Product appearance varies with coupling size and finished bore. Use the model table below for dimensions and send both shaft details for machining.
NM128 Flexible Coupling
NM128 provides 140 N.m nominal torque, up to 55 mm bore capacity and a rated speed limit of 3000 rpm. It is suited to mid-range pumps, blowers, mixers and machinery when torque, shaft fit, alignment and installation space are all within the model limits.
NM128 technical data
NM128 doubles the nominal torque of NM112 to 140 N.m and increases maximum bore to 55 mm. It is a practical candidate for machinery where shaft diameter and starting load have moved beyond the lighter NM sizes.
| Model | Nominal torque | Speed limit | D | D1 | d max | L | S | Radial | Angular |
|---|---|---|---|---|---|---|---|---|---|
| NM128 | 140 N.m | 3000 putaran per menit | 128 mm | 90 mm | 55 mm | 70 mm | 3.5 +/- 1.0 mm | 0.07 mm | 2.5 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 coupling envelope is 128 mm in diameter with a 70 mm length. Measure the actual space between surrounding structures rather than relying on a previous model number, because a larger hub can solve a bore issue while creating a guard-clearance problem.
Where this size fits
For mixers, conveyors, pumps and similar industrial drives, use the 140 N.m nominal rating as the first screen and describe how the machine starts. A loaded conveyor start and a steady pump at the same running power do not impose the same transient conditions.
Alignment and assembly
The stated separation for NM128 is 3.5 +/- 1.0 mm. Keep radial misalignment within 0.07 mm and angular misalignment within 2.5 degrees, then inspect the elastomer after commissioning if the installation previously showed uneven wear.
Prepare the NM128 RFQ
A useful NM128 quotation request combines mechanical interface and duty data: both bores, both keyways, rpm, torque or motor power, driven machine, quantity and any controlled fit. Attach the shaft drawing when shoulders or unusual keys affect machining.
Material and service conditions
NBR is standard for the flexible ring. If the drive is near heat, lubricants or process chemicals, identify the exposure and any required material so the elastomer is not chosen by appearance alone.
Compare the nearest NM sizes
When 55 mm bore capacity or 140 N.m torque is insufficient, review NM148. When the application is comfortably below those limits, NM112 may provide a smaller diameter and shorter assembly.
