5 Mistakes I Made Buying Roller Chains (and the Checklist That Fixed It)

Who This Checklist Is For (And What It Solved)

If you're sourcing roller chains for conveyor systems, gearboxes, or heavy equipment — especially if you're working with a brand like Rexnord — you've probably faced this: the part arrives, doesn't fit, and now you're down a week while the wrong order sits on your dock.

I've been there. More than once. In my first year (2017), I ordered the wrong pitch on a 50-piece order. Every single item had to go back. That mistake cost about $1,200 in restocking fees plus a 10-day delay. The second time (uggh, yes, it happened again), I got the bore size wrong on a coupling side. Another $890 down the drain.

After the third rejection in Q1 2024, I created a pre-order verification checklist. We've caught 47 potential errors using it in the past 18 months. Here's exactly what's on it — and the mistakes each step prevents.

Step 1: Verify the Chain Series, Not Just the Part Number

The mistake I made: I assumed that if the part number starts with "RS" (roller chain standard), any RS number would work. Wrong. The series — RS40, RS50, RS60, RS80 — determines pitch, roller diameter, and pin diameter. I ordered RS60 when the spec called for RS50. The pins were too thick. Didn't fit the sprocket.

What I do now: Before I even look at the drawing, I check the series code against the application. Rexnord's catalog uses a clear code system (e.g., RS80-2 for double-strand chain). If you're looking at a Rexnord CAD file, the series is baked into the drawing number. But here's what most people don't realize: that CAD file might reference the series in a note or layer, not the filename itself.

Checklist item: Confirm the chain series matches the sprocket pitch diameter and tooth profile.

Step 2: Confirm the Strand Count — Don't Assume

The mistake I made: On a multi-strand conveyor application, I ordered single-strand chain because the drawing only showed one line. It was a duplex application (two strands running parallel). The single strand couldn't handle the load. The conveyor kept slipping.

What I do now: I look at the drive specification — not just the drawing. If the motor is sized for a specific in-lb torque, I calculate the required tensile strength across strands. A single RS80 chain might be rated for 12,000 lbf, but a duplex (RS80-2) can handle 24,000 lbf. If you need 20,000 lbf, a single strand is a failure waiting to happen.

Checklist item: Verify strand count from the torque spec, not the visual representation.

Step 3: Check the Bore and Keyway on Couplings (This One Stung)

The mistake I made: I ordered a Rexnord coupling for a gearbox-to- motor connection. The coupling body was correct, but the bore size was for a 1.5" shaft — our motor had a 1.875" shaft. The keyway was also wrong (mil-spec vs. square key). The coupling literally wouldn't slide on.

That error cost $890 in redo plus a 1-week delay. Here's something vendors won't tell you: the bore size on the coupling drawing isn't always the bore size on the tag. Sometimes the part number covers a range, and the actual bore is machined at the factory per the order. If the order entry had a typo, the bore comes wrong.

What I do now: I verify bore diameter, keyway width, and keyway depth against the actual shaft — not the drawing. I also check if it's a standard or metric keyway. Rexnord offers both, and they're not interchangeable.

Checklist item: Confirm bore, keyway, and shaft dimensions match the physical equipment (not just the CAD file).

Step 4: Verify Material Compatibility — Especially in Harsh Environments

The mistake I made: I ordered standard carbon steel roller chain for a conveyor system in a food processing facility. The chain rusted within weeks. The customer wasn't happy (understatement). I should have specified stainless steel or nickel-plated.

What I do now: I check the application environment: temperature range, humidity, chemical exposure, washdown frequency. Rexnord offers several material options: standard carbon steel, stainless steel (304 or 316), and nickel-plated for light corrosion resistance. If the application involves high-pressure washdowns, stainless is the only option that lasts. I learned that the hard way.

Checklist item: Confirm material grade based on environmental conditions — not just the standard catalog option.

Step 5: Verify Attachment Type and Spacing — The One Everyone Misses

The mistake I made: For a conveyor system, I ordered chain with standard A-1 attachments (one hole per pitch). The conveyor design required a special extended pin with a specific hole spacing. The standard attachment wouldn't work. The entire chain had to be reordered.

What I do now: I look at the conveyor layout: where attachments are needed, their spacing (every pitch, every other pitch, every third pitch), and the attachment style (straight, extended pin, bent tab). Rexnord offers dozens of attachment types (A-1, A-2, K-1, K-2, etc.). The wrong one can cause the product to shift or jam.

Checklist item: Match attachment type and spacing to the conveyor design — not the standard catalog configuration.

Common Traps to Avoid

Relying solely on CAD files for dimensions. We've seen CAD files where the bore size was listed as a default (like 1.5") but the actual part was machined to 1.875". Always verify against the physical equipment.

Overlooking country-of-origin variants. Rexford has manufacturing in India, Brazil, China, and Europe. A chain made in one location might have slightly different heat treatment or plating thickness than another. If your application is highly specific, ask for the factory origin. (This was true in 2022, anyway.)

Forgetting the lubrication spec. Roller chains require lubrication. Some chains come pre-lubed (break-in oil), but some require field lubrication. If you order a chain that needs oil bath lubrication and your application is dry-running, failure is guaranteed.

Prices as of January 2025: Standard RS80 single-strand roller chain runs about $15-25 per foot. Duplex RS80-2 runs $35-50 per foot. Stainless steel adds 40-60%. Verify current pricing at your distributor, as rates may have changed.

The vendor who said 'this isn't our strength — here's who does it better' earned my trust for everything else. Similarly, I learned to say 'I'm not sure about this spec — let me verify' rather than assume. That honesty saved me more money than any catalog shortcut ever did.