How to Connect a Roller Chain

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Step 1. Bring the two ends of the chain together

There are two main situations that determine the specifics of this step:

1. extending an existing chain.
2. creating a loop for a drive system or conveyor.

1. Extending an Existing Chain

When connecting sections of a roller chain to extend its length, Step 1 is straightforward. You will simply lay both chain sections flat on a workbench or floor and bring them together to meet.

However, when it comes to connecting a roller chain into an endless loop on a drive there are two possible scenarios.

2. Creating a Loop for a Drive System or Conveyor

When creating a loop for a drive system or conveyor, things get a bit more nuanced depending on the sprocket accessibility.

2.1. Connecting the Chain on a Sprocket

This scenario involves connecting the chain on one of the sprockets of a drive by hand. The minimum requirement for this procedure is free access to one of the sprockets. Wind both ends of the chain around it, making rollers interlock with the sprocket teeth. The free ends should meet on the sprocket and should be separated by only one sprocket tooth. Hold the ends in place on the sprocket and proceed to Step 2 where you will be inserting a master link.

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2.2. Joining the Chain with a Chain Puller

When the setup doesn't allow access to the sprocket, or you are dealing with heavier chains, joining the chain between the sprockets might be necessary. This is where a chain puller comes in useful. A chain puller is a tool specifically designed to help draw the chain ends together for easier connection.

Chain connecting puller tools come in different sizes, therefore you need to select a puller specifically designed for your chain size. Ensure it's from a reputable supplier and made with high-quality, high-strength tool steel with precision-manufactured components. Using a low-quality puller can cause injury and equipment damage.

Here's how to use a chain puller to connect a roller chain:

1. When installing the chain, ensure its appropriate direction of travel and position it on the drive. The free ends of the chain should meet in the center between the two sprockets.
2. Position one jaw (gripping end) of the puller between the rollers of one end of the chain and another gripping end between the rollers of the opposite end you want to connect.
3. Tighten the chain puller's screw or mechanism to draw the two ends of the chain together.
4. Continue tightening to pull the ends close enough to where you can insert a connecting link.
5. Proceed to Step 2

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Step 2: Slide the Pins of The Connecting Link Into the End Links

Insert the pins of the master link through the bushings of the two roller links at each end of the chain. Before doing that, make sure the master link is graded for your type of setup and expected workloads. For cotter pin type construction, a regular pin link can be used as a substitute for the connecting link. Checkout this article on How To Install Chain Connecting Link for more detail.

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Step 3: Slide the Outer plate on the Pins

Install the free connecting link cover plate by sliding it onto the ends of the connecting pins. The described process applies to slip-fit chain links. Ensure you use an appropriate pressing tool for a press-fit link (for example, when using a regular cottered chain roller link instead of a master link to connect the chain ends).

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Step 4: Fasten the Plate with the spring clip or Cotters

Fasten the plate using the spring clip or cotter pin fasteners depending on the type of your master link.

4.1. Spring Clip Master Link

Snap a spring clip on the pins of the master link. Ensure that the closed end of the clip faces the direction of chain travel.

4.2. Split Leg Cotter Pin (s):

1. Insert the cotter pin(s):
• For two-pin installation, insert the cotters in the pin holes from the sides of the link towards its center.
• For single-pin installation insert the cotter through the holes of both pins from the direction of chain travel so that the sharp ends face away from it.
2. Flex the legs of the cotters apart. The angle between the cotters shouldn’t exceed 90 degrees. Excessive spreading may lead to premature breakage.

4.3. Shepherd's Crook Cotter Pin:

Orient the hooked end towards the chain travel direction. Push the pin through both pre-drilled holes. Snap the hook over the top of the connecting link pin to secure the cover plate. Crimp the middle section of the shepherd's crook for a tight fit (avoid damaging the pin).

4.5. Z Style Cotter Pin:

Insert the pin through the holes until the pre-bent side touches the chain link pin. Bend the opposite end away from the pre-bent side using pliers, but avoid creating an S-shape or wrapping it around completely.

For installation images and more information, refer to this guide “How To Install Chain Connecting Link”.

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Step 5. Ensure Tight Fastening

When the spring clip or cotters are in place, tap or push the pins of the connecting link inside. The goal is to make the fasteners sit tightly against the outer plate. It allows for better interlocking of the chain with the sprocket, promotes better lubricant penetration and extends the lifespan of the fasteners.

Finally, if a chain puller tool was used to pull the ends of the link together, release the tension on the chain puller and remove it from the chain.

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Offset Link Use Precaution

The steps above apply to a normal setup where an even number of links is used. Although not particularly common, a setup may require an odd number of links to be connected in the loop. For that purpose, you can use a special type of link called an "offset link." The downside of offset links is that they are not as strong as regular chain links. Because of that, it's best to avoid them if possible by using an idler sprocket or adjusting the distance between the shafts to take up the slack.

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