taper-bush
Installation & Maintenance
Tightening torque matters because it controls how the fasteners draw the tapered surfaces together. Too little clamp can leave movement in the connection; too much can overload threads, screws or the surrounding hub. The correct number is therefore a product-and-fastener specification, not a universal “taper bushing torque.”
Fastener size and bushing geometry vary by series, so one generic torque value should not be applied across the range. Where an exact torque value is required, confirm it for the ordered model and fastener before installation. This guide shows how to use the fastener reference safely and what to verify before applying a torque wrench.
Why the specified tightening torque is model-specific
Screw diameter is only one input. Thread form, screw grade, lubrication condition, coating, number of fasteners and the bushing/hub geometry all affect the relationship between wrench torque and clamp force. A value borrowed from another brand or series can therefore produce the wrong clamp even when the nominal screw size matches.
Taper Lock fastener reference: EP-1008 to EP-5050
| EP model | A (in) | B (in) | Listed fastener |
|---|---|---|---|
| EP-1008 | 1.386 | 7/8 | 1/4 x 1/2 set screws |
| EP-1108 | 1.511 | 7/8 | 1/4 x 1/2 set screws |
| EP-1210 | 1 7/8 | 1 | 3/8 x 5/8 set screws |
| EP-1215 | 1 7/8 | 1 1/2 | 3/8 x 5/8 set screws |
| EP-1310 | 2 | 1 | 3/8 x 5/8 set screws |
| EP-1610 | 2 1/4 | 1 | 3/8 x 5/8 set screws |
| EP-1615 | 2 1/4 | 1 1/2 | 3/8 x 5/8 set screws |
| EP-2012 | 2 3/4 | 1 1/4 | 7/16 x 7/8 set screws |
| EP-2017 | 2 3/4 | 1 3/4 | 7/16 x 7/8 set screws |
| EP-2517 | 3 3/8 | 1 3/4 | 1/2 x 1 set screws |
| EP-2525 | 3 3/8 | 2 1/2 | 1/2 x 1 set screws |
| EP-3020 | 4 1/4 | 2 | 5/8 x 1 1/4 set screws |
| EP-3030 | 4 1/4 | 3 | 5/8 x 1 1/4 set screws |
| EP-3535 | 5 | 3 1/2 | 1/2 x 1 1/2 socket head cap screws |
| EP-4040 | 5 3/4 | 4 | 5/8 x 1 3/4 socket head cap screws |
| EP-4545 | 6 3/8 | 4 1/2 | 3/4 x 2 socket head cap screws |
| EP-5050 | 7 | 5 | 7/8 x 2 1/4 socket head cap screws |
How to apply torque correctly
- Use a calibrated torque wrench with the correct socket or hex engagement.
- Bring multiple fasteners up in stages instead of fully tightening one while the others are loose.
- Keep threads clean and follow the stated condition for lubrication or coating; do not improvise.
- Stop if the screw head, thread or hub shows damage, or if the bushing seats unevenly.
- Record the final maintenance value when the machine procedure requires traceability.
QD and Split Taper bushings need their own values
QD and Split Taper assemblies use different flange, barrel and fastener arrangements from the Taper Lock family. Their tightening instructions should be treated separately. A QD SF or J reference, for example, cannot inherit a Taper Lock value simply because both products connect a hub to a shaft.
The same rule applies inside each family: confirm the exact letter or model, screw specification, bore/keyway and mating component. If a service sheet is missing, request the correct technical document before putting the drive back into operation.
Metric and imperial units
When a maintenance document gives N·m and a torque wrench is marked in ft·lbf, use a controlled engineering conversion rather than rounding by feel. Keep the original source value and unit in the work order, then record the converted tool setting separately. Unit conversion does not resolve an uncertain model or unknown screw grade.
Frequently asked questions
Why is there no single torque number for every taper lock bushing?
Fastener size, quantity, thread condition and bushing geometry change across models. Use the specified value for the exact assembly.
Can fastener size be used to calculate the torque myself?
Fastener size helps identify the assembly but is not sufficient by itself. Use approved installation data for the exact bushing and screw set.
Related products and resources
Need help with a real application?
Send the model, shaft diameter, keyway or drawing so the enquiry can be checked against the correct bushing family.