Hi Colin.
This is a problem which can occur if BOTH ends of BOTH drive shaftes are not properly supported and aligned.
The best way to do this is to make two 'U' shaped brackets which will fix up to the underside of the baseboard and solder or braze a brass collar into each of them that the shafts can turn in. The brackets need to be made from quite rigid steel which will not, itself, flex under the torque from the motor and the collars need to be quite a close fit on the shafts.
This is a problem which can occur if BOTH ends of BOTH drive shaftes are not properly supported and aligned.
The best way to do this is to make two 'U' shaped brackets which will fix up to the underside of the baseboard and solder or braze a brass collar into each of them that the shafts can turn in. The brackets need to be made from quite rigid steel which will not, itself, flex under the torque from the motor and the collars need to be quite a close fit on the shafts.