For an ideal single-start auger, geometric lead equals pitch P per shaft revolution. At selected speed N, ideal lead rate is PN, shaft revolutions in time t are Nt, and corresponding ideal lead distance is PNt. These are screw-geometry and timing identities, not bulk-material conveying predictions.
Ideal Auger Lead and Shaft-Timing Model
Explore ideal single-start auger lead and shaft timing without assuming granular material follows the helix exactly.
Equation Used
- The helical flight is single-start with uniform pitch.
- Pitch and shaft speed are constant.
- The outputs describe ideal screw geometry and shaft timing.
- Granular slip, fill, recirculation, inclination, torque, power and wear are excluded.
The ideal lead distance is not measured sand travel or conveying capacity.
Connected shaft and helical flight
The animation shows a single continuous helical-flight projection fixed to a rotating central shaft inside a stationary tube. Changing pitch changes the axial spacing of turns; changing speed changes rotation rate.
The highlighted axial lead dimension is one pitch for a single-start helix. It does not show a sand parcel advancing exactly one pitch per revolution.
What the calculator determines
Select geometric flight pitch, shaft speed and elapsed time. The calculator returns ideal single-start lead per revolution, ideal lead rate, ideal lead distance and shaft revolutions.
It does not calculate material throughput, fill, slip, recirculation, power, torque, wear, inclination effects or a safe operating limit.
Ideal single-start lead identities
ℓ = P, uideal = PN, R = Nt and xideal = PNt. Pitch is entered in millimetres per turn, speed in revolutions per minute and time in minutes.
For multi-start flighting, lead would differ from pitch. Real granular material does not generally move at the ideal geometric lead rate.
Selected-input example
At P = 150 mm, N = 45 rpm and t = 1 min, the shaft makes 45 revolutions. The ideal single-start lead rate is 6,750 mm/min and the corresponding geometric lead distance is 6.75 m.
This is not a claim that sand travels 6.75 m or that any mass flow is achieved.
Scope and correction boundary
The former page labeled screw lead as sand advance and added unsupported throughput, material, speed, wear, failure, maintenance, product and operating claims. Those claims, the fabricated glass-batch example and unrelated actuator section are removed.
A real conveying model requires auger diameter, shaft diameter, fill, bulk density, inclination, friction, slip, clearances and drive load.
Questions
Does pitch equal sand travel per revolution?
No. It equals ideal geometric lead per revolution for a single-start helix.
Does the calculator predict throughput?
No. No material volume, density or fill model is included.
Does shaft speed determine safe operation?
No. Torque, power, wear, guarding, bearings and material behavior are excluded.
What does the animation establish?
Only a connected rotating shaft, continuous single-start helix and pitch spacing.
Technical references
- NIST Special Publication 811 — SI units and coherent quantity notation.
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