jhammons01

There you have the obvious difference between a person who knows what they're talking about, and someone who doesn't. In the future, if you don't know, don't speak.[/QUOTE]

Scath,

You have given a lot of good advice to me and I appreciate it. I used to be a Maintenence Mechanic for a large mill in Texas, untill I graduated. everything we used was large size like this. I have a degree in physics If I had a fulcrum large enough I could move the earth. You speak of a "moment" Let me ask you something. Are you just going to hang there on your cheater bar??? What if you moved your weight just a little. What if your weight were moving downward with the use of gravity......say terminating on the end of a cheater bar. Would not weight x speed = velocity or in your terms a "moment" If you were 200lbs would your velocity at say 10 miles per hour be pretty great. Now add the length of the bar to the equation. what kind of figures are coming up with.

Your "impact" wrench is the same as a person hitting a wrench handle with a hammer. The wrench is inside the impact, it uses great force created with the use of air to "hit"....... the same as person with a wrench and a 4 lbs mallot. OR the same as a person with a cheater bar. The larger the cheater bar the less velocity needed. The hit or "moment" is what is the crux fo the entire process. Your impact hits very violently with a small stroke using little weight but moving very fast to create the "moment" A wrench with a hammer can be used in the same fashion. Your hammer has to get heavier or move faster to create the same amount of velocity. What if we increased the weight of the hammer exponentially? Say from a 4lbs hammer to 200lbs. Would we have to hit with the same force??? no not near the same force. Would we create the same velocity?? Yes

To prove the point of using the velocity factor, how many fo you have had to use a four way to take off a lugnut??? If you just leaned against the four way nothing would happen. Now put your foot on it, kinda jump and with your other foot and come down on the four way. The lug bolt comes loose with a crack. That was a "moment" I am not an engineer so I would have to look up how to calculate it but I can garantee it was a moment.

I do have to agree with you on the size of the bolt being thin. One should have a socket that fits snuggly.

vicious525E

i just got my 'flywheel stopper' from racing beat today, its something like thirty bux and will worth it.

MARTIN

Its worth it, if you dont have an impact gun....

bigdongsr94

3 foot bar on a 1/2 drive ratchet on pulley bolt with a 12in cresent stuck between the flywheel and the rear hoist point, then to break the rear bolt on the flywheel it was the same process but with a bigger breaker

Steel

the actual rapid violent strikes of the hammer in an impact wrench does a big part in removing tight bolts and nuts. It breaks the bond between the two parts and jiggles the molecules around. Same deal with using an air hammer on a stuck brake disk.

Do they make torque multipliers designed for impact tool use? Becasue that would make my 1/2" IR a lot more useful in this kinda thing.

Then again i can always ask my buddy with the big motherfarkin 1" drive impact to take it off for me.

RotaryEvolution

iTrader: (30)

i have seen a lot more broken cheater bars on this forum that pictures of broken impact guns. i will stick with my argument, you are correct in your reasoning but in truth it all comes down to which works better and i have had nothing but success with my impact guns but i have broken many a breaker bar/ratchet/extension while using leverage rather than the blow from an impact gun.

dgeesaman

iTrader: (7)

I'm not Sean, but I read his discussion and he's spot on.

Impact and bouncing your weight are still two different things. First, your question about how much extra moment you can generate when bouncing your weight on the bar - it's around a factor of 2. For example, if I was designing a diving board, I'd design it for around 2x the person's weight at the end of the board. For additional motion like stomping your foot (as you mention below) maybe 4x.

The word moment means torque - completely interchangeable. I think you have some confusion there.

The reason an impact wrench has an advantage is because it simulates hitting your breaker bar with a hammer - the shock (impulse, technically speaking) has a tendency to crack through corrosion between the threads. Stomping on a lug wrench is a so-so way to generate it - an impact wrench is like taking a very light and very stiff breaker bar and smashing it repeatedly with a very heavy mallet. That's the kind of shock energy it's putting on the nut. The reason why you can't do it the manual way when you get into big torques is the bar gets flexible and our body weight is insufficient to do it safely. Unless you're a nose tackle and have lots of space to jump around on it.

The guys at work often deal with BIG nuts (2" - 5" thread) and they use.... impact wrenches and torque multipliers. A few thousand ft-lb of torque. There is no substitute.

vicious525E

or the money to afford a impact big enough to take off the flywheel bolt.
because, as we all know, that is torqued to 350 flbs and is thread locked, not to mention years of heat..

scathcart

Do you actually want me to calculate this? I can if you still want me to, but read the following first.
(BTW... 10 miles per hour? do you have any idea how much it will hurt to be hit with a rigid biece of bar travelling 10 mph? This would be identical to someone swinging a bat and hitting you at 10 mph)

1. You can fall downwards onto the bar, and then strike the bar... basically, you are using your inertial velocity to create a larger moment to the bar... Now, striking the bar all of a sudden will cause the bar to hit you as hard as you hit it: for every action force there is an equal and opposite reaction force. So, if you really wanna jump down on the bar, its really going to "jump" back up at you, just as hard as you hit it. Now, this impact can also jar the socket loose, or break the cheater bar, risking injury.
There is no such thing as "justifiable risk" when it comes to car work.

2. You can support your full weight on the bar, and kind of bounce on the bar... now, since you having no initial velocity, you will be creating velocity through movement of the bar (to have velocity, you must move). This deflection must come from the bar... you are bending the bar to create velocity. This flexing period is almost always when breaker bars let go.
Again, not safe.

Basically, what you are trying to do is apply an impact to non-impact steel... big no-no.


The correct way of using a breaker bar is to press the socket against whatever fastener you are trying to undo, and then apply an evenforce to the end of the breaker bar, and then linearly increase the applied force until you can no longer apply any more than your body mass. You should never bounce, and never put a longer piece of pipe on the end. They make 8 foot breaker bars with a 1" drive: if you need more torque than that, you need to use an impact gun.


This is all bejond the point, anyway.
1. You said impact guns will break if you hold the trigger. This is not true.
2. Impact guns will always be more effective, faster, smaller, and more compact than cheater bars. You can NOT develop 8000 ft-lbs of torque safely with ANY cheater bars. Its very simple with a small impact unit.

Breaker bars are cheap and effective, yes, but they are not as effective as impact guns.