How to Size an Engineering Class Steel Chain
This guide focuses on adjusting the size of two common
engineering class chains: straight sidebar and offset sidebar chains. Both chain types require pin removal and installation for shortening (reducing length) or lengthening (increasing length). Due to the large size of most of the engineering class steel chains, they feature heavy press fits of the pins within the sidebars. Breaking these press fits requires application of substantial forces. Therefore, you must take careful preparations for chain assembly and disassembly, including the use of specialized pressing equipment, to ensure safety and prevent damage.
How to Shorten an Engineering Class Chain
To shorten an engineered class chain you would normally need to disconnect its links at the desired length. Below you will find step by step instructions for disconnecting chain links on the two most common types of engineered chains.
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Step 1. Identify the Pin Removal Direction. An engineered class chain link pin should be removed in the direction of its head. Typically, it is the wider end of the pin. However, the styles of engineering steel chain link pin heads and fasteners may vary from chain to chain. Therefore, basic knowledge of different pin heads may be required to identify the direction in which the pin will be pressed out.
Step 2. Prepare the Pins for Removal. If the pins are fastened with cotter pins, remove the cotters from one side of the link. If the pins are riveted, grind off the heads of the pins on the side of the link opposite to the pin removal direction. The heads must be ground off flush to the surface of the link plate. If they are not completely ground off, this may cause damage to the inside link bushings when the pins are pressed out.
Step 3. Support the Link. To create a stable force against the force of pressing, support the outer link sidebar from its back surface (inside of the link.)
Step 4. Press the Pins Out. Use appropriate pressing equipment to press the pins out of the top sidebar.
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Step 1. Determine the Pin Removal Direction. Unlike straight sidebar chains that have inner and outer links, offset sidebar chains use links that are identical to each other. Therefore, you will only need to remove one pin after you determine the correct direction of its removal.
Step 2. Remove the Fasteners. Take out the cotter or grind off the head of the pin on one side to prepare it for removal.
Step 3. Support for the Link. Put an anvil with a predrilled hole under the pin. The hole in the anvil should have a diameter greater than the pin head to stabilize the sidebar against the pressing force and allow the pin head to pass through the hole.
Step 4. Press Out the Pin. Use pressing equipment to press the pin out of the link.
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How to Extend an Engineering Class Chain
The main procedure involved in engineered class chain extension is connecting two or more sections of the chain into one to achieve the desired length. The instructions below provide essential guidelines for performing this procedure on the two common types of the engineered class chain.
Note: Because these procedures are performed when the chain is laying on one of its sides, the sidebar facing down is referred to as the “bottom” sidebar and the sidebar facing up is referred to as the “top” sidebar.
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This process assumes that you are connecting an outer link to the two strands of the chain that both have inner links at the ends you are trying to connect.
Step 1. Support the Bottom Sidebar. Position an anvil with a pre-drilled hole underneath one of the holes of the bottom sidebar of the loose outer link. The hole in the anvil should have a larger diameter than the pin hole of the sidebar. Alternatively, if you don’t have an anvil you may use two parallel support blocks positioned at an equal distance from the pin hole.
Make note that if the pin is a press fit, you will need to position anvils underneath each hole of the bottom sidebar.
Step 2. Align the Holes. Place the inner chain link atop of the bottom sidebar, and the top sidebar atop of the inner link. Align the holes of all three parts.
Do the same at the other end of the sidebar if the pin is a press fit.
Step 3. Align and Insert the Pin. Manually insert the pin through the holes making sure the flats or keys on the pin align with any recesses in the sidebars. Push the pin as far as it can go through the sidebars and the inner link.
Repeat the process with the second pin if the pin is a press fit.
Step 4. Press the Pin(s) Into the Sidebar Holes. If the pin is a slip fit, the assembly is straightforward and you won’t need extra pressure to pass the pin through the bottom sidebar.
However, if it's a press fit, you must use pressing equipment to press both pins evenly into the sidebar.
Step 5. Repeat the Steps at the Other End (For Slip Fit Pins.) Repeat steps 1-4 for the second slip fit pin at the other end of the sidebar.
Step 6. Install Retainers. Secure the pins with retainers. If both pins use a single retainer, its sharp end should face away from the direction of the chain travel. If each pin uses a separate retainer, the sharp ends of each retainer should be facing each other (inwardly.)
Step 7. Verify that the joint flexes freely after completing the connection.
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The process of connecting an offset sidebar chain link is similar to connecting a straight sidebar chain. The main difference is that in this case you will be connecting two identical links with one pin.
Step 1. Support and Align. Position a drilled anvil under the pin hole of the wider-end link and insert the narrower-end link between its plates. Align the pin holes of both links.
Step 2. Insert the Pin. Insert the pin through the holes of both links, ensuring any flats or keys on the pin match the corresponding recesses in the sidebar holes.
Step 3. Press the Pin. Press the pin into the bottom plate hole. Use pressing equipment if necessary.
Step 4. Install the Retainer. Install the retainer into the connecting pin.
Step 5. Verify Proper Installation. Confirm that the joint flexes freely after completing the connection.
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