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Recently I tried to get extra torque out of a spanner when unscrewing a bicycle pedal by lengthening the spanner with a piece of pipe and the spanner just broke apart.

I realize that this was something to expect - no spanner will tolerate infinite stress, but maybe I could have done it better so that I got more torque without actually breaking the spanner.

Are there any tips to how to get more torque out of a spanner without having the spanner broken?

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Quick check: Were you turning the pedal the correct direction? On a bike, one pedal will be threaded opposite the usual direction. The left pedal turns clockwise to loosen, not anti-clockwise. Further tightening what you meant to loosen would explain not being able to unscrew the pedal no matter how hard you tried. –  Jeremy W. Sherman Jul 30 '12 at 17:57
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Short answer: buy higher quality tools. –  Alex Feinman Jul 30 '12 at 19:07
    
@Jeremy W. Sherman: That's another question, I asked that on Bicycles SE - bicycles.stackexchange.com/q/10549/628 and here I just wanted to know how to get the maximum torque assuming the direction is right. –  sharptooth Jul 31 '12 at 8:05
    
Spanner was faulty! I would have thought the bicycle pedal would have stripped its thread if turned the wrong way before the spanner shattering. If you used the pipe method make sure the spanner is SIDE ways- keeping it flat will bend it. I have never seen a shattered spanner. Can you post a photo please! –  ppumkin Jul 31 '12 at 12:40
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8 Answers 8

The first thing I would think about is not how I get more torque out of a spanner, but why I need to. Your average spanner (wrench) produces a lot of torque, and adding more in some cases is likely to break whatever it is you are trying to fix, rounding off the nut, or breaking the tool (as you experienced). It's far better to figure out why something is stuck and trying to remedy that by using some penetrating fluid like wd40 or the like, or maybe some gentle tapping with a mallet in a strategic place.

To answer your original question a piece of pipe is my standard solution for those extra torque situations just as you used, but it helps to have good quality steel tools and not cast chromium alloys as the last tend to shatter.

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I will virtually NEVER, EVER need to artificially lengthen a tool to get sufficient torque on a nut or bolt. So why not?

I have more than a single wrench. (Sorry, substitute "spanner" for "wrench".) Multiple tools to fit multiple problems. Large, unfriendly nuts and bolts, that take larger amounts of torque to turn are solved using larger tools, able to apply the torque needed. When needed I use a penetrating oil, or a bit of heat carefully applied in the proper place can help too.

Next, I tend to avoid an open end wrench whenever a socket wrench or a closed end wrench will work. A closed end wrench will not slip off the bolt, so there is less of a problem. As well, an open end wrench can tend to round off the nut/bolt one is turning, so it is a poor choice. This is why a 6 sided socket is my preferred choice for most problems. Since you can buy closed end wrenches that ratchet, they are also much faster to use than a simple adjustable wrench. (Avoid those gimmicky open end wrenches that claim to fit ANY size nut or bolt. They never work as well as claimed, and risk rounding off the corners when you work them too hard.)

On the MOST difficult nuts/bolts to turn, I'll pull out a breaker bar. This is a moderately long, strong bar for sockets, and I use a set of sockets designed for an impact wrench. They are properly hardened sockets, designed to take extra torque and abuse.

My point is, have more than one tool to fit the problem at hand, not one small tool and a huge piece of pipe. Expand your set of tools to solve the problems you find. This is well worth the investment. You don't need 100 different tools, just a few carefully chosen ones, a set gradually expanded as they become necessary. Otherwise, expect a lifetime of nuts and bolts with ruined heads and broken tools.

Think of it like this: why buy the same tool many times after breaking it over and over again, instead of buying several tools that will last your lifetime? This brings up one other point, to buy good quality tools. I expect to never need to replace most of the wrenches in my toolbox. So avoid buying a set of cheap tools. Go for quality.

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Bicycle pedals are generally removed with specialized wrenches that are thin in cross section, but are hardened to handle the torque, e.g.:

pedal wrench

The one illustrated is a heavier duty and longer than the cheaper kind (even from the same company). As is discussed by Jeremy Sherman in a comment, it is essential that you know whether it is lefty or righty.

As has also been suggested, a lubricant may help, as may a moderate tapping on the handle with a mallet/hammer (careful!) to break the hold.

If you need more leverage, something is wrong (significant rust, previous overtorque, etc.)

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Here in the USA, we have a major retailer with a popular line of hand-tools with a lifetime warranty that is usually honored without question or hassle. The tool breaks for any reason, bring it back and get a replacement.

One giant exception to this are wrenches (spanners) that were broken when a pipe was used to add extra leverage. The clerks in the tool section can spot the tell-tale marks from across the room. No replacement tool for you!

It's dangerous and it causes more trouble than it's worth.

You need a breaker bar and a socket set. The breaker bar is a solid steel bar, a third of a meter or longer, with a socket fitting on one end... it's like an extra-long ratchet without the ratchet. It's designed to handle this sort of work safely.

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Or you can buy Snap-On, in which case they'll replace them even if you break em on purpose :) –  Eric Petroelje Jul 30 '12 at 20:50
    
a breaker bar and socket set isn't always an appropriate replacement for an open-end wrench. The OP was working on a bicycle pedal, where a socket is not an option. –  mac Aug 1 '12 at 16:45
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Very good answers by eveybody here. Especially WoodChips answer because he is absolutely right in saying that each problem has its own set of tools. May I add time and brain power should be the most you need to solve those problem with out due force.

BUT.. if you cannot be bothered and just need something doing. .THen the pipe and wrennch method is the big boy of getting stuff unstuck - but also causes shattering, thread stripping, pipe bending and some times bodily harm and mega frustration.

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Try and get the pipe to cover as much as the handle as possible and ensure the front end is well connected as is the rear end of the handle inside the pipe. These are key points and greatly help disperse your power into torque through out the entire handle of the wrench.

  • Sometimes it feels like you have to jump on the pipe.. refrain from doing that. Mostly painful outcomes for the person trying it and hilarious sight for any body standing around watching you work.
    • As mentioned before- make sure you are unscrewing in the correct direction. Some threads are countered to prevent natural unscrewing effect.
    • Apply some MD-50 lubrication and wait 10-30minutes between tries. Don be shy. spray it on there.
    • A gem in DIY techniques is sometimes to slightly.. very very slightly! tighten the screw in the attempt to loosen it, THEN then un tighten it. doing a see saw effect over and over as the screw gradually un fuses.. spraying some MD50 on there all the time.
    • Applying force in burst and not continues. IN other words don't hang/stand on the pipe just pull/push it let go, pull/push it let go, over and over applying more bodily power on each pull/push and see if it starts to give..

I hope this helps you.. :-)

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For stuck bicycle pedals in particular:

  1. As has been mentioned, make sure you're turning in the correct direction. One of the pedals (the left side) has a reverse thread.

  2. Use a penetrating lubricant. PB Blaster is a good example.

  3. I'd use impact before I used leverage: Holding firm pressure on the wrench and repeatedly striking the end of it with a heavy object (obviously in the direction you wish to turn it) produces a momentary shock of torque that can serve to work it loose bit by bit. Rust in particular is brittle, so repeated shocks seem break up the internal binds better than one massive/continuous force.

    For an example of the effectiveness of this technique, search youtube for "how to remove a cordless drill chuck"

  4. For the above reason, if I did have to resort to a "cheater" (length of pipe) I'd only do so after I had done some pounding with the hammer first.

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I use the pipe trick once in a while, and have never broken a good wrench. (snap-on, armstrong, ...) but it is likely to slip on the bolt. For pedals i use a pipe wrench, and again, if it is a good one (Rigid tool) you can extend with a pipe for leverage. This will mar the fastener a bit so if that matters buy a pedal wrench.

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Hold it at the end. (the further you are from the pivot point [nut in this case] the more torque it will produce)

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Yes that makes sense! But the pipe cannot be situated right at the end. The pivot point must be from the start(start of pipe and wrench- and the end of the pipe- some short distance inside the pipe) Then the longer the pipe the greater the torque. This also insure even distribution of power throughout the entire wrench. –  ppumkin Jul 31 '12 at 12:42
    
an alternative - take it to a bike shop. –  Mark W Jul 31 '12 at 14:19
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Yes definitely - but that does not categorise under DIY ;) –  ppumkin Jul 31 '12 at 14:27
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