Hammering of the sinter bearings into final assembly needs to be carried out using high precision arbors.

These armors prevents bearings from getting damaged, and acts like a second calibration of the bearings while assembling.

If bearings will be applied from both sides to the main body, then these two bearings are required to be concentric. In order to sustain this concentricity, first a shaft must be inserted into both of these bearings and then they should be hammered into final assembly together, as shown in below picture.