{"id":839,"date":"2026-06-24T09:16:00","date_gmt":"2026-06-24T09:16:00","guid":{"rendered":"https:\/\/oldhamcoupling.net\/how-to-choose-the-right-oldham-coupling-for-your-application-a-complete-guide\/"},"modified":"2026-06-24T09:48:10","modified_gmt":"2026-06-24T09:48:10","slug":"how-to-choose-the-right-oldham-coupling-for-your-application-a-complete-guide","status":"publish","type":"post","link":"https:\/\/oldhamcoupling.net\/hi\/how-to-choose-the-right-oldham-coupling-for-your-application-a-complete-guide\/","title":{"rendered":"How to Choose the Right Oldham Coupling for Your Application: A Complete Guide"},"content":{"rendered":"

With dozens of Oldham coupling variants available \u2014 spanning bore sizes from 3 mm to over 100 mm, disc materials from acetal to PEEK to steel, and hub styles from set-screw to clamp to keyed \u2014 selecting the right one for a specific application is not as straightforward as it might appear. An undersized coupling fails prematurely. An oversized one wastes space and adds unnecessary inertia to the drive train. The wrong disc material may degrade in the operating environment. The wrong hub style may allow shaft slippage under dynamic loading.<\/p>\n

This guide walks through the coupling selection process step by step, covering every parameter that matters for a reliable, long-service installation.<\/p>\n

\"Range
Oldham couplings are available in a wide range of sizes, bore configurations, and centre disc materials to match different application demands.<\/figcaption><\/figure>\n

Step 1: Determine the Required Torque Rating<\/h2>\n

The first and most fundamental parameter is torque. You need to establish two torque values for your application:<\/p>\n

Continuous (nominal) torque<\/strong> is the steady-state torque the coupling must transmit during normal operation. For a motor-driven system, this is typically the motor’s rated torque at the operating speed point, multiplied by any gearbox ratio between the motor and the coupling.<\/p>\n

Peak (dynamic) torque<\/strong> is the maximum torque the coupling will experience during start-up, emergency stops, load changes, or machine jams. For servo systems, this is often the motor’s peak torque \u2014 which can be 2 to 5 times the continuous rated torque \u2014 applied during rapid acceleration or deceleration cycles.<\/p>\n

The coupling’s rated torque must exceed the peak dynamic torque, not just the continuous torque. A coupling running at its rated continuous torque has a safety margin; a coupling experiencing repeated peaks at its continuous torque rating will fail from fatigue much sooner than expected.<\/p>\n

Recommended service factors by application type:<\/strong><\/p>\n

\n\n\n\n\n\n\n\n\n\n
Application Type<\/th>\nService Factor<\/th>\n<\/tr>\n<\/thead>\n
Encoder \/ resolver feedback<\/td>\n1.5<\/td>\n<\/tr>\n
Servo motor, smooth load<\/td>\n2.0<\/td>\n<\/tr>\n
Stepper motor, moderate reversals<\/td>\n2.0\u20132.5<\/td>\n<\/tr>\n
High-cycle servo with frequent reversal<\/td>\n2.5\u20133.0<\/td>\n<\/tr>\n
Industrial machinery with shock loads<\/td>\n3.0\u20134.0<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

The design torque for coupling selection is: Design Torque = Nominal Torque \u00d7 Service Factor<\/em>. Select a coupling whose rated torque equals or exceeds this design torque value.<\/p>\n

Step 2: Match the Bore Sizes to Your Shafts<\/h2>\n

Oldham couplings are manufactured with specific bore sizes, and the two hubs may have different bores to accommodate a driving shaft diameter that differs from the driven shaft diameter \u2014 for example, a 10 mm motor shaft connecting to a 14 mm ballscrew shaft.<\/p>\n

Verify that the required bore sizes are available in the coupling size you have selected for torque capacity. In some cases, the required bore sizes are only available in a coupling that is larger than the minimum torque requirement suggests \u2014 in this situation, the bore size governs the selection, and the torque rating of the larger coupling provides additional margin.<\/p>\n

For clamp-style hubs, the bore fit is a standard h7 shaft tolerance. For set-screw hubs, the shaft should be within the hub bore’s recommended tolerance range and must have a flat ground for the set screw to bear against \u2014 never tighten a set screw directly against a round shaft surface, as this deforms the shaft and creates an eccentric grip.<\/p>\n

\"Set-screw
Set-screw hub style: suitable for lighter loads and infrequent repositioning. Always ensure the shaft has a machined flat for the set screw contact face.<\/figcaption><\/figure>\n

Step 3: Quantify the Shaft Misalignment<\/h2>\n

Measure or estimate the lateral (parallel) offset between the two shaft centrelines. This must be done under operating conditions \u2014 not just at room temperature during initial assembly \u2014 because thermal expansion of the machine frame, motor, and bearings can cause the offset to change significantly once the system reaches operating temperature.<\/p>\n

As a general rule, size the coupling so that the operating misalignment is no more than 50 to 70 percent of the coupling’s maximum rated lateral offset<\/strong>. Running at the maximum rated offset continuously is technically within specification, but it places maximum stress on the disc and maximises wear rate. Operating at 50 percent of the rated offset leaves margin for measurement uncertainty, thermal drift, and bearing wear over the machine’s service life.<\/p>\n

Also assess angular misalignment. If the two shafts are not parallel \u2014 if they converge or diverge along their lengths \u2014 this angular offset must be within the coupling’s angular tolerance (typically less than 1 degree). If angular misalignment exceeds this limit, correct it mechanically before installing the coupling; do not rely on the coupling to accommodate it.<\/p>\n

Step 4: Verify the Speed Rating<\/h2>\n

The maximum operating speed of the coupling depends on both the coupling size and the operating misalignment. Larger couplings have lower speed ratings because the disc’s orbital radius \u2014 which determines the sliding velocity at the hub-disc interface \u2014 scales with the coupling’s physical dimensions. At greater misalignment, the sliding velocity is higher for the same rotational speed.<\/p>\n

Always refer to the manufacturer’s combined speed-and-misalignment chart for the specific coupling size you are considering. If the chart shows that your operating speed and misalignment combination falls outside the permissible zone, you have two options: reduce the misalignment through better shaft alignment, or select a smaller coupling (which has a higher speed rating for a given physical offset) and verify it still meets the torque requirement.<\/p>\n

Step 5: Select the Centre Disc Material<\/h2>\n

For most precision motion applications, acetal (POM)<\/strong> is the correct default choice. It provides zero backlash, runs dry without lubrication, offers good wear resistance at moderate loads, and provides electrical isolation between the two shafts.<\/p>\n

Consider alternative disc materials in the following situations:<\/p>\n