the center of the nut is 1" from the center of the 3/8 square drive on the wrench? Or is the distance too small for concern?

Thanks
 
(quoted from post at 00:54:08 12/19/12) I need to torque a nut to 9-11 ftlbs but can only use a crowfoot on the nut. How do I figure the torque if the center of the nut is 1" from the center of the 3/8 square drive on the wrench? Or is the distance too small for concern?

Thanks
Click to expand...

You need to measure the distance from the center of the square drive on the end of the wrench to the center of the handle where you are applying the torque and figure the ratio to the length of the extension. For example if the wrench measures 10 inches the ratio is 1/10. In that case you would reduce the torque measured on the wrench by one tenth.

It is much easier to just attach the crow foot extension at a 90° angle to the wrench and then use the listed torque. With a 1 inch extension at a 90° angle to the wrench the difference in length between the center of the handle and the center of the crow foot compared to the actual effective length of the wrench is very small.
 
You could grip the wrench an inch closer to the pivot, but for that issue, I wouldn't worry about it. I can't think of an instance where we grip right on the end of the wrench anyway.
 
OK, I have one of those for the heavy torks, like up to 400 lbs, but I think the principle is the same...we grab and pull with the whole hand, sometimes both, covering several inches of the handle. I think a purist would attach a cable to the handle, 12 inches from the pivot, if measuring foot/lbs, and pull. and die, but being PC, LOL
 
One inch won"t matter enough to worry about, as others have stated. Owen is on the right path to figuring out the formula though. I have it written down at work, but you could Google it and find out for sure.
 
Owen has it pretty much right. Torque is measured by force applied and the distance from application (the lever arm or in this case the distance from the center line of the fastener being turned to the device being used, the torque wrench) With a clicker type torque wrench, it really doesn't matter where you grip the wrench. It will matter how much extra distance you are adding with the crowsfoot socket. As mention above, having the socket offset 90 degrees will pretty much negate any error from the socket. Many torque wrenches are not that accurate and I think that if you pick a torque in the middle of the value required, you will be pretty safe.
 
I needed to do that once. I turned the crow foot so it was out the side, then the torque is the same, the lenght of the torque wrench is not any longer.

If the crow foot is 1" long, and you put it stright out, and the torque wrench is 12" long then you have increased the torque on the nut 1/12. So if you set the wrench at 100 lb. then it would be 112 lb. of torque that you applied.

Dusty
 
I tend to agree with Pentex. When you think about it 9-11 is close to a 20% spread. Adding an inch to a 12" lever is something less than a 10% change. Stick the crows foot on sticking out and use the top end of the spec, or turned back at you and use the bottom. Turning it to 90 degrees also works but to nit pick that is not exactly the same either (I know really nit picking that point) Bottom lie is torque doesn"t keep the fastener tight, stretch does and many factors affect how much stretch you obtain at "X" torque. This was all beat into my feeble brain on a critical application where we left the torque wrenches in the box and had to obtain a certain stretch as measured with a mircometer. Bolts were Boron and the applied torque was unbelievable for the diameter.
 

The formula is:

Tw = (Ta x L) / (L + E)

Where:

Tw is the torque indicated on the wrench
Ta is the torque applied at the adaptor
L is the lever length of the torque wrench
E is the lever length of the adaptor

Note, all lenghts are center to center.

In your case to apply 10 ft-lbs; (10 x 12) / (12 + 1) = 120 / 13 = 9.23. Therefore setting the wrench to 9.23 ft-lbs would apply 10 ft-lbs at the bolt.

Also, positioning the adaptor at a right angle to the wrench requires no adjustment to the wrench setting as previously posted.
 
You must log in or register to reply here.

Similar threads

Horsez2
Buying a Torque Wrench... First Time!
2
Replies
24
Views
955
jaoneill
J
B
How do you break a ratchet wrench?
2 3
Replies
50
Views
2K
NDIHC
N
T
Which impact wrench to buy?
2
Replies
31
Views
2K
WNYBill
W
showcrop
Free torque wrench
Replies
17
Views
2K
jimg.allentown
J
T
How to loosen a stuck flare nut on a fuel line
2 3
Replies
53
Views
3K
rustred
rustred
Tractor Parts Tractor Manuals

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Copyright © 1997-2024 Yesterday's Tractor Co.

All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.

Yesterday's Tractors - Antique Tractor Headquarters
Website Accessibility Policy

Back
Top