Another Question about Torque Wrenches

[Loscaldazar]

Ok, so I did a bit of searching already, and didn't quite get my answer. I recently purchased 2 Precision instruments split beam torque wrenches. I ended up getting flex ratchets, and later figured out they also make rigid and fixed ratchets.

Now, flex ratchets should still apply the correct torque (even if not straight up and down) because the torque applied at the fastener is still @90 degrees. It will just take more effort at the end of the torque wrench to click the split beam at the specified torque. Correct?

Then, what is the difference between a rigid and fixed type ratchet, and is it worth spending the extra money (about $40-50 more at the place I bought them from, still cheaper than most places) to get those type instead? I got the 3/8 for $95, and the 1/2 for $130.

Thank you!

 

[Steinmetz]

With reference to question 1, correct. As to question 2, I don't know.

 

[Rezeppa]

It all depends on the application. What are you torquing? What is the level of precision needed? Ridged is essentially fixed head and standard obviously is a ratcheting mechanism w/o the flex. I own click type torque wrenches. I don't like flex head because of the added work in calculating measurement. The problem is when you need to torque a fastener that a standard wrench can't get on that flex head becomes extremely valuable. I am not an expert on torque wrenches just trying to give you my basic understanding.

 

[CWP1616L]

The flex head 1/2 drive will be convenient for wheel lugs. You might not need the flex head for 3/8 drive.

 

[Loscaldazar]

It all depends on the application. What are you torquing? What is the level of precision needed? Ridged is essentially fixed head and standard obviously is a ratcheting mechanism w/o the flex. I own click type torque wrenches. I don't like flex head because of the added work in calculating measurement. The problem is when you need to torque a fastener that a standard wrench can't get on that flex head becomes extremely valuable. I am not an expert on torque wrenches just trying to give you my basic understanding.

PI (the maker of the torque wrenches) lists fixed and rigid as two different types of split beam wrench. You can order the 1/2 drive Split beam in flex, rigid, or fixed. So there must be some difference between rigid and fixed?

And you say that the angle of the handle does affects the torque, but the socket and head of the ratchet (which is the part that clicks to prevent over torquing) still are applying torque at 90 degree, even though the handle isn't? The amount of force applied at the handle would be more, but since the wrench measures torque at the fastener/ratchet head, then the angle of the handle shouldn't matter? Otherwise wouldn't the position of your hand also affect torque because it would be measuring force applied to the handle to click, not resistance of the fastener?

 

[KPAero]

I have a PI 1/2 torque wrench that I am guessing would be the ridged model. It's head can move, but is limited to a few degrees in either direction, so its not a true flex head. I like the feature.

 

[pipsters]

I did some unscientific tests on my torque wrenches. I found the PI wrench to be the one with the most variance in its reading, and some were way out of spec. A small flex will do almost nothing to the torque value, the torque wrench itself will cause it to be accurate or not.

If you are seriously concerned about accurate torque, you need to get a beam style torque wrench. In my experience they are the most accurate and most repeatable type out there.

 

[wafrederick]

I have seen the mistakes some do when using a torque wrench.One is jerk on them,get a false reading this way when jerking on a clicker type torque wrench.Once it clicks,stop.Using it to loosen nuts and bolts too,not made for this.I don't like the beam type,hard to read

 

[Charles (in GA)]

I have seen the mistakes some do when using a torque wrench.One is jerk on them,get a false reading this way when jerking on a clicker type torque wrench.Once it clicks,stop.Using it to loosen nuts and bolts too,not made for this.I don't like the beam type,hard to read

If you are not familiar with the split beam, it is nothing like a beam type torque wrench. It is a clicker type that uses an internal split beam.

As far as the question about the heads, the flex head has only 11° of flex and that is not enough to make any measurable difference in torque, you will never notice, just try to keep it as straight as possible but if you need to flex it, do so.

A non flex ratchet is like any other ratchet or torque wrench, and you do not want a fixed square drive. The tool room handed me one at work the other day, I guess all of the good ones were out for calibration. Anyhow, I ended up putting an inline ratchet on it to get the job done, as I didn't have much swing room.

Charles

 

[Treeman]

Then, what is the difference between a rigid and fixed type ratchet,

Thank you!

Absolutely no reason for buyer's remorse on your excellent choice. Your terminology is wrong above, compared to the PI web site. This is causing your confusion. http://www.torqwrench.com/tools/genPage.php?type=C&drive=3

There is no fixed type ratchet in their catalog.

Listed are:
Fixed Drive: There is no ratcheting mechanism (like a breaker bar).
Flex Ratchet: Ratchet head that swivels 11 degree.
Rigid Ratchet: Ratchet head that doesn't swivel.

The fixed drive is probably used most in a repetitive industrial situations where they want to reduce variables (flex head), are doing a simple tightening with easy access, and KISS (keep it simple)....less moving parts, error, etc..

The flex head can be used straight if and when you need that, but gives you the versatility to slightly angle it when needed. I love the flex in both sizes.

If still confused, we have a PI company member here that will straighten us out. I hope he addresses Pipster's claim also!

EDIT..AGAIN Looking at my link, I see their web page is in error also. In the left "refine search box" they list a fixed ratchet also. Come on PI, fix your web page! Looks like fixed ratchet = rigid ratchet.

 

[SMKS]

I have a PI 1/2 torque wrench that I am guessing would be the ridged model. It's head can move, but is limited to a few degrees in either direction, so its not a true flex head. I like the feature.

That actually is the flex head, I think.

The PI flex ratchets have really limited movement, like 15 degrees or something.

At one of my old jobs we had several of the PI made Snap-on torque wrenches. They were the flex models, but had really limited movement.

I assume it's so the flexing of the head doesn't affect the applied torque, or at least so it's only affected by a very small amount. But, I'm no engineer.


EDIT- I now see people posting above me also answered the question. So, lump me in with the others who say "that is the flex model and it's supposed to be that way."

I did some unscientific tests on my torque wrenches. I found the PI wrench to be the one with the most variance in its reading, and some were way out of spec. A small flex will do almost nothing to the torque value, the torque wrench itself will cause it to be accurate or not.

If you are seriously concerned about accurate torque, you need to get a beam style torque wrench. In my experience they are the most accurate and most repeatable type out there.

Well, to be fair, as you admit it was unscientific and used only a single example. Plus, the most it was ever off was by 5.25%, which was only one single pull out of all the pulls you did on that wrench. I should note, that's if I'm understanding your numbers correctly, which I may not be. That's still pretty darn close. So, I won't be condemning PI split beam wrenches based on that one example.

If I'm reading your numbers correctly from this thread, you did 5 pulls, and used the one that was the farthest out to calculate the error. The other 4 pulls were closer to accurate, so we can't rule out a fluke in that single pull (improper use of the wrench, pulling too far, etc.)

I don't know how PI calculates the 4% accuracy, but if we average out the numbers of your 5 pulls it comes to 39.86 on a setting of 40. That seems pretty accurate to me. Again, correct me if I'm wrong. I'm just trying to make some casual observations.

I'm not knocking you for doing the "test," it was very interesting to read and I appreciate that you took the time to do it. But as you note, it wasn't scientific.

 

[Loscaldazar]

The amount is rather small, did some calculations here after getting finding some length specs on the wrenches. For the 3/8 drive ratchet, when setting it to 75 FT-lbs, at a maximum deflection of 15 degrees, the torque is off by 3.5% (so around 72 FT-lbs, not accounting for calibration inaccuracies). That isn't a bunch, and I suppose my question become more academic rather than vital. The question is, does the flex handle even affect the torque that is applied to the fastener?

Let me lay out my reasoning/ramblings in hopefully a much more clear way.

The socket and head of the ratchet still stay at 90 degrees to the nut/bolt being tightened. They are still applying torque at a 90 degree angle ("100%" efficient).

The handle is at an angle to the actual ratchet mechanism.

Now, when does the internal device click when at an angle? When 75 Ft-lbs is applied to the handle, or when 75 FT-lbs is applied to the ratchet head.

If it clicks when 75 ft-lbs is applied to the handle when at an angle, then yes, then using the handle at an angle does affect actual applied torque to the fastener.

If it clicks when 75 ft-lbs is applied to the ratchet (which is at 90 degrees to the fastener), then angle of the handle does not matter. It would take more force (force, not torque) on the handle @15 degrees to click 75 ft-lbs than if the handle were @90 Degrees?

It just really seems that no one on the internet can give a straight answer to this question, and I would like to get to the bottom of it. I hate leaving unanswered questions!

 

[pipsters]

Well, to be fair, as you admit it was unscientific and used only a single example. Plus, the most it was ever off was by 5.25%, which was only one single pull out of all the pulls you did on that wrench. I should note, that's if I'm understanding your numbers correctly, which I may not be. That's still pretty darn close. So, I won't be condemning PI split beam wrenches based on that one example.

If I'm reading your numbers correctly from this thread, you did 5 pulls, and used the one that was the farthest out to calculate the error. The other 4 pulls were closer to accurate, so we can't rule out a fluke in that single pull (improper use of the wrench, pulling too far, etc.)

I don't know how PI calculates the 4% accuracy, but if we average out the numbers of your 5 pulls it comes to 39.86 on a setting of 40. That seems pretty accurate to me. Again, correct me if I'm wrong. I'm just trying to make some casual observations.

I'm not knocking you for doing the "test," it was very interesting to read and I appreciate that you took the time to do it. But as you note, it wasn't scientific.

I answered the questions in the other thread to keep it all together