This partial calculator treats pin diameter and upper bore allowance as entered dimensions. It reports the selected bore interval, maximum diametral and radial clearance, and a hypothetical equal share for an entered divisor. It does not identify an H7 fit, specify lubrication, model a rolling-tooth mesh, or predict actual load distribution.
Continuous-Bearing Teeth - Selected Pin/Bore Allowance Ledger
Explore an entered pin diameter, upper bore allowance, clearance interval, and hypothetical equal-share divisor.
Equation Used
- Pin diameter and upper bore allowance are entered values.
- The minimum selected bore equals the selected pin diameter.
- The allowance is diametral and converts at 1000 micrometres per millimetre.
- Equal share assumes an abstract divisor n and is not a contact-load model.
- Tolerance standards, fit, gearing, lubrication, loads, wear and safety are excluded.
The secondary figure separates the common-scale pin/bore geometry from an explicitly magnified clearance ledger.
Selected pin/bore allowance ledger
The selected minimum bore equals the selected pin diameter. The entered upper diametral allowance is converted from micrometres to millimetres and added to obtain the selected maximum bore. Maximum radial clearance is one-half of maximum diametral clearance. The equal-share percentage is only 100 divided by the selected divisor.
What the calculator determines
Use it to inspect entered dimensional arithmetic and an explicitly hypothetical equal-share calculation. The figure includes a magnified clearance ledger because the selected micrometre allowance is not visibly resolvable at the pin drawing scale.
Selected relationships
D_min=d; D_max=d+c/1000; diametral clearance range=0 to c; maximum radial clearance=c/2; hypothetical equal share=100/n.
Selected-input example
At 30 mm selected pin diameter and 21 micrometres entered upper bore allowance, the selected bore interval is 30.000 to 30.021 mm, maximum diametral clearance is 21 micrometres, and maximum radial clearance is 10.5 micrometres. A divisor of 2.5 gives a hypothetical equal share of 40 percent.
Not a fit or rolling-contact design
ISO tolerance grade and zone, shaft tolerance, actual clearance distribution, temperature, surface finish, roundness, bearing construction, pocket geometry, contact ratio, deformation, friction, lubrication delivery, loads, fatigue, wear and safety are excluded.
Questions
Is the entered allowance an H7 tolerance?
No. H7 depends on nominal-size range and ISO 286 rules. This candidate labels the value only as an entered upper bore allowance.
Is 100/n an actual load per pin?
No. It is a hypothetical equal-share arithmetic result; real contact load depends on geometry, stiffness, clearances and deformation.
Why is clearance magnified?
A micrometre-scale clearance is too small to see beside a millimetre-scale pin, so the separate clearance bar is intentionally magnified and labeled.
Authoritative references
- NIST Guide to the SI, Chapter 6 — documents milli and micro as SI prefixes.
- NIST Guide to the SI, Chapter 7 — gives examples expressing micrometre-scale dimensions in millimetres.
- University of Florida Design Lab reaming guide — illustrates hole tolerance zones and notes the nominal-size dependence of an H7 example.
References & Further Reading
- Wikipedia contributors. Lantern gear. Wikipedia
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