Lawrence08648

You need a click torque wrench rather than the bar. When accuracy matters, I find the bar isn't accurate on small parts where it matters. An expensive torque wrench for occasional use such as Harbor Freight will be fine. HF isn't known for quality tools.

I agree with San Rensho. You need the smaller torque wrench for the small parts on a bike and the carbon parts. You can get buy with a 3/8 or 1/2 drive ratchet for everything else. When you consider the price of Harbor Freight tools, it might be a nice idea to buy the 1/4" and the 3/8" wrenches.

One thing that hasn't been addressed, you can't put on a 1/4" socket adapter on the 3/8" torque wrench. When you do this, you change the final torque. You also can't use an extension for the socket without calculating the torque that has been lost.

Camilo

I understand the extension since torque is force applied at a certain distance from the fastener.

I don't understand the point you're making about the socket adapter. The center of the socket doesn't change with the adapter. Therefore the distance from the fastener to the point the force is applied doesn't change.

amorrow

Thanks for the replies. Let me restate my question.

Why does the wrench with the smaller pound rating (0-80) have a larger socket (3/8)?

For the smaller bits, I know I want the smaller pound rating, but I would have assumed that would mean the 1/4".

amorrow

This is what I mean. The smaller ratchet is 1/4", but the smaller pound capacity is 0-80. I know I want the 0-80 for my purposes, but this seems strange.

Al1943

I use a 1/4" drive beam wrench, Park TW 1, and a 1/2" beam wrench, Craftsman, it's handy for bottom brackets, cassettes, and aluminum alloy car wheels and manifolds. I've had the Craftsman 38 years.

Al

Grand Bois

Really? How is the torque lost?

twobikes

The extension has some natural twist and it absorbs some of the torque force so that you get a false reading.

amorrow

Can someone explain to me why the wrench with the smaller ratchet (1/4) has the largest poundage rating (0-80)?

Grand Bois

And how do you calculate the amount of torque that's been lost? How much do you think an extension or adapter twists when you are torquing a bolt to 35 ft lbs?

What is the source of this information? Are you making it up as you go along?

Perhaps you are thinking of the correction that must be calculated when using a crow's foot with a torque wrench, something I can't imagine ever doing while working on a bicycle.

Camilo

Amorrow, this was explained a couple of times after your first question. For example:

The measurement isn't "pounds" like you keep saying. It is either "FOOT POUNDS" or "INCH POUNDS". One FOOT POUND = 12 INCH POUNDS; one INCH POUND = 1/12 FOOT POUND.

You have to pay attention to the units specified for each wrench. The 1/4 inch wrench is stated in INCH POUNDS. The 3/8 inch wrench is stated in FOOT POUNDS.

Therefore, the 1/4 inch drive has a smaller maximum torque capacity:

1/4 inch: 200 INCH POUNDS maximum = 17 (200 / 12) FOOT POUNDS
3/8 inch 80 FOOT POUNDS maximum = 960 (80X12) INCH POUNDS

Does that make sense?

tippy

Sorry ... not enough information.

Pounds of what? Inches, Feet, Yards ... what?

Torque = length * force.

You keep providing the force but haven't considered length. Without length in the mix, you have nothing.

80 pounds or 10 pounds what is the higher torque??? Beats me. Those aren't torque values ... those are weights.

80 INCH-pounds or 10 FOOT-pounds, what is the higher torque? The bigger number?
Don't know. You have apples and oranges (INCH-pound vs FOOT-pound - not the same animal).
Convert to the same unit of measure FOOT to INCHES = Feet * 12)

80 INCH-pounds or 120 INCH-pounds (foot*12 or 10 * 12 = 120).

But wait ... I thought you said 80 pounds was the higher poundage rating???

It's not if you compare apples to apples ...

Grand Bois

One foot pound of torque equals 12 inch pounds of torque. What's so hard to understand?

Upassdme

That craftsman beam - type torque wrench will do anyone right for a good long time. You can also get a 3/8" beam or dial type inch pound torque wrench. Not to mention that beam type torque wrenches tend to be more accurate than the click type or even the dial types, they're a tad harder to read though. Unless you're a professional (any repairing anything) the snap-on line will be far over what you would ever dream of spending, the quality and accuracy is second to none though. I would honestly avoid loaner tools since you have no idea of what the guy that used it before you did with it ("everything's a hammer" and "hold my beer - watch this" come to mind).

twobikes

53.2% of all statistics are made up!
I do not have a source, but was simply trying to give a cogent explanation to why adding extensions would alter the actual torque, as mentioned by others.

A crow's foot would also change the functional distance involved in the basic equation of force over distance, and would thereby alter the actual torque a bit. 35 ft. lbs. is not a huge amount of torque. Torque charts also usually allow some latitude. While you may be aiming for 35 ft. lbs., the specs. probably indicate something like 35 - 40 ft. lbs. as a range of acceptable torque.

Upassdme

Formula for torque loss through an extension or crow's foot (really neat website for mathletes and physics people too if you're interested) : https://www.engineersedge.com/manufac...e_wrench_2.htm



Rule of thumb is about 1 ftlb per inch of extension.

Grand Bois

That's for a crow's foot, not for a socket adapter or extension.

The fact is, Lawrence08648's statement about using an adapter or extension is completely untrue and the fact that twobikes bought into it proves that he doesn't know what he's talking about either.

Upassdme

There are alot of torque wrenches that are calibrated in inch pounds that use a 3/8" drive socket. The most commonly owned and manufacturered socket drive size is 3/8". It actually works to your advantage because you don't have to have 3 or 4 different sets of sockets to do something with.

Upassdme

First sentence in the first paragraph on that link:

"The following is the calculation that one would use to determine the actual torque applied when using an extension or crow foot."

It's for both, an extension and a crow's foot.

Grand Bois

I calibrated torque wrenches when I was in the army. The click type need to be recalibrated the most often. The beam and dial type were the most reliable. Digital wrenches weren't invented yet, it was 40 years ago.

Grand Bois

Do you understand what a socket extension is? It extends the length of a socket. It has no effect on torque values.

A 3/8" to 1/4" drive adapter:



A 6" extension:

Upassdme

I work in vehicle service, and have for 15 years. Over that 15 years, I've accumulated somewhere in the neighborhood of $75,000 in tools. I have enough that I have "work" tools (typically high grade stuff) and "home" tools. Since I just went through and cleaned and took inventory on everything today, I have 22 extensions ranging from 1/2" long and 36" long. I've probably worn out more tools than the average person will ever own.

There is torque lost through the extension due to the tensile strength of the material used to make the extension and the amount of force applied to the handle of the tool. Not all extensions are made of the same material, and most that are generally purchased are of an alloy that is significanlty weaker than higher priced extensions. The property of the metal that they're made with prevents them from breaking under severe use. Metal bends and twists when there is force applied to it. The same thing that prevents them from breaking, prevents them from delivering the exact torque that you are trying to get. The torque that is lost is pretty minimal though unless you're using a 12"+ extension.

The catch here is that since most fasteners are torqued in a torque range and on a bike I can't for the life of me see anyone needing to be more than 3" from what they're torquing or taking off, the loss is so minimal and negated by the range, there's no real need to worry about it. Everything has a tolerance because nothing is perfect and there are variations in everything.

I'm really not flaming you and I hope you don't think I am, I do have pretty extensive experience with this though. I'm really only trying to pass along 15 years worth of experience and post high school vocational education to those that don't have it that can benefit from it. I guess I should have qualified my experience in a prior posting, I apologize for having not.

Grand Bois

I'm impressed.

twobikes

Are you really impressed? If so, does that mean I now do know what I am talking about? Or, are you being sarcastic?

amorrow

Yes, now it does. I was distracted by the discussion of how much torque is lost in extensions. Thank you.

amorrow

Yes, now it does. I was distracted by the discussion of how much torque is lost in extensions. Thank you.