This post is intended as information if anyone has to rebuild a spindle for a Bridgeport Interact 412:
The spindle cartridge assembly appears to be similar to other designs, but it is not. What appears to be spanner nuts that preload/secure the bearing stacks to the spindle are actually shrink fit and glued collars. Both collars have what appears to be a set screw hole and a spanner hole, but there are not any threads between the collar and spindle. My press did not have the tonnage (20 tons) to remove these collars, so I ended up cutting (actually milling) them off and will have to make new ones for re-assembly. The lesson that I have learned after breaking a couple of spanner wrenches is: In the future, look up the bearing for the ID and measure the OD of the spindle shoulder closest to the bearing. If there is not at least 5/32" (4mm), then the assembly can't be held together with threads. I hope this is helpful to someone else in the future.
The spindle cartridge assembly appears to be similar to other designs, but it is not. What appears to be spanner nuts that preload/secure the bearing stacks to the spindle are actually shrink fit and glued collars. Both collars have what appears to be a set screw hole and a spanner hole, but there are not any threads between the collar and spindle. My press did not have the tonnage (20 tons) to remove these collars, so I ended up cutting (actually milling) them off and will have to make new ones for re-assembly. The lesson that I have learned after breaking a couple of spanner wrenches is: In the future, look up the bearing for the ID and measure the OD of the spindle shoulder closest to the bearing. If there is not at least 5/32" (4mm), then the assembly can't be held together with threads. I hope this is helpful to someone else in the future.
