Double Sprockets for Two Single Chains American Standard
Korea Ever-Power American standard double simplex sprockets drive two parallel single-strand chains simultaneously from one shaft. The hub carries two tooth rows machined to ANSI B29.1 profile, separated by the Cmax dimension — the maximum permitted centre-to-centre spacing between the two chain strand centrelines. Each chain run is entirely independent: separately tensioned, separately replaceable, carrying its own load. This is the defining advantage over a duplex sprocket and duplex chain, where both strands are mechanically linked.
#40 – #80
Chain Size Range
Z=9 – 30
Tooth Count Range
2 Strands
Two Independent Chains
ANSI B29.1
Standard
Double Sprockets for Two Single Chains – American Standard
The American standard double simplex range covers chain sizes #40 through #80 in simplex configuration, tooth counts Z=9 to Z=30. Stock bore is standard — the hub is supplied with pilot bore, machined to your shaft diameter and keyway to ASME B17.1 on order.
Typical applications: wide slat conveyors in American food and automotive plants, combine harvester elevator drives in ANSI-chain markets (North America, Korea, Australia), bucket elevator head-shaft drives, and wide-track agricultural machinery where chain spacing must accommodate wide slat bars or flight attachments at a spacing not achievable with standard duplex chain pitch.
⚖️ Load sharing between two strands
On a double simplex drive, load is shared between the two independent chains. However, equal load sharing requires:
- Both chains the same chain number and grade
- Both chains tensioned to equal sag independently
- Both sprockets co-axial — machined in single chucking
- Both driven sprockets at equal spacing on the driven shaft
Mismatched chain elongation causes one strand to carry the majority of the load — monitor chain sag on both strands at each maintenance interval.
When to Choose Double Simplex over ANSI Duplex Chain
ANSI duplex chain (#40-2, #50-2, #60-2 etc.) and double simplex sprockets are NOT interchangeable — they are different design solutions for different operational needs. The choice between them affects maintenance cost, chain replacement strategy and conveyor width flexibility.
| Factor | Double Simplex Sprocket + 2× Single Chain | Duplex Sprocket + 1× Duplex Chain |
|---|---|---|
| Chain replacement | Replace one strand at a time | Replace full duplex chain (both rows together) |
| Conveyor width flexibility | Any spacing up to Cmax — slat width not constrained by duplex pitch | Fixed by duplex chain inner width increment |
| Independent tension control | Yes — each strand independently adjusted | No — single take-up tensions both rows equally |
| Chain cost per unit | Two rolls of standard simplex — widely available | Single roll of duplex — lower weight |
| Sprocket cost | Higher — double tooth row hub | Lower — standard duplex hub |
| Best for | Wide conveyors, asymmetric loading, MRO-critical drives | Standard width conveyors, even loading, lower initial cost priority |
Key: Z = teeth | de = tip dia. (in) | dp = pitch circle dia. (in) | Cmax = max chain strand centreline spacing (in) | B = hub width per side (in) | Bore max = max stock bore (in) | All: ANSI B29.1 tooth profile, C45 steel, stock bore
Specifications — #40 through #80
#40 Double Simplex | Pitch ½″ / 12.70 mm | Cmax ≈ 1.00″ (25.4 mm)
| Z | de (in) | dp (in) | Cmax (in) | B per side (in) | Bore max (in) |
|---|---|---|---|---|---|
| 9 | 1.670 | 1.440 | 1.000 | ⅞ | ¾ |
| 12 | 2.170 | 1.931 | 1.000 | ⅞ | ¾ |
| 15 | 2.650 | 2.408 | 1.000 | ⅞ | 1 |
| 17 | 2.980 | 2.724 | 1.000 | ⅞ | 1 |
| 21 | 3.620 | 3.360 | 1.000 | ⅞ | 1¼ |
| 25 | 4.260 | 3.988 | 1.000 | ⅞ | 1½ |
| 30 | 5.060 | 4.775 | 1.000 | ⅞ | 1½ |
#60 Double Simplex | Pitch ¾″ / 19.05 mm | Cmax ≈ 1.50″ (38.1 mm)
| Z | de (in) | dp (in) | Cmax (in) | B per side (in) | Bore max (in) |
|---|---|---|---|---|---|
| 9 | 2.490 | 2.153 | 1.500 | 1¼ | 1 |
| 15 | 3.990 | 3.593 | 1.500 | 1¼ | 1½ |
| 17 | 4.460 | 4.071 | 1.500 | 1¼ | 1½ |
| 21 | 5.400 | 4.970 | 1.500 | 1¼ | 2¼ |
| 25 | 6.360 | 5.875 | 1.500 | 1¼ | 2¼ |
#80 Double Simplex | Pitch 1″ / 25.40 mm | Cmax ≈ 2.00″ (50.8 mm)
| Z | de (in) | dp (in) | Cmax (in) | B per side (in) | Bore max (in) |
|---|---|---|---|---|---|
| 9 | 3.340 | 2.871 | 2.000 | 1½ | 1¼ |
| 15 | 5.270 | 4.784 | 2.000 | 1½ | 2 |
| 17 | 5.930 | 5.414 | 2.000 | 1½ | 2 |
| 21 | 7.200 | 6.620 | 2.000 | 1½ | 3 |
| 25 | 8.480 | 7.831 | 2.000 | 1½ | 3 |
#50 tables available on request. All bores stock bore — machined to your inch shaft size and ASME B17.1 keyway on order. Non-catalogue tooth counts Z=10–30 available. Contact us with chain number, tooth count and bore requirement.
Matching Chain & Related Products
Leaf Chains
BL and LH series leaf chains for forklift masts, industrial door drives, and hoist mechanisms. Tensile ratings from 11 kN to over 1,600 kN.
Engineering Chains
Welded steel, cast iron, and forged chains for heavy-duty industrial conveying in steel mills, cement plants, mining, and chemical processing.
Stainless Steel Chains
SUS304 and SUS316L roller chains for food, pharmaceutical, and chemical environments. Suitable for washdown, elevated temperature, and corrosive media.
Agricultural Chains
CA, CC, and corn-chain series for combine harvesters, cotton pickers, balers, and spreading equipment. ISO 487 / ASME B29.100 standard.
Additional information
| Editor | Cxm |
|---|
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