What Is a Monkey Wrench?
A monkey wrench is a tool that can be used to loosen and tighten bolts and nuts of various sizes with a single wrench.
The worm gear on the end of the wrench moves the jaw of the wrench to adjust its size.
Normally, you need to carry several wrenches to match the size of the bolt or nut. However, if you have a monkey wrench, you can use only one.
Uses of Monkey Wrenches
Monkey wrenches are used to loosen and tighten bolts and nuts.
It is especially useful when loosening and tightening bolts and nuts of various sizes at a time at work sites. With a conventional wrench, it is necessary to change tools for each size of bolt or nut, which may take a lot of time and effort to change tools or risk falling off the wrench.
The basic usage is the same as that of a wrench and is very simple.
First, apply the monkey wrench to the bolt or nut to be loosened or tightened, and use the worm gear to move the width of the wrench tip to adjust the size of the bolt or nut to be clamped. After the size is adjusted, the wrench is rotated and torque is applied to loosen or tighten the bolt or nut.
Since the tip of the monkey wrench is movable, there is a misalignment in the meshing part of the worm gears, and torque is easily lost during loosening and tightening operations. Therefore, it may not be suitable for parts that need to be tightened or loosened, such as bolts that have become too hard due to rust or screw lock.
Principle of Monkey Wrenches
The principle of monkey wrenches is to change the size of the wrench tip by the action of worm gear.
The worm gear is generally composed of a cylindrical gear (worm) and a bevel gear (worm wheel), and rotating the worm rotates the worm wheel with which it is meshed to change its position. While the advantage is that the size can be easily varied by adjusting the worm gear, the wrench tip deteriorates quickly because the wrench tip is moved by the combination of two gears.
How to Select Monkey Wrenches
When selecting monkey wrenches, there are three things to keep in mind:
1. Opening Size
The most important factor in selecting monkey wrenches is the opening size. Although it has a worm gear and is movable, the range of opening is fixed. You need to choose a monkey wrench that opens larger than the size of the bolt or nut you want to loosen or tighten. However, be careful not to make the opening size too large, as it will not be able to be clamped firmly
2. Check if the Worm Gear Is Not Rattling
Basically, a worm gear is attached to the wrench, but if the worm gear loosens while loosening/tightening the bolt, the wrench will not be able to be clamped firmly.
3. Size
The surrounding environment when loosening and tightening bolts and nuts should also be considered. If you are in a small space, a thin type with a short handle will be easier to work in a crevice. If there is a large space, a longer and thicker handle will loosen/tighten with less force and be more stable.