Controlled product-data arithmetic
Documented Roller-Chain Reference Ratio Worksheet
Normalize dimensions and mass for one exact chain product/configuration, then compare one documented tensile reference force with one established applied chain tension. The output is not an allowable working load, fatigue rating, ISO conformity check or chain selection.
Controlled chain-data record
Arithmetic implemented
ΔF = Freferens − Fapplied
Freferens is exactly the documented tensile reference identified by the user, such as a product minimum tensile force; Fapplied is the maximum applied chain tension established by a separate controlled calculation or test for the stated event. The ratio is dimensionless and the difference is force. Neither quantity is automatically a design resistance, safety factor, margin of safety, allowable load or service-life prediction.
Pitch, roller diameter, inner width and mass per length are converted and recorded only. Their nominal/minimum/maximum qualifiers are not inferred. No designation is decoded, no ISO row is synthesized, and no simplex value is scaled to duplex or triplex.
| Antal | Conversion used | Internal route |
|---|---|---|
| Längd | 1 in = 25.4 mm exactly | Pitch, roller diameter and inner width become mm |
| Mass per length | 1 lb/ft = 0.45359237/0.3048 = 1.4881639435695538 kg/m | Mass per length becomes kg/m |
| Kraft | 1 lbf = 4.4482216152605 N; 1 kN = 1000 N exactly | Both forces become N before division/subtraction |
The inch, avoirdupois pound, international foot and pound-force conversions follow NIST SP 811 Appendix B. Changing units must not change the physical ratio or force difference.
Current ISO lifecycle and scope
ISO 606:2015, Edition 4 is Published and at stage 90.92 “to be revised”; ISO/CD 606 is under development. Its public scope covers characteristics of short-pitch precision roller and bush chains and associated sprockets for power transmission and allied applications, including dimensions, tolerances, length measurement, preloading, minimum tensile strengths and minimum dynamic strength. It excludes cycle and motorcycle chains except for the stated sprocket clause.
ISO 10823:2004, Edition 2, with Corrigendum 1:2008 remains Published, was confirmed in 2024 and is also at stage 90.92 “to be revised.” Its public abstract describes a chain-drive selection procedure for specified industrial operating conditions and approximately 15,000 h life expectancy, while advising supplier consultation because load, environment and maintenance vary.
The licensed ISO 606 tables, tolerances, tensile-test details, dynamic-strength values and ISO 10823 selection equations/ratings are NEEDS_LICENSED_SOURCE. This worksheet does not reproduce, interpolate or certify them.
Manufacturer evidence: breaking force is not working capacity
Renold’s official article Breaking Load is not the way to Specify Chain warns that wear and fatigue matter and that normal chain should not operate near breaking load. The official SKF Transmission Chains catalogue requires a selection procedure using application, speed, temperature and other factors, including starts, reversing load and lubrication.
Published numerical check
The official Renold Chain Designer Guide, worked example 1 on printed page 40, states total chain working load 1,318 N, axial breaking force 19,000 N and a reported ratio 14.4. This worksheet returns 19,000/1,318 = 14.4157815, which rounds to 14.4. The printed fraction visibly drops a zero in its numerator, but the stated 19,000 N and the published 14.4 result establish the intended arithmetic; the independent test retains the consistent values.
Why the old strand factors and table were removed
The same Renold guide, printed page 44, lists ISO 606 tensile strengths for its table. For 06B it shows 8,900 N (simplex), 16,900 N (duplex) and 24,900 N (triplex): ratios of about 1.899 and 2.798, not the former universal 1.7 and 2.5. Other sizes have different ratios. It also lists 40B-1 minimum inside width as 39.30 mm, while the former site table displayed 38.10 mm. Product mass values differed from the site in many rows and are not safely converted by a strand multiplier. These examples prove the old generated table/output was not source-faithful.
NIST SP 811 Appendix B.8 supplies the unit conversion basis.
| Former content or behavior | Problem and correction |
|---|---|
| Simplex tensile force ×1.7 for duplex and ×2.5 for triplex | Published manufacturer/ISO-labelled rows do not follow universal constants and the ratio varies by chain size. Exact assembly values must now be entered; no strand factor exists in code. |
| “Allowable working load” = minimum breaking load / user safety factor | Breaking force is not a fatigue/power/service rating. The output is now only an explicitly non-design reference ratio and arithmetic difference, with no allowable load or verdict. |
| Typical safety factors 7–10 normal and 10–12 shock | The cited ranges had no selected application, life, environment or source and generalized guidance outside its context. They were removed; ISO 10823 and manufacturer selection procedures remain external. |
| Hard-coded “ISO 606” dimensions, tensile force and mass table | Values were unsourced, sometimes rounded upward, one checked width was wrong, and mass is product-specific. The table was removed; each value now requires exact product/source/qualifier provenance. |
| 40B inner width 38.10 mm | The checked Renold ISO 606 table gives 40B-1 minimum inside width 39.30 mm. The replacement does not silently substitute another source; it records the controlled current value entered by the user. |
| Mass scaled by the same strand factors | Published simplex/duplex/triplex mass values are not generated by the tensile multipliers and vary with construction. Direct exact-assembly mass input replaces scaling. |
| F = P/(vη) with η≈0.97–0.98 | The FAQ supplied an efficiency default without defining the power boundary or the omitted dynamic/centrifugal/transient actions. The worksheet requires an externally established maximum chain tension and performs no power-to-load selection. |
| Defaults, presets, auto-calculation, partial parsing and innerHTML | These created an immediate “OK/insufficient” decision from example values. The replacement starts blank, requires provenance and confirmation, validates complete finite numbers and writes results with textContent. |
