Balancing services › Augers & Screw Conveyors

Auger & Screw Conveyor Balancing — In-Situ, at Operating Speed

Grain blowers, feed augers and industrial screw conveyors are long, slender rotors that develop two-plane unbalance the moment a flight wears unevenly or a weld shifts the mass distribution. We balance them on site, at operating speed — no workshop removal, no guesswork — restoring smooth, reliable material flow and stopping premature bearing failures in their tracks.

Get the Balanset-1A Ask our engineer

Auger and screw conveyor being balanced on site at operating speed

In short: Auger and screw conveyor balancing is performed in-situ, at normal operating speed, using the two-plane influence-coefficient method. Vibration accelerometers are mounted on both end-bearing housings and a laser tachometer measures shaft speed; the Balanset-1A calculates the exact correction mass and angle for each plane. No rotor removal, no trough disassembly — a typical job is complete in under one hour, reducing vibration by 70 % or more and extending bearing life by a factor of eight or more.

Signs your auger or screw conveyor is out of balance

Screw conveyors run at relatively modest speeds, yet even small mass eccentricities travel the full length of the shaft and create surprising levels of vibration. Watch for these warning signs:

Once-per-revolution shake A steady vibration locked to shaft speed is the textbook signature of mass unbalance — the dominant 1× RPM component in the vibration spectrum.

Bearing failure at both ends Long screws distribute unbalance forces to both end bearings, wearing out housings at both ends far ahead of their rated L₁₀ life.

Structural rattling The trough, frame or support legs vibrate noisily even at low throughput, signalling that the rotor is exciting the surrounding structure.

Product pulsing or surging Vibration-induced trough movement disrupts consistent material flow and causes uneven, unreliable discharge rates.

Seal wear & leakage End-seal faces grind unevenly when bearing housings oscillate laterally, causing dust or product to escape at the shaft entry points.

Cracked or loose flights Fatigue from cyclic bending loads shows up as cracked flight welds, loose fasteners or backing-out bolts on removable spiral sections.

Why augers lose balance — and what it costs

A screw conveyor rotor is fundamentally different from a compact fan or pump impeller: its mass is spread over a long, relatively flexible shaft, making it inherently susceptible to two-plane unbalance that a single correction weight cannot fix. Unbalance builds gradually through uneven abrasive wear of the flights, product build-up on one side of the spiral, corrosion pitting, and repair welds or replacement flight sections that alter the mass distribution along the shaft. In grain blowers and pneumatic transfer augers the spiral also spins fast enough for centrifugal force to magnify even a modest eccentricity into hundreds of newtons of shaking force.

Operators often mistake the worsening vibration for a structural problem and respond by adding mounting bolts or stiffer frames — masking the symptom while the root cause continues to grind down bearings, damage seals and fatigue welds. Because centrifugal force grows with the square of rotational speed, a small mass offset that causes modest vibration at 300 rpm becomes four times worse at 600 rpm. Correcting both planes of unbalance in a single on-site visit eliminates the load at source, and the machinery runs smoothly for years rather than months.

×10bearing life when vibration is halved

−70%typical vibration drop after one session

2planes corrected in one visit

<1htypical on-site job

Why halving vibration multiplies bearing life

ISO 281 defines rolling-bearing rating life as L₁₀ = (C/P)^p, where P is the dynamic load on the bearing and the exponent p = 3 for ball bearings and 10/3 for roller bearings. Residual unbalance is that rotating load P, and vibration amplitude tracks it directly — so cutting vibration in half halves P and multiplies bearing life by 2^p: about 8× for ball bearings and ~10× for roller bearings (2^10/3 ≈ 10). Run your own numbers in our bearing-life calculator.

How we balance an auger — step by step

The Balanset-1A uses the influence-coefficient method, adapted here for the two-plane reality of long screw rotors. The same systematic procedure can be carried out by your own maintenance team:

Mount the sensors. Vibration accelerometers are fixed to both end-bearing housings and a laser tachometer is aimed at a reflective strip on the shaft. No disassembly is required — the screw runs at normal operating speed throughout.
Measure the baseline. One full-speed run captures vibration amplitude and phase angle at each bearing plane simultaneously, establishing the current two-plane unbalance state.
Add a trial weight. A known test mass is clamped to the shaft or a flight at a precisely measured angular position near one end. The rotor runs again so the device records how both planes respond to the known perturbation — the influence coefficient.
Let the device calculate. The Balanset-1A solves the two-plane influence-coefficient matrix and outputs the exact correction mass and clock angle for each correction plane. A second trial weight at the opposite end refines the solution if needed.
Fit the correction weights. Correction masses are welded, bolted or clamped at the calculated positions on both ends of the screw rotor, using the calculated angular placement.
Verify and document. A final measurement run confirms residual unbalance meets the ISO 21940-11 grade required for the application. The Balanset-1A generates a printed report showing before-and-after figures at each plane.

What we balance

Grain-elevator and grain-blower augers
Feed-mill and feed-conveyor screws
Horizontal screw conveyors in bulk-material handling
Inclined and vertical screw lifts
Cement and aggregate screw feeders
Extruder feed screws (removable rotor)
Agricultural combine harvester unloading augers
Dust-collection and ash-conveyor screws
Pneumatic transfer augers and grain blowers
Custom spiral conveyor rotors of any length

Tolerances & standards

ISO 21940-11 (formerly ISO 1940-1) governs rigid-rotor balance quality grades. Long-shaft screw rotors typically fall into quality grade G 6.3 (general industrial machinery) or G 2.5 where smoother operation is required — for example, high-speed grain blowers or conveyors feeding precision metering equipment. The standard defines the permissible residual specific unbalance e_per as a function of rotor service speed, giving a clear, measurable acceptance criterion.

For high-speed grain blowers that move material pneumatically, the fan-balancing limits of ISO 14694 or the machine-builder’s own specification may also apply. We balance to the grade your application requires and supply a documented residual-unbalance result — in g·mm per plane — alongside the grade achieved. Use our residual-unbalance calculator to find the permissible tolerance for your rotor before starting.

The Balanset-1A — your complete field-balancing kit

Everything on this page is done with one portable instrument: the Balanset-1A. It is a two-channel dynamic balancer and vibration analyzer that balances screw conveyor and auger rotors in their own bearings, at operating speed, using the 3-run influence-coefficient method — the software calculates the exact correction mass and angle for each plane and saves a report.

Complete Balanset-1A balancing kit with sensors, laser tachometer, scale and case

What’s in the Full Kit

€1,975 · Full Kit, in stock, VAT invoice

Interface measurement unit (USB, 2 channels)
Two vibration accelerometers (4 m cable, 10 m optional)
Laser tachometer / optical phase sensor (50–500 mm)
Magnetic stand for the sensor
Digital scale for trial & correction weights
Windows balancing & analysis software
Plastic transport case

View the Balanset-1A Ask our engineer

Recommended

Full Kit

Unit · 2 sensors · laser tachometer · magnetic stand · digital scale · software · transport case. Everything needed to start balancing out of the box.

OEM

OEM set

Unit · 2 sensors · laser tachometer · software. For integrators who already have a stand, scale and case, or who embed the unit into a balancing machine.

Key technical specifications
Parameter	Value
Measurement channels	2 (single- & two-plane balancing)
Vibration velocity range	0.05–100 mm/s
Frequency range	5–300 Hz
Measurement accuracy	±5% of full scale
Method	3-run influence-coefficient (1 or 2 planes)
Analysis	Amplitude & phase at 1×, FFT spectrum & waveform, saved reports
Laptop	Not included (Windows PC, available on request)

✓ In stock✓ DHL Portugal €35✓ DHL worldwide €110✓ 2-year warranty✓ VAT invoice✓ Engineer support

Field balancing vs balancing machine — which is right for your screw rotor?

Comparison: in-situ field balancing vs dedicated balancing machine for augers and screw conveyors
Factor	Field balancing (Balanset-1A)	Balancing machine (workshop)
Rotor removed from conveyor?	No — runs in place	Yes — full disassembly required
Trough or casing disconnection?	No	Yes
Production downtime	Sensor fitting only (<15 min)	Hours to days (pull, transport, balance, reinstall)
Balancing speed	Actual operating speed & load conditions	Separate low-speed spindle
Accounts for shaft sag & flex	Yes — full assembly balanced in situ	Rotor in isolation, no real mounting
Two-plane correction	Yes — both end bearings in one visit	Yes
Standards met	ISO 21940-11 (G 6.3 / G 2.5)	ISO 21940-11
Equipment cost	€1,975 (Full Kit)	€10,000 – €50,000+
Typical job time	<1 hour on site	1–3 days total

Field balancing is the preferred choice whenever the screw rotor can run and the rigidity criterion is satisfied. A workshop machine remains appropriate for new-build rotors with zero run time, or for very large or damaged rotors that require complete disassembly for other repairs.

Real auger-balancing cases

Industrial screw conveyor

Two-plane field balancing of a bulk-material screw conveyor rotor, achieving ISO 21940-11 G 6.3 and eliminating recurring bearing failures.

Free auger & screw conveyor calculators

Centrifugal force from unbalance Residual unbalance (ISO 1940) Trial weight calculator Bearing-life calculator Tip speed calculator

Auger & screw conveyor balancing FAQ

Does a screw conveyor really need two-plane balancing?

Almost always, yes. The mass of a screw rotor is spread along its length, so unbalance at one end does not cancel unbalance at the other. Correcting a single plane can actually worsen vibration at the opposite bearing. The Balanset-1A handles both planes simultaneously in a single visit, with accelerometers at each end-bearing housing.

Can the auger stay in the trough during balancing?

In most cases yes. Field balancing is performed with the rotor in its own bearings, running at normal operating speed, without removing the screw from the trough or conveyor casing. You need safe access to both end-bearing housings to fit the vibration sensors, and to the shaft or flights to add and position the correction weights during the job.

What balance grade applies to screw conveyors?

ISO 21940-11 grade G 6.3 is the standard for general industrial machinery including most horizontal screw conveyors. High-speed grain blowers and conveyors feeding precision metering equipment are typically balanced to G 2.5. The standard defines permissible residual specific unbalance e_per in g·mm/kg as a function of service speed — use our residual-unbalance calculator to determine the exact tolerance for your rotor before starting.

Our auger is still rough after replacing worn flights — why?

Replacement flight sections rarely have identical mass to the originals, and the attachment welds add further asymmetry. The repair itself almost always introduces new two-plane unbalance. Balancing after any significant flight repair or screw section replacement is standard practice, not an optional extra.

How much correction weight is typically needed?

It varies with rotor mass and severity of unbalance, but it is usually a very small fraction of the rotor weight — commonly a few hundred grams on a large agricultural auger. The trial-weight calculator helps you size an appropriate test mass before you start, minimising the risk of over-disturbing the rotor.

Can we do this ourselves with the Balanset-1A?

Yes. The Balanset-1A is designed for maintenance teams to operate without specialist balancing experience. It walks you through each measurement run with on-screen prompts, solves the two-plane influence-coefficient matrix automatically, and outputs a correction result and final report. Our community forum has engineers available if you encounter an unusual rotor or want to verify your approach.

Learn the theory

Two-plane balancing Field balancing Dynamic balancing Residual unbalance Balance quality grades

Balance your auger or screw conveyor — in place, today

The Balanset-1A handles the full two-plane correction that long screw rotors demand, completing the job at running speed with a documented result showing exact residual unbalance at each correction plane — to ISO 21940-11 G 6.3 or G 2.5, whichever your application requires. No dismounting, no lost production.

View the Balanset-1A Ask a question on the forum