Question for mechanics, physicists about leveraging 2 wrenches for more power

[Dennis S]

If the main wrench was as long as both wrenches together, would it have the same strength or does the 2nd wrench somehow multiply or increase the leverage by being separate?

[Ken Sp.]

Should be the same force, overall, but there is a big stress point where they meet.

[btfc]

One could also use a cheater bar in such a situation.



http://en.wikipedia.org/wiki/Cheater_bar

[Dennis S]

When I look at it, it seems like there is leverage on the main wrench by the 2nd wrench on top of the leverage of the main wrench on the nut. Like multiplication or amplification of force.

[btfc]

Just the mechanical advantage of a longer lever.

[Carm]

What Ken said, but I would use a cheater bar or rubber mallet.

[Ted King]

This is a simplification, but essentially the mechanical advantage is the ratio of the length of the effort to the length of the resistance arm. By adding the second wrench the way shown in the image in the OP, what is being done is increasing the length of the effort arm. A larger wrench the same length as the two wrenches together would have the same mechanical advantage because it would be the same length effort arm. As other posters have said, if you had a steel pipe with an inside diameter bigger than the width of the open end of the wrench that you could slide over that open end, that would make a "cheater bar" that, depending on the length of the steel pipe could increase the mechanical advantage much more than the second wrench (which looks like it has the potential of slipping and causing a nasty scrape or worse).

Heating the nut with a torch often works wonders to loosen rusted nuts/bolts (just make sure you aren't also heating something like a brake line full of brake fluid). You could also try some kind of liquid penetrant WD-40 (probably not that effective) or Liquid Wrench (okay stuff but there is much better) or something more industrial "strength" like Blaster PB Penetrant.

[DRR]

You should probably soak that sucker in penetrating oil for a few hours before you even bother attempting.

[olnacl]

Time to heat the nut.



Voila! Success on the first bolt... the heat, the Liquid Wrench, the four foot cheater pipe did the trick.

[cbelt3]

Yep--- go for the six foot pipe. If the stud breaks, it probably needed replacing anyway ! :biggrin:

(blew through three tire studs that way on an Oldsmobile once.)