English
Le français
Türkçe
First establish why the key will not seat: is it too wide, too high, or does the pulley bore not fit the shaft at all? Filing the key down, hammering it into the keyway or heating the pulley and forcing it on damages both the shaft and the hub; the right solution is a key of the correct size or a pulley with a suitable keyway cut.
Three possible situations
Different shaft diameter
If the pulley comes from the old motor's shaft and the new shaft is larger, the pulley will not go onto the shaft; the key problem is only the visible side of this. In that case the pulley bore is enlarged and the keyway recut, or the pulley is replaced.
Same diameter, different keyway width
The old pulley may have been machined with an inch-size or non-standard keyway. If the pulley keyway is narrower, it can be widened; if it is wider, the key runs loose in the keyway and knocks. In that case a stepped key (one side matching the shaft, the other the pulley) or a new pulley can be considered.
Key too high
If the pulley bore goes onto the shaft but the hub will not slide fully home because of the key, the pulley keyway is too shallow. The keyway can be deepened to the standard depth.
What is needed for measurement
- Shaft diameter, key width and key height (with the key removed from the motor)
- Pulley bore diameter, keyway width and the dimension from the top of the bore to the bottom of the keyway
- Hub length and the position of the set screw on the pulley
You can verify shaft and key dimensions against the motor technical drawing.
Does the motor need to be returned?
If the motor dimension is standard, the problem lies with the pulley and the adaptation is done on the pulley side. Machining the motor shaft counts as a modification and voids the warranty. If the wrong size was chosen for a motor that has not yet been installed or run, the return and exchange conditions are explained in the return and exchange policy. To get the right shaft size from the start, use the shaft D×E values in the shop list.