OK, I do not have a torque wrench yet and I know that this is an important tool that I will need to get. I buy tools that I can use but not nice ones and I went by Wal-Mart and they did not even sell any so I guess I will probably buy one online. My questions has to do with a socket wrench in general. At what length socket arm ar you basically at a 1:1 torque ratio? At what length arm does 10lbs of force on the end equal 10lbs of force at the socket? I know I could grab my physics book and figure it out, but I know one of you guys knows offt he top of your head. I need to torque down a few bolts right now and I got a good idea of how much pressure I am exerting but I do not know how much force that is equaling at the socket end.

Thanks Guys

 

A torque wrench is an engineered device that applies a determined amount of force at a determined distance from the center of the application, known as the moment. Most Torque wrenches are adjustable, and allow the user to change the set point to reach the desired application of torque, or twist. There are many factors that determine the amount of force needed to properly "torque" a fastener. One is the grade of fastener, the other is the stress area. If you have a bolt that is say capable of withstanding say, 118 kips of tension, that is O.K. But you have to calculate the stress area, wich is the actual area of the threads. Thare is also the designed torque application, that is to say, dry, or lubricated threads, you will get a greater amount of force applied with lubricated threads. There is an accepted method of force application, known as "turn of the nut" That method is usually used by the Navy, of Dept. of Defense, it basically has the operator "snug" the nut, or bolt, and add an additional 1'2 turn or whatever the need may be.
It is important not to over stress a fastener, and force it into plastic deformation, because then the fastener may fail without warning. The elasticity of the material is what retains the fastener by the material always wanting to relax, If is goes beyond the " modulous of elasticity" it no longer acts predictably, last but not least, your arm is not a calibrated instrument, so thats the real problem. Tight to you may not be tight to me. Buy a high quality torque wrench, preferrably Snap-On! See ya!

 

Torque is a simple formula, force times distance. If the force is in lbs and the distance is in feet, than the units are ft-lb or lb-ft. If you push down on a socket wrench or breaker bar with 10 lbs of force at a distance of 12" form the socket, you are applying 10 ft-lb of torque.If you put a cheater bar on your wrench and apply 5 lbs of force at a distance of 24" (2ft), you are applying the same 10 ft-lb of torque. You can get a cheap, but functional clicker type torque wrench at Harbor freight for $20, at sears for about $60. YOu can buy a very high quality unit for $150. They are delicate instruments and need to be handled with care. They should be turned down to the lowest setting after use and put back in its case, and not left in a very cold envirement. If you live near a Costco,and you ask the Tire Center Manager nicely, and he may let you check the accuracy of your wrench on his torque analyzer. I usually will if I'm not busy.

 

its easy to check the torque wrench settings...just tighten known bolts unitl they break and note the breaking point, it will almost always be twice there SAE rating. this was actually a 6th grade science project of my sons and we did the full range of SAE diameters and grades and got the same results each time

 

Thats what I needed to know. I cannot belive that I did not remember torque is force times distance. I know MANY other factors are involved as Ringer pointed out and I will be getting an actual torque wrench online as my local options are very limited, but I wanted a way to get a general idea right now using a small 8" wrench.

Thanks all and welcome to the forum Ringer.

 

Hey Ringer, I think you and I took the same engineering classes on plastic and elastic deformation, all that stuff brings me back. For you laymen, just think of a bolt as a spring. It must remain springy to do its job. Torque specs are just an indirect way of measuring bolt stretch, in fact, the super high performance guys don't use a torque wrench to tighten rod bolts, they tighten to a recommended bolt stretch which they measure.

 

Elongation is the most accurate, but that's a whole different ramble!

 

you don't need to go online if you're in a hurry. Most decent car parts places will carry a torque wrench (Napa does in my little town).

 

I'll bet that if you asked there is a forum member near you with a torque wrench you can borrow. You might even get a helper.

Bill

 

Caught my kid taking lug nuts off his Neon with my Snap-On TW the other day........ Guess he wasn't schooled right.......

 

Go to http://hti.org for info on hand tool manufactures. Go to the list of manufactures to see various manufactures web sites.

CDI has info in their FAQ's and Tech Facts that might answer some of your questions. All the other manufactures have information also.

No matter what brand of Clik-Style Torque Wrench you buy always back off the setting To Zero when you are done using it.

Good Luck

 

Or just find a Sears store.

 

I was kind of in the market for a TW...ummm, Advanced Auto (right up the road from me) has a 3/8" click-type for 42 bucks and change...is that something that might be a piece of junk? or would it fit the bill for (very) occational use..says it'll register 40-80 ft.lbs. I believe I would start with checking my intake bolts...
Thanks

 

What do you do for bolts that have a torque spec of like 10? Are there different torque wrench with different ranges or are most in the 40-80 range?

 

I have several sizes and ranges. From a 1/4" drive rated in Inch-Ounces to the 3/8" and 1/2" drive rated in Ft-Lbs. There is also my inch-Lbs in 1/4" and 3/8" drives. I have them calibrated an a yearly basis.

Buy a premium quality tool and you will only need to buy it once. Buy a POS and you will never be satisfied with it

The comments about reducing the value of a click type to its lowest is good advice as is the idea to bring them in from garage for the winter.

 

OK, that said, you're suggesting I purchase, say, a Craftsman TW as opposed to the "Powerbuilt" at Advanced? or would the type with an arrow on a meter (non-click) that goes from 0 to 140 ft lbs be better? Keep in mind, maybe, if I get REAL ambitious, I'll use this TW once a year, I don't own a repair garage, strickly back yard work on my prize possession...ahem...when it needs it...I should still drop a ton o' dough on this wrench??

 

money spent on tools is never really wasted. sounds like a cliche i know but it is true. most tools will save thier price in one use compared to a shop and even more so when compared to using the wrong one and fubaring the job. for what it's worth i have both click and pointer type. i like the pointer ones for jobs where you have to tighten multiple bolts in increments. no resetting just keep going.

 

I bought a new TW yesterday at Home Depot.1/2"- 50-250 ft/lb with lifetiem garantee vs Sears 90 day. It was worth the $70. The one I would like to get is a Snap-On dial ft/lb wrench, like the in/lb one I have.
Gary

 

It is difficult to be very precise with a pointer type wrench.

Buy the click type, use it, and return it. he he he.

 

I have a 3/8 Snap-On clicker type (w/o ratchet) that I bought on Ebay for $82. You can get an inexpensive beam type for much less. A beam type is fine for ocassional use.