Flexible shaft without casing

These shafts are used for short distances in short duty cycle applications. They are designed for control type applications for transferring slow motion from one point to another. The shaft is unsupported by casing and therefore will not respond well to long lengths where it may tend to helix. Due to a lack of casing, it will not retain grease. These shafts should not be run at high speeds for long periods of time, as they will dry out, heat up, and fail.

Uni-Directional or Bi-Directional

Our shaft coupling services comprises unidirectional and bidirectional implies the transmission of power
in one direction and power transmission in both directions between shafts.

Uni-Directional (Power-FLEX™)

These shafts are designed for continuous operation, maximum torque carrying ability, and torsional stiffness in only one direction of rotation: either clockwise or anti-clockwise when viewed from the driving end. The performance of a Uni-directional shaft will fall off dramatically if operated in the opposite direction.

Bi-Directional (Steady-FLEX™)

These shafts are designed to rotate in both clockwise and anti-clockwise directions. They have more balanced physical properties that allow them to operate in either direction of rotation.

Torque Requirements

This is the maximum continuous torque (in-lb or N-m) that you will be transmitting through the shaft. This will determine the diameter of the shaft required for your application. Start up torques-or short duration peak torques- may safely be 20% higher. If you are measuring your load in Horsepower, you must convert to in-lb using the Torque-Horsepower conversion chart , or use the following formula:

Torque =

HP x 63,000

RPM

Minimum Requirements

There is a direct relationship between operating torque and operating radius; as the radius gets smaller the torque capacity of the shaft reduces. In tighter bends the wires rub against each other more forcefully increasing the friction, heat, and stress. The minimum radius can be calculated using the following formula:

R =

x ² + y ²

Charts to Select the Correct Shaft

Depending on your application's direction of rotation (see diagram above) and measurement units, click
on the appropriate chart to choose the correct Flexible Shaft for your application:

Uni-Directional (English Units) chart

Uni-Directional (Metric Units) chart

Bi-Directional (English Units) chart

Bi-Directional (Metric Units) chart

Bending or Torsional Stiffness

If two or more types of shafts of the same diameter meet your torque requirements, it is desirable to choose the shaft with the lowest bending stiffness, since it correlates to lower "torque to rotate" which is a measure of the internal friction in the shaft. If torsional deflection i.e. the shaft twisting under load is a concern, then look at the corresponding torsional stiffness values for the shafts that meet your torque and minimum radius requirements . From these, choose the shaft that best fits your deflection needs.

Operating Speed

This is the maximum continuous speed in RPM's for a shaft under load. Check the Specification Charts to see that your speed is within the design limits of the shaft. As the speed increases the level of power transmitted can increase as the torque load is reduced proportionally to the increase in the shaft speed. From this you can see that Flexible Shafts like to be run fast so as to reduce torque load. *Excessive speed, especially in tight bend radii for extended periods, can cause heat buildup and premature failure.

Length

Determine the proper length (in inches) of the overall shaft assembly by closely approximating all bends and offsets.
Measure the length along the centerline of the shaft.

Shaft with Fittings

For shaft applications that do not require casing, use the chart below to choose your fitting(s). Fittings are available in seven mating sizes (A through G) for each size shaft up to .500 inches in diameter. Panel mount fittings (H & I) are available for some sizes. Casing is usually necessary for shaft lengths that exceed 8 inches. Casing is recommended when the environment is dirty, dusty, or corrosive. Casing is also recommended when the shafts are run at high speeds in exposed areas where injury can occur.

Asterisks ( * ) designate which fittings are available for a given shaft diameter.