What to look for in torque wrench? - PeachParts Mercedes-Benz Forum

tyl604 · #1 08-11-2008, 12:43 PM

I found a outlet store in Foley, AL, which has Makita, DeWalt, etc. tools and need a torque wrench. They have several styles. Cheap ones where you twist the handle to a gross setting, then lock it and move right or left for 1 ft pound(?) increments. The first one I tried would not even work. What should I look for in a torque wrench? Is 3/8 OK or should I go for a half inch drive? Am I looking for one which "clicks" when the torque is reached - or is that the way they all work? Am I looking for a twist setting on the head instead of the handle? Am I looking for one with an arm that moves like the hand on a speedometer? What about brand preference? Is bigger better?

Have never used a torque wrench. Comments appreciated.

bgkast · #2 08-11-2008, 12:55 PM

Go for 1/2". I have a craftsman that you pull and twist the handle to set the torque. Look for one that has both ft*lbs and N*m. There are two common types, the click type and the "bending" type which uses a gauge to show how much the handle is bending while you are torquing the bolt. The clicking type is much better.

vstech · #3 08-11-2008, 12:59 PM

there is also a digital type... and one with a built in degree wheel... for setting stretch bolts. you can also buy a degree wheel attachment for any ratchet.
http://en.wikipedia.org/wiki/Torque_wrench

Jeremy5848 · #4 08-11-2008, 01:09 PM

The problem with the "click-stop" torque wrenches is that they are "digital." You have no visibility as to when you're getting close and none as to how much over-torque you're putting on a fastener (that you're trying to break loose).

The torque wrenches with a speedo-like dial are accurate and expensive. I have an I-beam cheapie, bought many years ago, that does what I need it to. It won't allow you to set a torque to the nearest foot-pound but most automotive applications don't require that much resolution.

I suspect that most of use the "Armstrong method" for most things anyway.

Jeremy

tangofox007 · #5 08-11-2008, 01:20 PM

Quote:

Originally Posted by Jeremy5848

The problem with the "click-stop" torque wrenches is that they are "digital." You have no visibility as to when you're getting close and none as to how much over-torque you're putting on a fastener (that you're trying to break loose).

The wisdom of using a torque wrench as a breaker bar totally escapes me.

wbrian63 · #6 08-11-2008, 01:33 PM

I have two - one 3/8" the other 1/2".

The "resolution" of the 3/8" is much lower than the 1/2" - there are many torque values for fasteners on my '93 MB that are too low for the 1/2" to handle.

Regardless, with click-type wrenches, I've been told to ALWAYS set them back to zero before storing for extended periods. As I understand it, the torque limit is set via some sort of spring inside the wrench. Twisting the handle tightens the spring. Leaving the spring in tension over long periods allows for stretch, which affects the accuracy of the wrench.

TheDon · #7 08-11-2008, 01:40 PM

Quote:

Originally Posted by tangofox007

The wisdom of using a torque wrench as a breaker bar totally escapes me.

sometimes certain situations call for a torque wrench in aiding in the removal.

Say you have a bolt that has been corroded due to mixed metals and welded it self to the threads. You know the breaking torque or what have you of said bolt. Using the torque wrench to get close to, but not the exact value you try to break it free. If try and do it with a breaker bar, you have no way of gauging the torque you are putting on the bolt.

Hatterasguy · #8 08-11-2008, 02:06 PM

Snap On are probably some of the best, at least that I have used. But Craftsman are pretty good.

I got a real cheap POS one from ebay for $20 to tighten my wheels.

You really need two, a 1/2in and 3/8. If your only buying one you can get away with a 3/8 for most engine work.

I'd go with Craftsman.

vstech · #9 08-11-2008, 02:32 PM

I would say you need three.
the 1/2 inch and the 3/8 inch are important, but you also need one calibrated in inch pounds.
you don't wanna see what a trans pan bolt looks like after you set the wrench to 70foot pounds instead of inch pounds...

bgkast · #10 08-11-2008, 02:36 PM

I had one from harbor freight, but it exploded...

compress ignite · #11 08-11-2008, 02:48 PM

If you opt for the "Click" type:

1.They are most accurate at the middle part of the measurement range.
2.You must "Exercise" them before each use(set it to two or three successively
greater measurements and click it on the lug nuts).

BGKAST,

Using one of those fine quality crafted Chinese Slave Labor Produced tools
at anything over 400ft/lbs occasionally causes installation difficulties.
(I also have one ,but only for lug nut installation.And I'll admit to checking it
against the old flexible Beam one.)

wbrian63 · #12 08-11-2008, 02:54 PM

Quote:

I would say you need three.
the 1/2 inch and the 3/8 inch are important, but you also need one calibrated in inch pounds.

My 3/8" drive is calibrated in inch-pounds. I bought it when I needed a torque measurement that was below the lowest settings available on my 1/2" drive unit.

Both are Craftsman, but 10+ years old, if that matters.

winmutt · #13 08-11-2008, 03:50 PM

Any of the click styles are pretty much of the same quality, don't spend big on them. If you want to spend big then get the digital.

bgkast · #14 08-11-2008, 04:18 PM

Quote:

Originally Posted by compress ignite

BGKAST,

Using one of those fine quality crafted Chinese Slave Labor Produced tools
at anything over 400ft/lbs occasionally causes installation difficulties.
(I also have one ,but only for lug nut installation.And I'll admit to checking it
against the old flexible Beam one.)

Using one for a breaker bar for lug nut removal occasionally causes explosive problems.

I replaced it with the craftsman I mentioned.

tyl604 · #15 08-11-2008, 06:13 PM

Thanks guys. Here is what I found. The $15 about 15 inch, 3/8' clicker has increments of inch pounds and metric (forget what it is). The $39 about 18 inch, 1/2' clicker is in foot pounds and goes from 10 foot pounds to maybe 400 foot pounds(do not quite remember) and also has NM. When I tried to set and lock the smaller wrench, it would not seem to lock very well and I could still move the handle. The larger had a slip up, slip down lock and worked. However not sure the larger one will handle the below 10 foot pound needs.

I am more familiar with the speedo type shown by one of the responder's picture. Outlet of course did not have any of these.

Thinking about going to Craftsman or maybe NAPA to look. Not sure I want to buy an unbranded torque wrench from an outlet store six hours away from Atlanta.

Thanks again for the output. By the way is 120 inch pounds equal to 10 foot pounds the proper conversion? Sounds logical.