Chain Tool

#25 Chain Tool Basics

This custom-designed tool, also commonly referred to as a "chain break" or "chain breaker", allows teams to easily break and re-assemble #25 Chain (REV-41-1365). The mandrel is used to push out the chain pin. If using Master Links (REV-41-1366), the pin can be completely removed, but the depth guide screw allows the option of partially pressing out the pin and then re-assembling without master links.

Kit Contents

The REV Robotics #25 Chain Tool (REV-41-1442) comes with the following:

  • 1 Chain tool block

  • 2 set screw mandrels

  • 1 depth guide screw

  • 1 cup point set screw

  • 1 3mm Allen Wrench

Before using the #25 Chain Tool for the first time, remove the thread pin screw and use WD-40 or compressed air to remove any shavings left in the tool from the manufacturing process. This will ensure the chain break works smoothly and efficiently breaks your chain. Reinstall the thread pin screw. Once this is complete the chain break is ready for use.

Manipulating Chain

Custom Length Chain

In almost all applications, chain links are connected to form a loop. While chain can sometimes be purchased in specific length loops, it is more common and economical to buy chain by the foot and make custom loop lengths to fit the application. It’s recommend to use a specialized tool, a chain breaker, to cut chain into desired lengths to prevent accidental damage.

Chain breakers do not actually cut the chain, instead they are used to press out the pins from an outer link. After the pins have been removed the chain can be separated leaving inner links on both ends of the break.

Chain Tools have two methods for resetting chain. Using Master Links and resetting the chain pin. Resetting the pin is results in a stronger chain than using a master link.

Roller chain is typically connected into a continuous loop. This can be done using a special tool to press the pins in and out of the desired outer link as described in the Custom Length Chain section, or if the chain is already the correct length a common roller chain accessory called a master link, or quick-release link, can be used to connect two ends of the chain.

Master links allow for easy chain assembly/disassembly without any special chain tools. Master links can typically be reused many times, but can become bent with multiple uses. At the point that master links become bent they should be discarded.

  1. Place the loose outer plate onto the two pins pressed into the other outer plate.

  2. Ensure the outer plate is inserted onto the pins far enough that the grooves on the pins are fully exposed past the outer plate.

  3. Align the widest gap near the middle of the clip with one of the pins.

  4. The gap in the clip should allow the clip to slip over the pin and sit flush against the outer plate and aligned with the groove in the pins.

  5. Use pliers or another tool to slide the clip towards the other pin until the clip is securely engaged with the grooves on both pins.

Installing the clip as shown in Steps 4 and Step 5 can be sometimes difficult.

There are a number of approaches that may work for these steps, but a common method is to use a pair of needle nose pliers to grip between the back of the clip and the nearest pin to slide the clip.

Master links are used to connect two ends of a section of chain to create a loop of chain. In order to use a master link, the chain ends should both terminate with inside links. Slide the two pins from the master link into the rollers of the two terminating inside links. Follow the recommended procedure to complete the link installation.

Using the Chain Tool

There are two ways to utilize the #25 Chain Tool, using master links and resetting the chain pin. The included 3mm Allen Wrench works on all three screws of the tool.