Right-Hand vs. Left-Hand Screw Conveyor Flights: Understanding Orientation, Pitch, and Construction

In bulk material handling, even small design details can have a big impact on performance. One of the most critical—and often overlooked—is the orientation of the screw conveyor flights. Choosing between right-hand and left-hand flights isn’t just a technicality. It determines the direction your material moves, and getting it wrong can lead to backflow, clogging, and costly downtime.

At ISC Manufacturing, we help operators avoid these pitfalls by ensuring every screw conveyor is engineered for their process—from flight orientation to pitch and construction.

What Does Flight “Hand” Mean?

The flighting is the helical blade welded to the center shaft of your screw conveyor. As the shaft rotates, the flights push material along the trough or tube. But here’s the key:

The direction of rotation and the flight’s orientation (right-hand or left-hand) determine which way your material flows.

Right-Hand Flight (The Industry Standard)

A right-hand screw moves material forward when the shaft rotates clockwise (CW), viewed from the discharge end.

This is the most common configuration because most motors and gearboxes are designed to rotate clockwise.

It’s used in the majority of horizontal and inclined conveyors for powders, grains, aggregates, and other free-flowing materials.

Left-Hand Flight (The Specialty Option)

A left-hand screw moves material forward when the shaft rotates counterclockwise (CCW), viewed from the discharge end.

Left-hand flights are less common but essential in certain situations:

When multiple screws are arranged in opposing directions to feed into or away from a central point.
In mirrored systems where left-hand screws are required for symmetrical layout.

What is Flight Pitch?

Pitch is the distance between two flights. It affects how much material moves with each rotation:

Short (Half) Pitch
The flight spacing is half the screw diameter. It’s ideal for inclined applications or for moving sluggish, sticky, or abrasive materials because it provides better material control.
Variable Pitch
The flights are spaced closer together at the inlet to control flow and then gradually spaced farther apart downstream for full capacity. Useful for metering and preventing surging.
Long Pitch
Flights are spaced farther apart than the screw diameter. This design provides faster material movement and is ideal for light, free-flowing materials.
Ribbon Flight
Flights have an open center, which prevents sticky or viscous materials from clogging around the shaft. Common in mixers or shaftless screw conveyors.
Cut/ Cut and Folded Flight
Notches are cut into the outside edge of the flights. This helps aerate or mix materials and reduce buildup. Can cut and fold segments to lift and tumble the material, increasing mixing and agitation. Often used in processing applications.
Paddle Flight
Instead of continuous flights, paddles are mounted at intervals around the shaft. These create deliberate agitation and mixing as material moves through the conveyor.

The right pitch keeps material moving smoothly and prevents surging or clogging.

Helicoid vs. Sectional Flights

You’ll also see flights described as helicoid or sectional:

Helicoid Flights – Formed from a continuous strip of steel. Best for uniform, light-to-moderate duty applications.
Sectional Flights – Individual segments cut and welded to the shaft. Stronger, more customizable, and ideal for abrasive or heavy-duty materials.

At ISC, we build both. Which is best depends on your material and system demands.

Diagram of a helicoid screw conveyor showing a side view, end view, and details of Screw Conveyor Flights construction and mounting methods for both Left-Hand and Right-Hand Screw Conveyors.

Diagram illustrating sectional Screw Conveyor Flights, including a side view, a helical cross-section, and an end view, with accompanying descriptive text on Left-Hand and Right-Hand Screw Conveyor configurations.

Why Flight Orientation Matters

Choosing the wrong hand or pitch can cause:

Material flowing the wrong way
Blockages or backflow at inlets/discharges
Overloading of upstream or downstream equipment
Premature wear and increased maintenance
Costly downtime while waiting for replacement parts

ISC Makes It Simple

Flight orientation may seem like a small detail, but it can make or break your system. Whether you’re replacing a screw or designing a new screw conveyor, ISC ensures every part is engineered for your material and your process. At ISC, we take the guesswork out of conveyor design. Our team confirms rotation direction, flight hand, pitch, and flight construction early in the process. We also build: