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What Is a Ratchet?

Various nuts, bolts and screws.
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  • Written By: Mary McMahon
  • Edited By: O. Wallace
  • Last Modified Date: 20 March 2014
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A ratchet is a device which is designed to only allow movement in one direction. The design of a ratchet is extremely simple, and ratchets can be found in use in a wide variety of applications, from clocks to socket wrenches. Many hardware stores carry tools which utilize a ratchet mechanism, and ratchets can also be seen on surgical instruments and in a number of mechanical moving parts in everything from cars to watches.

The design of a ratchet includes a toothed wheel with teeth which are angled. A finger, known as a pawl, articulates with the teeth. The wheel can move freely in one direction, but the angles prevent the wheel's motion from reversing. A small amount of play in the reverse direction is allowed by the distance between the teeth in the wheel; precision ratchets are sometimes designed to limit this motion. Ratchets can be made from metal, plastic, wood, and composite materials, depending on what they are being used for and the cost of the item.

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One way in which a ratchet can be used is to lock something in place. The ratchet can be moved to the desired position, and then it will hold itself in place with friction. This technique is often used with surgical clamps. To open the clamp to remove it, the pawl is disengaged from the wheel. Another example of this kind of ratchet can be seen in some styles of blind, in which the pawl locks the blind in place at a desired height.

In tools such as socket wrenches, ratchets can be tremendously useful. In many tasks, it is not possible to complete a full revolution of a wrench. This would require the user to make a partial revolution, remove the wrench, move it back into position, make another partial revolution, and so forth. With a ratchet, the partial revolution can be completed before the pawl is disengaged to slide the handle of the wrench back into position without moving the bolt backwards. This makes tasks easier, and reduces the risk of stripping or damaging bolts.

The socket wrench is probably one of the most well known examples of this device. Socket wrenches usually come in a set, allowing people to fit different attachments into the head of the ratchet to deal with bolts of different sizes and shapes. Ratchet sets can include heads meant to match with a variety of bolts and screws, and they are a tremendously useful thing to keep around the workshop or tool box.

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Discuss this Article

Izzy78
Post 4

@TreeMan - I think I would consider something like a pair of handcuffs to have a ratcheting action, but probably wouldn't call it a ratchet.

When you are going to buy a ratchet set, is there anything in particular to look for? I had a set that I bought a while ago, but I have lost a few of the sockets over the years, and some of the sockets have started to rust.

I figure it is rusting because it was a cheap set and might have just had a silverish coating over iron. Are most higher end sets made of stainless steel?

jcraig
Post 3

@TreeMan - Actually, now that you bring it up, I do remember those infomercials. I actually bought one just to try it out. They sort of worked, but didn't have a lot of torque. Besides that, the handle came apart after a few weeks.

TreeMan
Post 2

Does a ratchet have to have a round piece that rotates? I was thinking about something like handcuffs or zip ties. They don't actually have a wheel, but they are made so that something can only move one direction through them.

Does anyone remember the infomercial ratchets that they were trying to sell in the early 2000s. Instead of it being the normal socket shape, there was a long tube or cord that went to the bolt and the handle was like a pair of pliers that you squeezed.

I never used one, but I always wondered how they worked. Obviously, they couldn't have been great, because they aren't still around.

cardsfan27
Post 1

I don't think I would be able to make it a month without my socket set. It is by far the handiest tool to have around. You can even get screw attachments for them, so you don't have to mess with screwdrivers unless you are in a narrow spot.

I never thought of all the other things I use every day that have some type of ratcheting mechanism.

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