Product appearance varies with coupling size and finished bore. Use the model table below for dimensions and send both shaft details for machining.
NM168 Flexible Coupling
NM168 provides 500 N.m nominal torque, up to 75 mm bore capacity and a rated speed limit of 3000 rpm. It is suited to higher-torque pumps, compressors and process equipment when torque, shaft fit, alignment and installation space are all within the model limits.
NM168 technical data
NM168 is the highest-torque size in this range that still carries a 3000 rpm rated speed limit. With 500 N.m nominal torque and a 75 mm maximum bore, it can cover substantial machinery interfaces without the speed reduction that begins at NM194.
| Model | Nominal torque | Speed limit | D | D1 | d max | L | S | Radial | Angular |
|---|---|---|---|---|---|---|---|---|---|
| NM168 | 500 N.m | 3000 rpm | 168 mm | 124 mm | 75 mm | 90 mm | 3.5 +/- 1.5 mm | 0.10 mm | 2.0 deg |
D, D1, d max, L, S and radial values are in millimetres. Angular displacement is shown in degrees. On smaller screens, drag the table horizontally to view all columns.
Fit and machining checks
The outside diameter is 168 mm and the axial length is 90 mm. Verify both the rotating clearance and service access around the coupling; a high-capacity model is not useful if the guard or adjacent equipment prevents correct assembly and inspection.
Where this size fits
For larger pumps, process drives and general machinery, screen NM168 against the 500 N.m nominal rating, then add the true starting and shock behavior. Its 3000 rpm limit is an important differentiator when comparing it with the next larger sizes.
Alignment and assembly
NM168 uses S 3.5 +/- 1.5 mm, with 0.10 mm radial and 2.0 degree angular limits. Alignment should be checked in the machine’s final operating position, especially when heavy connected equipment can settle or move the base.
Prepare the NM168 RFQ
State both shaft bores and keyways, rpm, torque or motor power, driven machine, quantity and destination. If the bore approaches 75 mm, include the exact keyway and fit to support a proper hub-machining review.
Material and service conditions
NBR is standard. If the flexible element will see elevated temperature, oil contamination or another aggressive environment, describe it so the elastomer requirement can be confirmed with the NM168 offer.
Compare the nearest NM sizes
NM194 provides more torque and bore capacity, but its rated speed limit drops to 1500 rpm. Do not move up from NM168 until both the speed change and the larger envelope have been checked.
